Consider:
2Al (s) + 3Cl2 (g) ----> 2AlCl3 (s) ΔH=-1390.81 kJ

Which of the following correctly describes he magnitude and direction of the enthalpy change when 10.0g of AlCl3 forms?

a. 104.4 kJ, exothermic
b. 52.2 kJ, exothermic
c. 26.1 kJ, exothermic
d. 52.2 kJ, endothermic
e. 26.1 kJ, endothermic

Answers

Answer 1

Answer:

The answer is B.

Explanation:

1 mole of AlCl3 = 27 + 3*35.5 grams = 133.5 grams

1 mole / 133.5 = x / 10         Cross multiply

133.5 x = 1 * 10

x = 10 / 133.5

x = 0.0749 moles

Delta H when written the way it is, is on the left side and since it is negative, the reaction must give away 1390.81 kj. The reaction is exothermic.

So now you get the answer between AB and C by setting up a ratio.

2/0.0749 = -1390.81 / x          Cross multiply

2x = 0.0749 * -1390.81

2x =- 104.18                             Divide both sides by 2

2x//2 = -104.18 / 2

x = -52.09

B


Related Questions

what is the difference between exergonic and exothermic reactions?​

Answers

Answer:

An exergonic reaction is a type of chemical reaction that releases free energy to the surroundings. The final state of this reaction is less than its initial state. ... “Exothermic” literally means “outside heating” while “exergonic” literally means “outside work.”

Explanation:

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An exothermic reaction is where energy is given off as heat and an exergonic reaction is where energy is given off as light.

Can you give a definition of what Sodium Hydroxide

Answers

Answer:

Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na⁺ and hydroxide anions OH⁻

Explanation:

Also can you mark me as brainliest.

Calculate the number of days after the explosion for a sample of iodine-131 to go from 100%
iodine-131 to less than 1% iodine-131. Complete chart.

Answers

It will take 56 days to go from 100% iodine-131 to less than 1% iodine-131.

From the table, we can see that the half life of iodine-131 is 8 days. We can see that it takes 8 days to have 50% of iodine-131

After 16 days, we will have 25 % of iodine-131

After 24 days, we will have 12.5 % of iodine-131

After 32 days, we will have 6.25% of  iodine-131

After 40 days, we will have 3.125% of  iodine-131

After 48 days, we will have 1.5625% of iodine-131

After 56 days, we will have 0.78125% of iodine-131

After 56 days, the percentage of iodine-131 drops to less than 1%.

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A 3.90 L sealed vessel under vacuum is filled with 6.40 g of fluorine gas. What is the pressure (in kPa) of the vessel at 25.0 ⁰C ?

Answers

From the ideal gas law, the pressure of the gas is 106 kPa.

First we must obtain the number of moles of the gas;

Number of moles = mass/molar mass

Molar mass of fluorine gas = 38 g/mol

Number of moles of F2 = 6.40 g/38 g/mol = 0.168 moles

Using the ideal gas equation;

PV = nRT

P = ?

V = 3.90 L

n =  0.168 moles

T = 25.0 ⁰C + 273 = 296 K

R = 8.314  kPa L K-1 mol-1

Substituting values;

P = nRT/V

P =  0.168 moles × 8.314  kPa L K-1 mol-1 ×  296 K/3.90 L

P = 106 kPa

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The pressure of the vessel at a temperature of 25 °C is 106.73 KPa

We'll begin by calculating the number of mole of fluorine gas. This can be obtained as follow:

Mass of F₂ = 6.40 g

Molar mass of F₂ = 19 × 2 = 38 g/mol

Mole of F₂ =?

Mole = mass / molar mass

Mole of F₂ = 6.40 / 38

Mole of F₂ = 0.168 mole

Finally, we shall determine the pressure. This can be obtained as follow:

Volume (V) = 3.90 L

Temperature (T) =  25.0 °C = 25 + 273 = 298 K

Mole of F₂ (n) = 0.168 mole

Gas constant (R) = 8.314 L.KPa/Kmol

Pressure (P) =?

PV = nRT

P × 3.9 = 0.168 × 8.314 × 298

P × 3.9 = 416.232096

Divide both side by 3.90

P = 416.232096 / 3.90

P = 106.73 KPa

Therefore, the pressure of the vessel is 106.73 KPa

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(iii) Explain why magnesium chloride has a high melting point.

Answers

Answer:

magnesium chlorides are solids with high melting and boiling points because of the large amount of heat which is needed to break the strong ionic attractions.

Explanation:

These magnesium ions have more than one charge (2+). These highly charged ions will attract other ions more strongly than ions with one charge, therefore more energy will be needed to overcome the electrostatic forces of attraction and so the melting points will be higher.

Which statement describes the bonds in nitrate (NO3-)?

A) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.

B) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is nonpolar covalent.

C) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is ionic.

D) Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with nitrogen pulling the electrons toward it.

Answers

The bond in NO3- ion is polar covalent and oxygen pulls the electrons.

A polar covalent bond is formed when there is a significant difference in electronegativity between covalently bonded atoms.

Such bonds are said to be polar covalent with the electron density tilted towards one of the bonding atoms.

In NO3-, Nitrogen and oxygen have an electronegativity difference of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.

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The answer is A, Nitrogen and oxygen have an electronegativity of 0.5, so the bond is polar covalent, with oxygen pulling the electrons toward it.

Electronegativity is defined as, a value that describes the relative strength with which an atom of an element attracts electrons to itself in a chemical bond. Moreover, electronegativity can be used to define a bond.

A electronegativity of 0.5-1.7 is determined to be a polar covalent bond, thus the bonds in nitrate is polar covalent.

We know that electronegativity increases on the periodic table across a period, but decreases down a group. Thus, oxygen has a greater electronegativity than nitrogen.

Alka-Seltzer is pure NaHCO3
True or false?

Answers

Answer:

falso

Explanation:

A force of 500 N acts over an area of 10 m2. Use the
formula to calculate the pressure.

Answers

Answer:

50Pa

Explanation:

pressure= force/area

= 500N/10m2

= 50Pa

A compound's properties are different than the properties of the elements that make it up.

A)True
B)False

Answers

The answer is True because elements in a compound combine and become an entirely different substance with its own unique properties.

According to the law of conservation of matter, which statement about chemical reactions is true? A. Atoms cannot be created or destroyed by chemical reactions. B. Atoms are created by some reactions and destroyed by others. C. Energy is created as atoms are destroyed in chemical reactions. D. Every atom destroyed in a chemical reaction must be replaced.

Answers

The answer is number A)

When doing medical research with human subjects, which four limitations are unavoidable?

Answers

Answer:

Answer

The limitations are-

1. Privacy of the individuals involved in the research process.

2. Physical and psychological risks should be minimized

3. The subjects should be chosen equitably

4. Only reasonable exposure to risks is admissible.

Explanation

The privacy of the individuals involved in the research must be taken into consideration. This will ensure safety of patient data and information. The risk of physical and physiological well being of the person must be taken into consideration in such a research. In addition to that, the subject must be made to understand every procedure and the risks involved before testing. Moreover, only minimal exposure to risks is allowed and must have been previously tested in animals to avoid deaths.

What is the lead concentration of a saturated solution of lead(II) sulfate containing 0.020 M Na2SO4? Ksp for PbSO4 = 6.3x10-7.

Answers

Answer:

i want to help but  i   d   k. the answer :( sorry i couldnt help

Explanation:

. The atomic number of a newly discovered element is found to be 128, and its mass number is 279.
How many protons, neutrons, and electrons are found in an ion of this element bearing a charge of
5−?

Answers

Use APEMAN strategy

A-128
P-128
E-128
M-279
A-128
N-151

Hope this strategy helps

Can you help me solve this ?

Answers

All of the above are true

Have a great day!

what happens to a circuits resistance (R), voltage (V), and current (I) when you increase the diameter of the wire in the circuit?

a. R increases, V is constant, I increases

b. R decreases, V is constant, I increases

c. R decreases, V increases, I increases

d. R increases, V decreases, I decreases

Answers

Answer:

b. R decreases, V is constant, I increases

Explanation:

when we increase the diameter of wire increases ,resistance decreases and current increases.Therefore, the option is b.  

Resistance is an electrical quantity which opposes the electric current in the circuit. Resistance is directly proportional to the length of the wire and inversely proportional to the diameter of the wire. If length of wire increases resistance will increases and if the diameter of the wire increase resistance will decreases.

                                R = ρ L/A

Here ρ is the resistivity

        L is the length of the wire

        A  is the cross-sectional area of wire/diameter of the wire

Voltage is the potential difference between two terminals of voltage source. Current is the flow of electrons in the circuit. Voltage is the product of current and resistance.

                              V=IR

Rewrite the above equation interms of current

                              I=V/R

From the above equation we can say that current is inversly proportional to the resistance.Therefore,the correct option is b.

Learn more about,resistance

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Please solve this question

Answers

Answer:

what question?

Explanation:

Why do you think dark surfaces absorb radiation better than light surfaces?

Answers

Your answer→ The lighter side absorbs less of the incident light, reflecting some of the energy. Darker materials also emit radiation more readily than light-colored materials, so they cool faster.

To solve this we must be knowing each and every concept related to radiation. Therefore, dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.

What is radiation?

According to the energy of the emitted particles, radiation is frequently classified as being either ionizing or non-ionizing. More than 10 eV is often carried by ionizing radiation, which is sufficient to ionize atoms as well as molecules and rupture chemical bonds.

