A student is holding a test tube containing 5.0 milliliters of water. A sample of NH4Cl(s) is placed
in the test tube and stirred. Describe the heat flow between the test tube and the student's hand.

Answers

Answer 1

Answer:

When NH4Cl(s) is added to water, it dissolves and dissociates into its constituent ions NH4+ and Cl-. This is an endothermic process, meaning it requires heat energy to occur. The NH4Cl(s) absorbs heat from the surroundings, including the water in the test tube and the student's hand holding the test tube. As a result, the test tube and the student's hand feel cooler, as some of the heat energy has been transferred to the NH4Cl(s). Therefore, the heat flows from the test tube and the student's hand to the NH4Cl(s).


Related Questions

A sample of helium gas occupies 2.65 l at 1.20 atm. what pressure would
this sample of gas exert in a 1.50-l container at the same temperature?
(use boyle's law: v1p1=v2p2)

Answers

A sample of helium gas that occupies 2.65 L at 1.20 atm would exert a pressure of 3.18 atm in a 1.50-L container at the same temperature, according to Boyle's Law.

To know the pressure exerted by a sample of helium gas that occupies 2.65 L at 1.20 atm when it's compressed to 1.50 L at the same temperature, using Boyle's Law (V₁P₁ = V₂P₂).

Here's the step-by-step explanation:
1. Identify the initial volume (V₁), initial pressure (P₁), and final volume (V₂):
  V₁ = 2.65 L
  P₁ = 1.20 atm
  V₂ = 1.50 L

2. Apply Boyle's Law to find the final pressure (P2):
  V₁P₁ = V₂P₂

3. Plug in the values and solve for P₂:
  (2.65 L)(1.20 atm) = (1.50 L)P₂

4. Calculate P₂:
  P₂= (2.65 L × 1.20 atm) / 1.50 L
  P₂= 3.18 atm
A sample of helium gas that occupies 2.65 L at 1.20 atm would exert a pressure of 3.18 atm in a 1.50-L container at the same temperature, according to Boyle's Law.

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Benzene at 20°C has a viscosity of 0. 000651 Pa. S. What shear stress is required to deform this fluid at a velocity gradient of 4900 s-1 ?

Answers

Viscosity is a measure of a fluid's resistance to deformation under shear stress. In this case, Benzene has a viscosity of 0.000651 Pa. S at a temperature of 20°C. To calculate the shear stress required to deform Benzene at a velocity gradient of 4900 s-1, we can use the formula: shear stress = viscosity x velocity gradient.

Plugging in the values given, we get:

Shear stress = 0.000651 Pa. S x 4900 s-1
Shear stress = 3.191 Pa

Therefore, a shear stress of 3.191 Pa is required to deform Benzene at a velocity gradient of 4900 s-1. This means that if a force greater than 3.191 Pa is applied to Benzene, it will flow or deform under shear stress.

It is important to note that the viscosity of a fluid can change with temperature, pressure, and other factors, which can affect the fluid's ability to flow or deform under shear stress.

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If 3.1127 moles of H2O are reacted, how many moles of CO2 will be produced?

Answers

The balanced chemical equation for the reaction between H2O and CO2 is:

H2O + CO2 -> H2CO3

From the balanced equation, we can see that one mole of CO2 reacts with one mole of H2O to produce one mole of H2CO3. Therefore, the number of moles of CO2 produced will be equal to the number of moles of H2O reacted.

So, if 3.1127 moles of H2O are reacted, then 3.1127 moles of CO2 will be produced.

A stone weighing 1. 5 kilograms is resting on a rock at a height of 20 meters above the ground. The stone rolls down 10 meters and comes to rest on a patch of moss. The gravitational potential energy of the stone on the moss is joules. (Use PE = m × g × h, where g = 9. 8 N/kg. )

Answers

The gravitational potential energy of the stone on the moss is 147 joules.

Gravitational potential energy is the energy possessed by an object due to its position in a gravitational field. It is defined as the energy required to move an object of a given mass from infinity to its current position against the force of gravity.

