Mrs. B sets up two beakers that contain the same amount of water. She has two blocks of different materials that she labels "A" and "B." She places one block in each beaker. Block A sinks and Block B floats. Why?​

AnswerTherefore, you left approximately 1.202 x 10^23 molecules of CaCO3 on the concrete after drawing with a 25g chalk piece outside for 5 minutes.

Explanation:

To solve this problem, we need to use the concept of conservation of mass, which states that matter cannot be created or destroyed, only transformed from one form to another. Therefore, the total mass of the chalk before and after drawing must be equal.

The mass of the chalk before drawing is 25 g. After drawing for 5 minutes, the mass of the chalk is 5 g. Therefore, the mass of chalk that was used for drawing is:

25 g - 5 g = 20 g

Next, we need to convert the mass of the chalk used to the number of molecules. The molar mass of CaCO3 is 100.09 g/mol, which means that one mole of CaCO3 contains 6.022 x 10^23 molecules.

To calculate the number of molecules of chalk used for drawing, we can use the following steps:

Calculate the number of moles of CaCO3 used:

20 g / 100.09 g/mol = 0.1998 mol

Calculate the number of molecules of CaCO3 used:

0.1998 mol x 6.022 x 10^23 molecules/mol = 1.202 x 10^23 molecules

Answer:Sodium

Explanation:Sodium has 11 protons, 11 nuetrons, and 12 electrons

The molarity of the sodium hydroxide solution is 0.0911 M.

We must figure out how many molecules of potassium hydrogen phthalate there are.

moles of KHP = mass / molar mass = 0.600 g / 204.22 g/mol = 0.00294 mol

We know that 0.00294 moles of NaOH were used in the titration because one mole of KHP interacts with one mole of NaOH. This data can be used to determine the molarity of the NaOH solution:

molarity of NaOH = moles of NaOH / volume of NaOH used in liters

volume of NaOH = 32.21 mL = 0.03221 L

calculation of  the molarity of NaOH:

molarity of NaOH = 0.00294 mol / 0.03221 L = 0.0911 M

The molarity of the sodium hydroxide solution is 0.0911 M.

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Answer:

22.24°C.

Explanation:

The change in temperature of the iron can be calculated using the formula: ΔT = Q / (m * c), where ΔT is the change in temperature, Q is the heat added, m is the mass of the substance and c is the specific heat capacity.

Substituting the given values into the formula: ΔT = 115 cal / (47.0 g * 0.11 cal/g⋅°C) ≈ 22.24°C

So, the change in temperature of the iron is 22.24°C.

the normality of the solution that results when 4.0g of Al(NO₃)₃ (MW = 213.0) is dissolved in enough water to give 250mL of solution the molarity of the solution is 0.0751 M.

To calculate the normality and molarity of the solution, we need to know the number of moles of Al(NO₃)₃ in the solution.

The number of moles can be calculated as:

moles = mass / molar mass

where mass is the mass of Al(NO₃)₃ and molar mass is the molecular weight of Al(NO₃)₃

Substituting the given values, we get:

moles = 4.0 g / 213.0 g/mol = 0.01878 mol

The volume of the solution is given as 250 mL, which is equivalent to 0.25 L.

The normality of the solution is defined as the number of equivalents of solute per liter of solution. For Al(NO₃)₃, each mole of the compound produces 3 moles of ions, so the number of equivalents of Al(NO₃)₃ is:

equivalents = moles x 3

Substituting the value of moles, we get:

equivalents = 0.01878 mol x 3 = 0.05634 eq

The normality can now be calculated as:

normality = equivalents / volume

Substituting the given values, we get:

normality = 0.05634 eq / 0.25 L = 0.225 N

Therefore, the normality of the solution is 0.225 N.

The molarity of the solution is defined as the number of moles of solute per liter of solution. The number of moles of Al(NO₃)₃ in 250 mL of solution is the same as the number of moles in 1 L of solution, which is 0.01878 mol. Therefore, the molarity of the solution is:

molarity = moles / volume

Substituting the given values, we get:

molarity = 0.01878 mol / 0.25 L = 0.0751 M

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Restate original Claim here. This claim was supported by the claim because the evidence showed that acidic substances have a pH value less than 7 and cause the pH paper to turn a certain color.

What is pH?

pH is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm of the concentration of hydrogen ions (H+) in a solution. pH values range from 0 to 14, where 0 is the most acidic, 7 is neutral, and 14 is the most basic. A change of one unit in pH represents a tenfold change in the concentration of hydrogen ions.