The word refers to radiation having an energy level high enough to ionize atoms, or to remove electrons from atoms to produce ions. Whenever an electron is removed from an atom's electron shell, or, as we may say, when it is "tried to knock out," the action of ionization takes place. Dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.

Therefore, dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.

To know more about radiation

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#SPJ2

wat are the dangers of chemicals in the laboratory​

Answers

chemicals can physically hurt you, damage you, or cause fires.

can someone help me please ... god will bless u if u help...it is very urgent... i only have 1hr to answer this question​

Answers

Answer:

iuiwusiwuiqihihiuwusbhwubduywbduywbudb me no esspanlo

Explanation:

niuniniuniuniun

5. A student measures the mass of an object three times on a balance in order to calculate the objects
density. The recorded masses are 70.21 g, 64.55 g, and 74.70 g. The accepted value for the mass of
the object is 70.21 g.
a. Are these measurements accurate? Why or why not?
b. Are the measurements precise? Why or why not?

Answers

Answer:

This is not chemistry this is physics

helppppppppppppppppppppppppp

Answers

True

All matter is made up of atoms.

im guessing it probably true

What mineral is composed of sodium chloride (NaCl)?

Answers

Answer:

Salt

Explanation:

The mineral form halite , or rock salt is sometimes called common salt

The change in internal energy for the combustion of cyclohexanol (C6H12O) is -890.7 Kcal per mole. A .708 g sample of cyclohexanol undergoes complete combustion in a bomb calorimeter that has a heat capacity of 2.70 Kcal per degree C. What is the final temperature of the water in the calorimeter if the initial water temperature is 27C?

Answers

The final temperature in the calorimeter, with a heat capacity of 2.70 kcal/°C, internal energy for the combustion of cyclohexanol (C₆H₁₂O) of -890.7 kcal/mol and initial temperature of 27°C, is 29.33 °C.

We can find the final temperature of the water in the calorimeter with the following equation:

[tex]\Delta E = -C\Delta T = -C(T_{f} - T_{i})[/tex]    (1)

Where:

ΔE: is the change in internal energy for the combustion of C₆H₁₂O = -890.7 Kcal/mol

C: is the heat capacity of the calorimeter = 2.70 Kcal/°C

[tex]T_{f}[/tex]: is the final temperature =?

[tex]T_{i}[/tex]: is the initial temperature = 27 °C

By solving equation (1) for [tex]T_{f}[/tex], we have:

[tex] T_{f} = -\frac{\Delta E}{C} + T_{i} [/tex]

[tex]T_{f} = -\frac{-890.7 \frac{kcal}{mol\: C_{6}H_{12}O}*\frac{1 mol \: C_{6}H_{12}O}{100.158 g \: C_{6}H_{12}O}*0.708 g \: C_{6}H_{12}O}{2.70 kcal/^{\circ}C} + 27 ^{\circ}C = 29.33 ^{\circ}C[/tex]  

Therefore, the final temperature of the water is 29.33 °C.

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Câu 15: Nguyên tử X nặng gấp 2 lần nguyên tử cacbon. Nguyên tử X đó có nguyên tử khối và

kí hiệu hóa học là

A. 24_Mg. B. 16_O C. 56_Fe D. 32_S

Answers

Answer:

A

Explanation:

If you have 4.01 g of H2, how many grams of NH3 can be produced?

Answers

Answer:

136.5886g of NH3

Explanation:

N2 + 3H2 = 2NH3

The mass of the N2 = 4.01

3H2 has a 2/1 ratio

This means the mass of 3H2 is twice as much as N2.

NH3= 2*N2 = 2*4.01 = 8.02 of NH3

Then, by multiplying the mass by MX (17.031)

8.02*17.031=136.5886g can be produced. Round it if needed.

5. The density of a gas is lower than the density of a liquid because:
a. gas atoms are smaller than liquid atoms.
b. gas atoms are larger than liquid atoms
c. atoms in a gas are farther apart than atoms in a liquid.
d. atoms in a gas are closer together than atoms in a liquid

Answers

Answer:

c

Explanation:

the gas is further apart and the liquid is closer together

Which has more calories: table sugar or aspartame?

Answers

Answer:

Aspartame produces 4 kilocalories of energy per gram when metabolized, sucrose (table sugar) produces 3.9 kilocalories. However, aspartame is approximately 200 times sweeter than sucrose, so it is consumed in much smaller doses.

Explanation:

Answer is Aspartame.

How many mL of 1.76 M sodium hydroxide solution (strong base) must be added to 0.75
Macetic acid to make 683 mLa pH 49 buffer? (pka of acetic acid is 4.76)

Answers

Answer: Special care is required to prepare a solution of sodium hydroxide or NaOH in water because considerable heat is liberated by the exothermic reaction. The solution may splatter or boil. Here is how to make a sodium hydroxide solution safely, along with recipes for several common concentrations of NaOH solution.