In the case of the stone weighing 1.5 kilograms resting on a rock at a height of 20 meters above the ground, the gravitational potential energy can be calculated using the formula PE = m × g × h, where m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object above the ground.

So, in this case, the gravitational potential energy of the stone at a height of 20 meters can be calculated as:

PE = m × g × h
PE = 1.5 kg × 9.8 N/kg × 20 m
PE = 294 J

When the stone rolls down 10 meters and comes to rest on a patch of moss, its height above the ground decreases to 10 meters. The gravitational potential energy of the stone on the moss can be calculated using the same formula:

PE = m × g × h
PE = 1.5 kg × 9.8 N/kg × 10 m
PE = 147 J

Therefore, the gravitational potential energy of the stone on the moss is 147 joules.

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If the mass of aluminum is 1. 80 g and iodine is 2. 30 g how much of the excess reagent remains after the reaction



2Al + 3I2 > 2AlI3

Answers

Total, 0.77 g of I2 is the amount of the excess reagent that remains after the reaction.

To determine the excess reagent remaining, we first need to find the limiting reagent.

The balanced equation tells us that 2 moles of Al react with 3 moles of I₂ to form 2 moles of AlI₃. We can use this information to calculate the theoretical yield of AlI3 based on the amount of each reactant;

moles of Al = 1.80 g / 26.98 g/mol = 0.067 moles

moles of I₂  = 2.30 g / 253.81 g/mol = 0.009 moles

Since the stoichiometry of the reaction is 2:3 for Al and I₂ , respectively, we can see that I₂ is the limiting reagent. Thus, all of the Al will react, while some of the I₂ will be left over.

The amount of AlI₃ that can be formed from the limiting reagent (I2) is:

moles of AlI₃ = 0.009 moles I₂  × (2 moles AlI₃ / 3 moles I₂ )

= 0.006 moles AlI₃

The mass of AlI₃ that can be formed is;

mass of AlI₃ = 0.006 moles × 407.82 g/mol

= 2.47 g

Since we know that only 2.30 g of I₂  was present initially, we can calculate the amount of excess I₂ remaining after the reaction;

excess I₂  = 2.30 g - (0.009 moles I₂  × 253.81 g/mol)

= 0.77 g

Therefore, 0.77 g of reagent that remains after the reaction.

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⁻⁻⁻⁻⁻ results in a new substance and it cannot be reversed by physical means

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Chemical change results in a new substance and it cannot be reversed by physical means.

What is chemical change?

Chemical changes is said to occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances  and are not reversible except by further chemical reactions.

Examples of chemical change would be:

Burning a piece of paper would be a chemical change, and also baking a cake.

It is also worthy to note that in a physical change, no new substance is formed and also a  chemical change is always accompanied by one or more new substance.

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PLEASE HELP!!!!


A 60mL HCl solution is titrated with 25mL of a 0. 60M KOH solution. What is the concentration of the HCl solution?



1) 2. 5 mol/L


2) 0. 65 mol/L


3) 1. 56 mol/L


4) 0. 25 mol/L

Answers

The concentration of the HCl solution is 0.25 mol/L .

To determine the concentration of the HCl solution when titrated with 25mL of a 0.60M KOH solution, we need to use the following equation:
moles of HCl = moles of KOH

First, let's find the moles of KOH:
moles of KOH = volume (L) × concentration (M)
moles of KOH = 0.025 L × 0.60 mol/L
moles of KOH = 0.015 mol

Since the moles of HCl = moles of KOH, we have 0.015 mol of HCl. Now, we can calculate the concentration of the HCl solution:
concentration of HCl (M) = moles of HCl / volume of HCl (L)

The volume of HCl solution is given as 60 mL, which is equal to 0.060 L. Therefore:
concentration of HCl (M) = 0.015 mol / 0.060 L
concentration of HCl (M) = 0.25 mol/L
The concentration of the HCl solution is 0.25 mol/L (option 4).

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A solution contains 37.5 grams of calcium carbonate (caco3) in 500 ml of
water. what is the concentration of this solution?

Answers

The concentration of the solution is 0.748 M.

To find the concentration of the solution, we need to calculate the number of moles of calcium carbonate present in the solution.