For example, from the evidence, fruit juices such as lemon juice have a pH value of around 2-3 and turn the pH paper a red color, which indicates acidity. Beverages such as coffee and soda also have a low pH value, around 4-5, and turn the pH paper a slightly red color. Cleaning products such as vinegar have a pH value of around 2-3 and turn the pH paper a red color as well.

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Al, Cu, and Zn, Al are the metals in equations 1 and 2, respectively. Since aluminium is ranked higher on the activity series than copper, it can substitute for copper in chemical reactions.

Metal and Water Reaction: An Introduction Because of the intense interactions that certain metals have with water, such potassium and sodium, they will ignite if left outside.

Magnesium is therefore the most reactive of the listed metals, and as a result, its pace of reaction will be the quickest (to react with steam). Magnesium does not react with cold water, whereas metals with strong reactivity like potassium (K), sodium (Na), and calcium (Ca) do.

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Answer:

1.525834 (1.53 when accounting for significant figures).

Explanation:

This problem relies on the Ideal Gas Law, PV = nRT, where P is pressure, V is volume, n is moles, R is a specific constant, and T is temperature. In this problem, we are solving for n, moles, so we would rewrite it as n = PV/RT. Since the units here are moles, liters, atmospheres, and kelvin, R would be the value in atmosphere liter per mole kelvin, or 0.0821. From here, you just enter the values in the fraction and calculate.

For the significant figures, I followed the measurement of 34.2 L, giving 3, although an argument could be made for 1 significant figure from 1 atm, I imagine your professor would want something more specific than 2.

Answer:

Explanation:Two pre-requisite skills needed for students to learn the process of writing balanced chemical and ionic equations are:

1. Understanding of the periodic table and elements: Students must have a solid foundation in the periodic table, including recognizing elements by their symbols and understanding their properties, groups, and electron configurations.

2. Knowledge of chemical bonding and compound formation: Students should be familiar with the different types of chemical bonds (ionic, covalent, and metallic) and know how to construct chemical formulas for compounds based on their component elements and valence electrons.

It is the least reactive of the three elements listed.  The correct order of elements from most to least reactive is:

sodium, carbon, krypton.

Sodium is a highly reactive metal and readily forms compounds with many other elements. It reacts vigorously with water and air, which is why it is stored in oil to prevent contact with moisture or oxygen.

Carbon is less reactive than sodium but can still undergo reactions, such as combustion or oxidation. Krypton, on the other hand, is a noble gas and is chemically inert, meaning it does not react with other elements under normal conditions. Therefore, it is the least reactive of the three elements listed.

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Gay-Lussac's Law-

[tex] \:\:\:\:\:\:\star\longrightarrow \underline{\sf \boxed{\sf \dfrac{P_1}{T_1}=\dfrac{P_2}{T_2}}}[/tex]

[tex] \:\:\:\:\:\:\star\longrightarrow \sf \underline{P_2=\dfrac{P_1 \:T_2}{T_1}}[/tex]

Where-

As per question, we are given -

Now that we are given all the required values, so we can put them into the formula and solve for P₂:-

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf P_2=\dfrac{P_1 \:T_2}{T_1}\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf P_2=\dfrac{6.8\times 211}{539}\\[/tex]

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf P_2 = \dfrac{1434.8}{539}\\[/tex]

[tex] \:\:\:\:\:\:\:\:\:\:\:\:\longrightarrow \sf P_2 = 2.661966.........\\[/tex]

[tex]\:\:\:\:\:\: \:\:\:\:\:\:\longrightarrow \sf\underline{ P_2 = 2.7 \:KPa}\\[/tex]

Therefore, If the temperature decreases to 211K, then the new pressure will become 2.7 KPa.

Answer:

Activation Energy

Explanation:

Activation energy is the minimum amount of energy that reactant molecules must possess in order to undergo a chemical reaction. as it is necessary to break the bonds of between the molecules of the reactants.


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1.02 mol of carbon monoxide gas will occupy a volume of approximately 22.8 liters at STP.

At STP (standard temperature and pressure), the temperature is 273.15 K (0°C) and the pressure is 1 atmosphere (atm). The molar volume of a gas at STP is 22.4 L/mol.

Using the ideal gas law, we can calculate the volume of 1.02 mol of carbon monoxide gas at STP: PV = nRT

where:

P = pressure = 1 atm

V = volume (unknown)

n = moles = 1.02 mol

R = gas constant = 0.0821 L·atm/(mol·K)

T = temperature = 273.15 K

V = (nRT)/P

putting the values,

V = (1.02 mol)(0.0821 L·atm/(mol·K))(273.15 K) / (1 atm)

V = 22.4 L/mol

V = 22.8 L

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The value of the equilibrium constant, Kc is 0.33.