Explanation:

Hope this helps!

PLS HELP WORTH 25 POINTS WILL MARK BRAINLIEST IF CORRECT
Examine the false statement. When pressure is added to a reaction at chemical equilibrium, the reaction responds by increasing the amount of pressure it exerts on its surroundings. Select the rewording that makes the statement true.

A. When pressure is added to a reaction at chemical equilibrium, the reaction responds by increasing the rate of reaction, which will decrease the number of particles and offset the pressure.

B. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it exerts on its surroundings.

C. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by increasing the rate of reaction, which will decrease the number of particles and increase the pressure.

D. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it releases to its surroundings.


E. When pressure is added to a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it absorbs from its surroundings.

IT'S NOT C OR E

Answers

Answer:

A i think. Good luck!!!!


The electronic transition in a hydrogen atom from n = 6 to n = 3 emits electromagnetic radiation having a higher frequency than a transition
from n = 5 to n = 3

Answers

Hoy !have a great day
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A drilling machine can drill 12 holes in 6 minutes. If the machine drills holes at a constant speed, it can drill holes in 25 minutes. HELPPP Help Please!! Ill Give Brainliest!On a coordinate grid, point A is located in the first quadrant. Point B is located at (negative 1 over 2, 2).Point C is a reflection of point B across the y-axis. Which graph shows these three points? A coordinate grid from negative 3 to positive 3 on both axes is drawn in increments of 1 over 2. Point A is plotted 4 grid lines to the right of the y-axis and 1 grid line above the axis. Point B is plotted at 1 grid line to the left of the y-axis and 4 grid lines above the x-axis. Point C is plotted at 1 grid line to the left of the y-axis and 4 grid lines below the x-axis. A coordinate grid from negative 3 to positive 3 on both axes is drawn in increments of 1 over 2. Point A is plotted 4 grid lines to the right of the y-axis and 1 grid line above the x-axis. Point B is plotted at 1 grid line to the left of the y-axis and 4 grid lines above the x-axis. Point C is plotted at 1 grid line to the right of the y-axis and 4 grid lines above the x-axis. A coordinate grid from negative 3 to positive 3 on both axes is drawn in increments of 1 over 2. Point A is plotted 2 grid lines to the left of the y-axis and 4 grid lines above the axis. Point B is plotted at 1 grid line to the right of the y-axis and 4 grid lines above the x-axis. Point C is plotted at 1 grid line to the left of the y-axis and 4 grid lines below the x-axis. A coordinate grid from negative 3 to positive 3 on both axes is drawn in increments of 1 over 2. Point A is plotted 2 grid lines to the left of the y-axis and 4 grid lines above the axis. Point B is plotted at 1 grid line to the right of the y-axis and 4 grid lines above the x-axis. Point C is plotted at 1 grid line to the right of the y-axis and 4 grid lines below the x-axis. Which of these inventions is the first microscope? Pls help will give brainiest!!! Grandpa has a barrel of apples. 2/5 of the apple are rotten. 24 of the apples are good. How many apples are there in total? can someone help me with these:2: 30210^-8. 3:6.810^3 . 4 : 9.110^-7. 5: 2.3 10^4 please need this by 12:10 pm Write=1\frac{5}{7}[as an improper fraction. Find the x-intercept and y-intercept of the line and then graph the equation-4x+2y=-4 Is this sentence written correctly?The teacher warned us, "that a suprise quiz was coming." name three things mexican do to celebrate day of the dead When converted to a household measurement, 9 kilograms is approximately equal to a please please please answer ill pay you First one to answer will be marked brainliest A sea lion jumped out of the water to a height of 3 feet above sea level. The number line shows the location of the sea lion at the top of its jump. From this location, the sea lion dove down 9 feet. Describe how to use the number line to find the new location of the sea lion. Gandalf's most important advice isnot to waste arrowsnot to stray from the pathto keep their spirits up explain the roles played by second world war in decolonisation of kenya 2 +2 - 6 + 8 and then 2 HELP FAST PLEASE WILL MARK BRAINLIEST IF GIVEN AN EXPLANATION WITH ANSWER :) WRONG OR COPY & PASTED ANSWERS WILL BE REPORTED IMMEDIATELY Which of the following was probably thereason for the need to ensure domestictranquility"?(1) The Revolutionary War had just ended.(2) Shays's Rebellion and other uprisingswere taking place.(3) The Declaration of Independence hadbeen signed(4) Spain and Britain refused to trade withthe states.(5) Americans were against taxation withoutrepresentation. a line with the slope of -3 passes through (-8, p) and (2, 3p). Find the value of p The slope is negative in the graph as you move from left to right the line of the graph is going