First, we need to determine the molecular weight of calcium carbonate ([tex]CaCO3[/tex]).

[tex]CaCO3[/tex] = 1 x Ca + 1 x C + 3 x O

= 40.08 g/mol + 12.01 g/mol + (3 x 16.00 g/mol)

= 100.09 g/mol

Next, we can use the formula:

concentration (in mol/L) = moles of solute / volume of solution (in L)

We have 37.5 grams of calcium carbonate in 500 ml of water. To convert ml to L, we divide by 1000:

volume of solution = 500 ml / 1000 ml/L = 0.5 L

moles of calcium carbonate = mass / molecular weight

= 37.5 g / 100.09 g/mol

= 0.374 moles

Therefore, the concentration of the solution is:

concentration = 0.374 moles / 0.5 L

= 0.748 M

The concentration of the solution is 0.748 M.

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How many molecules are in 9. 44 moles of AlCl3? *




Pleaseeeee helpppp

Answers

There are approximately 3.40 x 10²⁴ molecules in 9.44 moles of AlCl₃.

This is calculated by using Avogadro's number (6.022 x 10²³) and multiplying it by the number of moles given.


To calculate the number of molecules in a given amount of substance, we use Avogadro's number, which is 6.022 x 10²³. This number represents the number of particles (molecules, atoms, ions) in one mole of a substance.

In this case, we are given the number of moles of AlCl₃, which is 9.44. To calculate the number of molecules, we simply multiply the number of moles by Avogadro's number:

9.44 moles AlCl₃ x 6.022 x 10²³ molecules/mole = 3.40 x 10²⁴ molecules AlCl₃

Therefore, there are approximately 3.40 x 10²⁴ molecules in 9.44 moles of AlCl₃.

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A cylinder of Krypton has contains 17 L of Ar at 22. 8 atm and 112 degrees celsisus. How many moles are in the


cylinder?

Answers

A cylinder of Krypton has contains 17 L of Ar at 22. 8 atm and 112 degrees celsisus. There are 0.824 moles of Ar in the cylinder.

The number of moles of Ar in the cylinder can be calculated using the ideal gas law equation: PV = nRT, where P is the pressure in atm, V is the volume in liters, n is the number of moles, R is the universal gas constant, and T is the temperature in Kelvin.

To use this equation, the given temperature of 112 degrees Celsius must be converted to Kelvin by adding 273.15 to get 385.15 K. The pressure of 22.8 atm and volume of 17 L are already in the correct units.

R can be found using the equation R = 0.0821 L atm/(mol K), and plugging in the values for P, V, n, R, and T gives: (22.8 atm)(17 L) = n(0.0821 L atm/(mol K))(385.15 K) n = 0.824 mol

The number of moles of Ar in the cylinder can be found using the ideal gas law equation, which requires the pressure, volume, temperature, and the gas constant. After converting the given temperature to Kelvin, the calculation yields 0.824 moles of Ar.

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Name the following compounds:
a. C2H4 or H2C=CH2
b. CsH6 or CH3CH=CH2
C. C4H8 or H2C=CHCH2CH3
d. CaHs or CH3CH2=CH2CH3
e. CsH1o or CHaCH2CH2CH=CH2

Answers

a. C2H4 or H2C=CH2 is called ethene or ethylene
b. CsH6 or CH3CH=CH2 is called cyclohexene
c. C4H8 or H2C=CHCH2CH3 is called 1-butene
d. CaHs or CH3CH2=CH2CH3 is called 1-pentene
e. CsH1o or CHaCH2CH2CH=CH2 is called 1-decene

Chemistry Calculating moles.

Answers

The molarity of an aqueous solution containing 6.7 moles of potassium chloride in 0.63L is 10.6 M.

The quantity of solute molecules per litre of solution is known as a solution's molarity. In this issue, we are given the number of moles of solute (potassium chloride) and the volume of the solution. We can use this information to calculate the molarity of the solution using the following formula:

Volume of solution (V) / moles of solute (n) equals molarity (M).

Substituting the given values, we get:

Molarity (M) = 6.7 moles / 0.63 L = 10.6 M

Therefore, the molarity of the solution is 10.6 M, rounded to the tenths place.