The correct option is A.

The balanced chemical equation for the oxidation of NO by O2 is:

2 NO (g) + O2 (g) → 2 NO2 (g)

From the stoichiometry of the equation, we see that the mole ratio of NO to O2 consumed is 2:1. Therefore, if 3 moles of O2 are present at equilibrium, then 1.5 moles of NO have been consumed:

1.5 moles NO = 15.0 moles NO (initial) - 3.0 moles NO2 - 3.0 moles O2

Using the law of mass action, we can express the equilibrium constant (Kc) for the reaction as:

Ke = ([NO2]^2 / [NO]^2 [O2])

We know that at equilibrium, [O2] = 3.0 moles / 1.0 L = 3.0 M. To calculate [NO2], we need to use the stoichiometry of the equation and the fact that 1.5 moles of NO are consumed at equilibrium:

2 mol NO → 2 mol NO2

1.5 mol NO → 1.5 mol NO2

Therefore, [NO2] = 1.5 mol NO2 / 1.0 L = 1.5 M. Substituting the values into the equilibrium constant expression, we get:

Ke = ([NO2]^2 / [NO]^2 [O2])

Ke = (1.5 M)^2 / (1.5 M)^2 (3.0 M)

Ke = 0.333

Therefore, the answer is (a) 0.33.

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The volume of oxygen produced in the decomposition of 5 moles of KCIO3 at STP is 168 L. The balanced chemical equation for the decomposition of KCIO3 is:

2KClO3(s) → 2KCl(s) + 3O2(g)

From the equation, we can see that for every 2 moles of KCIO3, 3 moles of O2 are produced. Therefore, for 5 moles of KCIO3, the number of moles of O2 produced can be calculated as follows:

5 moles KCIO3 x (3 moles O2/2 moles KCIO3) = 7.5 moles O2

Since the conditions are given as STP (standard temperature and pressure), we can use the molar volume of a gas at STP (22.4 L/mol) to calculate the volume of O2 produced:

7.5 moles O2 x 22.4 L/mol = 168 L O2

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Explanation:

To calculate the molarity of the vinegar solution, we first need to calculate the number of moles of acetic acid present in one liter of the solution.

Since the density of the solution is 1.01 g/mL, one liter of the solution will have a mass of 1.01 kg.

The mass of acetic acid in one liter of the solution can be calculated as follows:

mass of acetic acid = 5% × 1.01 kg = 0.0505 kg

The number of moles of acetic acid can be calculated using its molar mass:

moles of acetic acid = mass of acetic acid / molar mass of acetic acid

moles of acetic acid = 0.0505 kg / 60.052 g/mol

moles of acetic acid = 0.000841 mol

Therefore, the molarity of the vinegar solution is:

molarity = moles of acetic acid / volume of solution in liters

molarity = 0.000841 mol / 1 L

molarity = 0.000841 M

So, the molarity of a 5% vinegar solution is approximately 0.000841 M.

The difference between the energy needed to break the bonds in the reactants and the energy released when new bonds are created in the products is what essentially determines the enthalpy change.

In general, a bond must be broken by a positive change in enthalpy, whereas a bond must be formed by a negative change in enthalpy. In other words, the process of breaking a bond is endothermic, whereas the process of forming a bond is exothermic.

The energy needed to break the links between the reactants less the energy released during the formation of new bonds in the products is the enthalpy of reaction.

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In terms of bonds breaking and forming, what's responsible for the enthalpy change?

Answer:

The base conjugate acid pair is NH3 and NH4+.

Answer:

time = 1.92 min

Explanation:

By knowing that

[tex]R_R = K_R [A]^{1} = \frac{[A]}{time}[/tex]  

Where: RR: rate of forward reaction, KR: rate constant, [A]: A concentration

in the previous equation, [A] is cancelled, then:

[tex]K_R = \frac{1}{time} \\ \\[/tex]


[tex]8.70\times10^{-3} = \frac{1}{time}[/tex]


Then, time = 114.94 seconds = 1.92 minutes


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Hurricane = Rapid

Volcanic eruption = Rapid

Regrowth after volcanic eruption = Gradual

Flooding = Rapid

Seasonal changes = Gradual

Oceans increasing temperature = Gradual

Global warming = Gradual

Fire = Rapid

Answer:

rapid

rapid

gradual

rapid

gradual

gradual

gradual

rapid

Explanation:

The food chain that produces elements like the crust, tomato sauce, cheese, and meat on a pizza begins with the energy that plants absorb from the sun through photosynthesis.