It is important to note that molarity is a measure of concentration and is affected by both the amount of solute and the volume of the solution. Thus, it is important to accurately measure the volume of the solution to calculate the molarity correctly.

Furthermore, it is important to use caution when handling concentrated solutions such as this one, as they can be hazardous. Proper safety equipment and procedures should be followed when working with such solutions.

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1) what type of solution (saturated or unsaturated ) is present for Pb(NO3)2 if at approximately 25 degrees c


,65 grams of the substance are present in the 100 grams of H2O



2)40 grams of KCl are dissolve in 100 grams of H2O at 10 degrees c how many grams will not dissolve



3)how many grams of H2O are needed to dissolve 50 grams of KClO3 at 70 degrees C



4)how many grams of K2Cr2O7 will dissolve in 75 grams of H2O at 90 degrees C



5) 59 grams of CaCl2 are dissolve in 100 grams of water at approximately 25 degrees c how many more grams of CaCl2 must be added to saturate the solution

Answers

1) The solution is saturated. 2) 40 grams of KCl has dissolved in 100 grams.  3) 50 grams of KClO₃ will dissolve. 4) 75 grams of H₂O can dissolve 24.6 grams. 5) To saturate 28.4 grams of CaCl₂ must be added.

What is saturated?

Saturated is a term used to describe a state of being filled to capacity, or containing the maximum amount possible. It is most commonly used in reference to liquids, where it indicates that no more of a given substance can be dissolved into the liquid. In chemistry, saturation refers to the point at which a solution has reached its maximum solubility.

1) The solution is saturated because 65 grams of Pb(NO₃)₂ has dissolved in 100 grams of H₂O at 25°C.

2) 40 grams of KCl has dissolved in 100 grams of H₂O at 10°C, so no more will dissolve.

3) 50 grams of KClO₃ will dissolve in 92.5 grams of H₂O at 70°C.

4) 75 grams of H₂O can dissolve 24.6 grams of K₂Cr₂O7 at 90°C.

5) At 25°C, 59 grams of CaCl₂ has dissolved in 100 grams of H₂O. To saturate the solution, an additional 28.4 grams of CaCl₂ must be added.

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A 1500. 0 gram piece of wood with a specific heat capacity of 1. 8 g/JxC absorbs 67,500 Joules of heat. If the final temperature of the wood is 57C, what is the initial temperature of the wood? (2 sig figs)

Answers

If the final temperature of the wood is 57C, then the initial temperature of the wood would have been 32.00 ºC.

To solve the problem, we can use the formula,

Q = m * c * ΔT , amount of heat absorbed by the wood is Q, its mass is m, specific heat capacity is c, the change in temperature is ΔT.

We know that m = 1500.0 g, c = 1.8 J/gºC, Q = 67,500 J, and the final temperature T₂ = 57ºC. We need to find the initial temperature T₁.

First, we can calculate the change in temperature,

ΔT = T₂ - T₁

ΔT = 57ºC - T₁

Next, we can rearrange the formula to solve for T₁,

T₁ = T₂ - (Q / (m * c))

T₁ = 57ºC - (67,500 J / (1500.0 g * 1.8 J/gºC))

T₁ = 57ºC - 25ºC

T₁ = 32ºC

Therefore, the initial temperature of the wood was 32.00 ºC.

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What is the temperature of 5. 16g of helium gas at a pressure of 785 mmHg that occupies a 1. 00 L container?

Answers

The temperature of 5.16g of helium gas at a pressure of 785 mmHg that occupies a 1.00 L container is approximately 248 Kelvin.

The temperature of 5.16g of helium gas at a pressure of 785 mmHg that occupies a 1.00 L container can be calculated using the ideal gas law equation:

PV = nRT

where P is the pressure in atm, V is the volume in L, n is the number of moles, R is the gas constant (0.0821 L atm/mol K), and T is the temperature in Kelvin.

Convert the pressure from mmHg to atm by dividing by 760 mmHg/atm:

785 mmHg ÷ 760 mmHg/atm = 1.033 atm

Calculate the number of moles of helium gas using its molecular weight:

molecular weight of helium = 4.00 g/mol

moles of helium = 5.16 g ÷ 4.00 g/mol = 1.29 mol

Now, we can rearrange the ideal gas law equation to solve for T:

T = PV ÷ nR

T = (1.033 atm)(1.00 L) ÷ (1.29 mol)(0.0821 L atm/mol K)

T = 248 K

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When 50 ml of water are added to 50 ml of water, the total volume of water is 100 ml. but if 50 ml of water are added to 50 ml of ethanol, the total volume will be less than 100 ml. why is this

Answers

This is because when water is added to ethanol, the two substances form a homogenous solution, meaning the two substances mix together to form a single molecular solution.

As a result, the water molecules and ethanol molecules take up the same amount of space, meaning the total volume of the mixture is less than the sum of the original two volumes (50 ml of water + 50 ml of ethanol = less than 100 ml).

This phenomenon is known as "volume contraction" and is caused by the intermolecular forces between water and ethanol molecules. This contraction also occurs when two other liquids are mixed together in certain combinations.

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A quantity of gas has a volume of 15 liters at 52. 0°C and 89. 9 kPa of pressure. To what volume must the gas be decreased


for the gas to be under standard temperature and pressure conditions?





4. 4L


8. 7L


0. 39 L


11L


Od

Answers

The gas must be decreased to a volume of 4.4 L to be under STP. The answer is option (a).

Using the ideal gas law, PV=nRT, we can solve for the number of moles of gas:

n = PV/RT

where P is pressure, V is volume, R is the gas constant (0.0821 L·atm/mol·K), and T is temperature in Kelvin.

First, we need to convert the temperature to Kelvin:

52.0°C + 273.15 = 325.15 K

Then we can calculate the number of moles of gas:

n = (89.9 kPa)(15 L)/(0.0821 L·atm/mol·K)(325.15 K) = 0.703 mol

To find the volume at standard temperature and pressure (STP), we can use the fact that at STP, the pressure is 1 atm and the temperature is 273.15 K. So we can set up a ratio:

(P1)(V1)/(n1)(T1) = (P2)(V2)/(n2)(T2)

where P1 = 89.9 kPa, V1 = 15 L, n1 = 0.703 mol, T1 = 325.15 K, P2 = 1 atm, T2 = 273.15 K, and we want to solve for V2:

(89.9 kPa)(15 L)/(0.703 mol)(325.15 K) = (1 atm)(V2)/(0.703 mol)(273.15 K)

V2 = (1 atm)(15 L)(0.703 mol)(273.15 K)/(89.9 kPa)(325.15 K) = 4.4 L

Therefore, the gas must be decreased to a volume of 4.4 L to be under STP. The answer is option (a).

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Complete question

A quantity of gas has a volume of 15 liters at 52. 0°C and 89. 9 kPa of pressure. To what volume must the gas be decreased for the gas to be under standard temperature and pressure conditions?

a. 4. 4L

b. 8. 7L

c. 0. 39 L

d. 11L

The formula for ethanol is ch3ch2oh. choose the mole
ratio of h to c in this molecule.

Answers

The mole ratio of H to C in ethanol is 1:3.

The mole ratio of H to C in ethanol, which has a chemical formula of CH3CH2OH, can be determined by looking at the number of atoms of each element present in the molecule. In this case, there are six carbon atoms and two hydrogen atoms. Therefore, the mole ratio of H to C in ethanol is 1:3.

This means that for every one mole of hydrogen atoms in ethanol, there are three moles of carbon atoms present. This ratio is important because it can be used to calculate the amount of reactants needed to produce a certain amount of product in a chemical reaction.

For example, if ethanol was being produced from a reaction involving a certain amount of carbon and hydrogen, the mole ratio of H to C could be used to determine how much of each reactant was needed to produce a specific amount of ethanol.

Overall, understanding the mole ratio of H to C in a molecule like ethanol can be useful in a variety of chemical applications and reactions.