Green plants, algae, and some microorganisms transform solar energy into chemical energy in the form of organic compounds like carbohydrates through a process called photosynthesis. Light energy is absorbed by pigments, chiefly chlorophyll, which is present in the chloroplasts of plant cells, during photosynthesis. Next, using this energy, glucose (a form of sugar) and oxygen are produced from carbon dioxide and water.

By photosynthesis, plants use the sun's energy to create carbohydrates (like glucose). Following the consumption of these carbohydrates by herbivores, predators subsequently consume these carbs, and so on.

When it comes to a pizza, the wheat used to form the crust was probably grown in a field where it employed photosynthesis to take in energy from the sun. Like with other vegetables used as toppings, the tomatoes used to prepare the sauce were probably also grown in a field. Pizza's cheese is formed from milk, which comes from cows who eat grass and other plants that have undergone photosynthesis to receive solar energy. Last but not least, any meat added as a garnish originated from creatures that also ate vegetables for fuel.

In a sense, the sun's energy, which plants use to produce food, including the components in a pizza, is eventually harnessed by photosynthesis.

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The reaction's per cent yield is  69.5%.

We must compare the actual yield of the reaction to the theoretical yield of the reaction to get the per cent yield of the reaction.

First, we need to calculate the amount of Pb reacted using the given mass of Pb:

mass of Pb = 451.4 g

The molar mass of Pb is 207.2 g/mol, so the number of moles of Pb reacted is:

moles of Pb = mass of Pb / molar mass of Pb

moles of Pb = 451.4 g / 207.2 g/mol

moles of Pb = 2.179 mol

The theoretical yield of PbO can be calculated using the molar mass of PbO:

mass of PbO = moles of PbO × molar mass of PbO

mass of PbO = 2.179 mol × 223.2 g/mol

mass of PbO = 486.6 g

Therefore, the theoretical yield of PbO is 486.6 g.

The per cent yield of the reaction is:

per cent yield = (actual yield / theoretical yield) × 100%

per cent yield = (338.4 g / 486.6 g) × 100%

percent yield = 69.5%

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The alcohol and water molecules sharing the same space leads to a more compact arrangement of the molecules in the combination, which is the best explanation for the observed drop in volume.

In this illustration, adding water to alcohol results in a final volume that is roughly 10% lower than the combined volumes of the two liquids. The "vanishing volume" results from variations in how the solvent molecules are packed in the mixture compared to the pure components.

Alcohol molecules slide into the spaces between the water molecules as it dissolves, reducing the volume.

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If 50cm³ of alcohol is mixed with 50cm³ of water. The volume of the mixture is 97cm³. What is the best explanation for this observation?

A. Water evaporates leading to decrease in volume of the mixture

B. Water and alcohol molecules react and form a compact solution

C. Alcohol being volatile evaporates and decreases the volume of the mixture

D. The alcohol and water molecules sharing the same space leads to the decrease in volume of the mixture

The order of the arrangement of the wavelengths from strongest to weakest is;

447 > 492 > 588 > 668

The wavelength is a fundamental property of a wave and is related to its frequency and speed through the equation:

wavelength = speed of light / frequency

where the speed of light is approximately 299,792,458 meters per second (m/s) and the frequency is measured in Hertz (Hz), which represents the number of cycles per second.

The wavelength is an important concept in many areas of physics, including optics, acoustics, and electromagnetic radiation.

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One mole of glucose burns to produce several gases. [tex]6600kJ[/tex] of power. Another way to put it is that the burning of glucose releases  [tex]6600KJ/mol[/tex]  thermal energy.

A chemical reaction between two or more substances, typically containing oxygen, is called combustion. It results in the production of light and heat in the form of a flame.

The correct chemical formula for the burning of glucose

[tex]C6H12O6 + 6O2 \rightarrow  6CO2 + 6H2O[/tex]

We can determine the change in enthalpy for this reaction by using the values provided for the enthalpies of formation of the reactants and products:

Reactants:

[tex]C_6H_1_2O_6[/tex] : not given

[tex]O2: -498 kJ/mol \times 6 = -2988 kJ/mol[/tex]

Products:

[tex]CO_2[/tex]: not given

[tex]H2O -1598 kJ/mol \times 6 = -9588 kJ/mol[/tex]

[tex]\Delta H = (\epsilon products) - (\epsilon reactants)[/tex]

[tex]\Delta H = (-9588 kJ/mol + 0) - (0 + -2988 kJ/mol)[/tex]

[tex]\Delta H = -6600 kJ/mol[/tex]

Therefore, One mole of glucose burns to produce several gases. [tex]6600kJ[/tex] of power. Another way to put it is that the burning of glucose releases  [tex]6600KJ/mol[/tex]  thermal energy.