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What substituent(s) might you add to convert benzoic acid into a very strong acid? Draw its structure and explain your reasoning

Answers

To convert benzoic acid into a very strong acid, you can add electron-withdrawing substituents like nitro groups (-NO₂) to the aromatic ring. These substituents increase the acidity of the carboxylic acid group by stabilizing the negative charge on the conjugate base, the benzoate ion.


Let us discuss this in detail.

1. Add a nitro group (-NO₂) as a substituent to the aromatic ring of benzoic acid. You can add more than one nitro group to further increase acidity.

2. The electron-withdrawing nature of the nitro group stabilizes the negative charge on the conjugate base (benzoate ion) by delocalizing the negative charge through resonance.

3. As a result, the equilibrium between benzoic acid and its conjugate base shifts towards the conjugate base, making the modified benzoic acid a stronger acid.

The structure of the modified benzoic acid with a nitro group at the ortho or para position is as follows:

      O
      ||
-C₆H₄-NO₂-C-O-H

Remember, adding more electron-withdrawing substituents like nitro groups will further increase the acidity of the benzoic acid derivative.

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2) A 45. 7 g sample of glass was brought to thermal equilibrium with boiling water and then


transferred to 250. 0 g of water that was at 22. 5 °C. This combination reached thermal


equilibrium at 24. 2 °C. What is the specific heat capacity of glass?

Answers

The specific heat capacity of glass is 0.84 J/g°C.

To calculate the specific heat capacity of the glass, follow these steps:
1. Determine the energy gained by the water: Q_water = m_water * c_water * ΔT_water
2. Determine the energy lost by the glass: Q_glass = m_glass * c_glass * ΔT_glass
3. Since energy is conserved, Q_water = Q_glass
4. Solve for the specific heat capacity of the glass (c_glass).


m_glass = 45.7 g
m_water = 250.0 g
c_water = 4.18 J/g°C
Initial temperature of water (T1_water) = 22.5°C
Final temperature (T2) = 24.2°C
ΔT_water = T2 - T1_water = 1.7°C
ΔT_glass = T2 - 100°C = -75.8°C

1. Q_water = 250.0 g * 4.18 J/g°C * 1.7°C = 1776.7 J
2. Q_glass = 45.7 g * c_glass * (-75.8°C)
3. 1776.7 J = 45.7 g * c_glass * (-75.8°C)
4. c_glass = 0.84 J/g°C

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The local atmospheric pressure is 392 mm of Hg. What is the pressure in kpa? Your answer should not include units; simply type in the correct number for the pressure in kilopascals. Be sure to follow significant digit rules!

Answers

To convert the local atmospheric pressure from mm of Hg to kPa, follow these steps:

1. Calculate the conversion of mm of Hg to atm:
  1 atm = 760 mm of Hg
  392 mm Hg × (1 atm / 760 mm Hg) = 0.5158 atm

2. Convert atmospheres to kilopascals (kPa):
  1 atm = 101.325 kPa
  0.5158 atm × (101.325 kPa / 1 atm) = 52.24 kPa

Following significant digit rules, the pressure in kilopascals is 52.2 kPa.

What is atmospheric pressure?

Atmospheric pressure is the force exerted by the weight of the Earth's atmosphere on a unit of area at a given point on the Earth's surface. The atmosphere is composed of gases, mainly nitrogen (78%) and oxygen (21%), and other trace gases such as argon, carbon dioxide, neon, and helium. These gases are held near the Earth's surface by the force of gravity, and they exert a pressure on the surface below.

Atmospheric pressure is usually measured in units of millibars (mb) or inches of mercury (inHg), and it varies depending on factors such as altitude, temperature, and weather conditions. At sea level, the standard atmospheric pressure is around 1013 mb or 29.92 inHg, but it decreases as you go higher in altitude, because there is less air above you to exert pressure.

Changes in atmospheric pressure can have a significant impact on weather patterns, and can cause changes in temperature, wind patterns, and precipitation. Weather forecasters often use changes in atmospheric pressure as a key indicator in predicting weather patterns.

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A sample of crushed rock is found to have 4. 81 x 10^21 atoms of gold, how many moles of hold are present in this sample?

Answers

The sample of crushed rock containing 4.81 x 10²¹ atoms of gold corresponds to 0.008 moles of gold.