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Answer:

0.0924 mol Al₂O₃ = 9.42 g

0.0165 mol Be₃Al₂(SiO₃)₆ = 8.87 g

0.0380 mol MgAl₂(SiO₄)₃ = 13.5 g

Explanation:

mass = number of moles * molar mass

(PART A) The molar mass of Al₂O₃ is 101.96 g/mol. To find the mass in grams of Al₂O₃ that are in 0.0924 moles:

0.0924 mol * 101.96 g/mol = 9.42 g

(PART B) The molar mass of Be₃Al₂(SiO₃)₆ is 537.51 g/mol. To calculate the mass in grams of 0.0165 moles of Be₃Al₂(SiO₃)₆:

0.0165 mol * 537.51 g/mol = 8.87 g

(PART C) The molar mass of MgAl₂(SiO₄)₃ is 354.52 g/mol. To calculate the mass in grams of 0.0380 moles of MgAl₂(SiO₄)₃:

0.0380 mol * 354.52 g/mol = 13.5 g

The mass of ruby in grams is 9.43 g.
The mass of emerald in grams is 8.87 g.
The mass of garnet in grams is 16.56 g.

To calculate the mass of a compound in grams, we need to know the molar mass of the compound, which is the sum of the atomic masses of all the atoms in the formula. Once we know the molar mass, we can use the formula:

mass in grams = number of moles x molar mass

where the number of moles is given and the molar mass is calculated from the formula. In each case, we plug in the numbers and perform the calculation to obtain the mass in grams.

PART A: molar mass of Al₂O₃ is 101.96 g/mol (2 x 26.98 g/mol for Al and 3 x 16.00 g/mol for O).

As a result, the ruby mass in grammes is:

0.0924 moles x 101.96 g/mol = 9.43 g

PART B: The molar mass of Be₃Al₂(SiO₃)₆ is 537.54 g/mol (3 x 9.01 g/mol for Be, 2 x 26.98 g/mol for Al, 6 x 28.09 g/mol for SiO₃).

Therefore, The mass of an emerald in gram is :

0.0165 moles x 537.54 g/mol = 8.87 g

PART C: The molar mass of MgAl₂(SiO₄)₃ is 435.52 g/mol (1 x 24.31 g/mol for Mg, 2 x 26.98 g/mol for Al, 3 x 60.08 g/mol for SiO₄).

Therefore, the garnet mass in grams is :

0.0380 moles x 435.52 g/mol = 16.56 g

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When exposed to lead at high levels, the brain and central nervous system are attacked, resulting in unconsciousness, convulsions, and even death.

Lead poisoning affects up to 800 million children worldwide, or close to one third of all children. Lead has a negative impact on a child's developing brain, leading to diminished IQ, behavioral difficulties, and learning issues that can lower potential earnings as an adult.

The Safe Drinking Water Act (SDWA) reduced the maximum permitted lead level, or "lead-free" content, to a weighted average of 0.25 percent measured throughout the wetted surfaces of pipes, pipe fittings, plumbing fixtures, and fixtures, and 0.2 percent for solder and flux.

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What are the toxic effects of lead? How can it affect the human body?

10.0 mL of 0.115 M [tex]H_2SO_4[/tex] needs to be neutralised with 0.370 mL of a 0.310 M NaOH solution.

Calculate how much 0.310 M NaOH is required to neutralise 10.0 mL of 0.115 M [tex]H_2SO_4[/tex] in millilitres, we can apply the following formula:

Moles of [tex]H_2SO_4[/tex] = (Concentration of [tex]H_2SO_4[/tex])(Volume of [tex]H_2SO_4[/tex])

Moles of [tex]H_2SO_4[/tex] = (0.115 M)(10.0 mL) = 0.00115 moles

Since the reaction is 1 mole of [tex]H_2SO_4[/tex] to 2 moles of NaOH, we must have 0.00115 moles of NaOH to neutralize the [tex]H_2SO_4[/tex].

Moles of NaOH = (Concentration of NaOH)(Volume of NaOH)

0.00115 moles = (0.310 M)(Volume of NaOH)

Volume of NaOH =[tex]\frac{ 0.00115 moles}{0.310 M } = 0.370 mL[/tex]

Therefore, 0.370 mL of a 0.310 M NaOH solution are needed to neutralize 10.0 mL of 0.115 M [tex]H_2SO_4[/tex].

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