The number of moles of gold in the sample of crushed rock can be calculated by dividing the total number of atoms of gold by Avogadro's number, which represents the number of particles in one mole of a substance.

First, we convert the given value of atoms of gold to moles by dividing by Avogadro's number (6.022 x 10²³ atoms per mole).

Number of moles of gold = 4.81 x 10²¹ atoms / 6.022 x 10²³ atoms/mol

Simplifying the calculation, we get:

Number of moles of gold = 0.00799 moles

Therefore, there are approximately 0.008 moles of gold present in the sample of crushed rock.

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At a festival, spherical balloons with a radius of 140cm are to be inflated with hot air and released. The air at the festival will have a temperature of 25 C and must be heated to100 C to make the balloons float. 1. 00kg of butane(C4H10) fuel are available to be burned to heat the air. Calculate the maximum number of balloons that can be inflated with hot air

Answers

The maximum number of balloons that can be inflated with hot air is 0.017 balloons.

What is inflated?

Inflation is an economic concept that refers to the increase in the cost of goods and services over time. High inflation can lead to a decrease in purchasing power, as prices rise faster than wages.

The amount of heat energy required to heat 1 kg of air from 25 C to 100 C is 150 kJ.

Since 1kg of butane (C₄H₁₀) fuel releases around 46.9 kJ of energy when burned, we can calculate how much fuel is needed to heat 1 kg of air.

150 kJ / 46.9 kJ = 3.19 kg of fuel

To calculate the maximum number of balloons that can be inflated with hot air, we need to know the volume of air contained in the balloons.

Volume of the balloon = 4/3πr3

Volume of the balloon = 4/3π(1403)

Volume of the balloon = 1.71 m3

To calculate the mass of air contained in the balloon, we can use the ideal gas law, where PV = nRT.

P = Pressure, V = Volume, n = number of moles, R = gas constant, T = Temperature

Pressure = 1 atm

Volume = 1.71 m3

Number of moles = 1

Gas constant = 8.314

Temperature = 25 C

nRT/V = P

1 (8.314) (298.15) / 1.71

= 183.6 kg

Therefore, the mass of air contained in the balloon is 183.6 kg.

To determine the maximum number of balloons that can be inflated with hot air, we need to know the total mass of fuel available.

1 kg of fuel x 3.19 = 3.19 kg of fuel

To calculate the maximum number of balloons that can be inflated with hot air, we need to divide the mass of fuel available by the mass of air contained in the balloon.

3.19 kg / 183.6 kg = 0.017

Therefore, the maximum number of balloons that can be inflated with hot air is 0.017 balloons.

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150.0g of steam at 145°C would need to lose how many joules of energy to become a liquid at 98°C? How
many cal of energy would that be?

Answers

The amount of heat that would be given out is 14.1kJ.

What is the heat capacity?

Heat capacity is a physical property that describes the amount of heat required to raise the temperature of a substance by one degree Celsius. We know that the heat capacity of steam is 2J/g/°C.

We can tell that;

H = mcdT

H = heat that is absorbed or evolved

m = mass of the object

c = Heat capacity of the object

dT = temperature change

Then we have that;

H = 150 * 2 * (98 - 145)

H = -14.1kJ This is the heart lost

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Calculate the average rate of reaction for the time interval from 180s to 300s

Answers

The average rate of reaction for the time interval from 180s to 300s is 0.00083 M/s.

To calculate the average rate of reaction for a given time interval, we need to know the change in the concentration of a reactant or product over that time period. Let's assume that we have that information.

The average rate of reaction from 180s to 300s can be calculated using the following formula:

average rate = (change in concentration)/(change in time)

Let's say that the concentration of a product increased from 0.05 M to 0.15 M over the time interval from 180s to 300s. The change in concentration is:

change in concentration = final concentration - initial concentration

change in concentration = 0.15 M - 0.05 M

change in concentration = 0.10 M

The change in time is:

change in time = final time - initial time

change in time = 300 s - 180 s

change in time = 120 s

Now we can substitute these values into the formula to find the average rate of reaction:

average rate = (change in concentration)/(change in time)

average rate = (0.10 M)/(120 s)

average rate = 0.00083 M/s

Therefore, the average rate of reaction for the time interval from 180s to 300s is 0.00083 M/s.

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What relationship is described by the arrhenius equation, k = ae -(ea / rt)?

Answers

The Arrhenius equation describes the relationship between the rate constant (k) of a chemical reaction and the temperature (T) at which the reaction occurs. The equation is given as:

k = Ae^(-Ea/RT)

where A is the pre-exponential factor or frequency factor, Ea is the activation energy required for the reaction to occur, R is the gas constant, and e is the base of the natural logarithm.

The Arrhenius equation indicates that as the temperature of a chemical reaction increases, the rate constant also increases exponentially.

The activation energy term (Ea) represents the minimum energy required for reactants to form products, and the pre-exponential factor (A) represents the frequency of successful collisions between reactant molecules.

This equation is commonly used in the study of chemical kinetics, which is the study of the rates of chemical reactions and the factors that affect them.

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Which pair of elements has the most similar Lewis structures?


N and S


N and P


F and Ne


F and Ar

Answers

The pair of elements that have the most similar Lewis structures are F and Ne.

The Lewis structure of an atom shows its valence electrons as dots around the symbol representing the nucleus. Atoms with similar Lewis structures have similar numbers of valence electrons and, therefore, similar chemical properties.

N and S have different numbers of valence electrons (5 and 6, respectively), so their Lewis structures are different.

P and F have different numbers of valence electrons (5 and 7, respectively), and the placement of the dots on their Lewis structures is different.

F and Ne both have 7 valence electrons and would have similar Lewis structures, with one dot representing each valence electron. They are both nonmetals and are found in the same period of the periodic table, which also contributes to their similar chemical properties.

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When sodium hydroxide reacts with a cropper nitrate solution, the reaction vessel needs to be kept on ice to slow down the reaction what does describes this reaction

Answers

When sodium hydroxide reacts with a copper nitrate solution, the reaction vessel needs to be kept on ice to slow down the reaction. This describes an exothermic reaction.

An exothermic reaction is a type of reaction which releases heat.

The cooling provided by the ice helps control the reaction rate and prevents it from becoming too vigorous or unmanageable.

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How does a scientist make two solutions with the same molarity?
OA. By dissolving the maximum amount of each substance in the
same volume of water
OB. By dissolving the same number of moles of each substance in the
same volume of water
OC. By dissolving 1 mole of each substance in enough water to make
sure dissolving is complete
OD. By dissolving the same number of grams of each substance in the
same volume of water
SUBMIT

Answers

The term molarity is an important method which is used to calculate the concentration of a solution. By dissolving the same number of moles of each substance in the same volume of water we can make solutions of same molarity. The correct option is B.

Molarity is defined as the number of moles of the solute present per litre of the solution. It is represented as 'M' and its unit is mol / L. The term molarity is also called the molar concentration.

When same number of moles of substances are dissolved in the same volume of water, then the two solutions have same molarity.

Thus the correct option is B.

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Dead plant material can be compressed into coal (organic). the rock gets buried within the earth. the heat and pressure from the overlying material turn this coal into anthracite coal. what types of rocks are being described in this process? *


a: sedimentary and metamorphic

b: sedimentary and igneous

c: metamorphic and igneous

d: igneous, metamorphic and sedimentary

Answers

The types of rocks being described in this process are sedimentary and metamorphic. (A)

Dead plant material, which is organic, is compressed into coal, which is a type of sedimentary rock. The coal is then buried within the earth and subjected to heat and pressure from the overlying material, which turns it into anthracite coal, a type of metamorphic rock.

Sedimentary rocks are formed from the accumulation and cementation of sediment, such as dead plant material. Metamorphic rocks are formed from the transformation of existing rocks under intense heat and pressure. In this case, the coal is transformed into anthracite coal through the process of metamorphism.

Igneous rocks are not mentioned in this process, as they are formed from the cooling and solidification of magma or lava, and do not play a role in the formation of coal. Therefore, the correct answer is A: sedimentary and metamorphic.

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