CHEM 103 UW Madison Exam 2 Review

This effect occurs when infrared radiation that is emitted from the earth's surface is trapped by gases (H2O, CO2, CH4, etc) that also absorb and re-emit this infrared radiation.

green house effect

Describe how to find the partial pressure of a gas.

multiply the mole fraction of the gas by the total pressure of all gases or multiply the number of mules by R and the temperature in K then divide by the volume in L

What is the enthalpy of formation of liquid bromine at 25 degrees C?

zero

Melting of a substance requires using the ___ (∆Hfus/∆Hvap) value.

∆Hfus

92 mL of sulfur dioxide gas is mixed in a sealed syringe (with a movable plunger) with 86 mL of oxygen gas to give a total of 178 mL of gas. What volume does the O2 gas occupy in the syringe once the two gases are mixed?

178 mL

Write the balanced chemical equation for the reaction of solid aluminum with aqueous hydrochloric acid to produce aqueous aluminum chloride and hydrogen gas. Explain why a temp change would be observed.

2 Al(s) + 6 HCl(aq) = 2 AlCl3(aq) + 3 H2(g) Energy is released by the chemical reaction and energy is absorbed by the water (or solution).

If a gas is at 273.15 K and 1 atm (101.325 kPa), what is its volume?

22.4 L

In terms of temperature T, what is the average kinetic energy of one mole of Xenon atoms?

3/2(RT)

On a graph, how would it be displayed if a gas's molecules were at higher speeds due to higher temperatures?

the distribution would shift right and flattens

List extensive properties.

- amount (n) - volume - mass - heat capacity - internal energy - enthalpy - thermal energy

List intensive properties.

- chemical potential - color - density - BP/MP - pressure - specific heat capacity - temperature

List exothermic reactions.

- combustion - neutralization - rusting - Na + Cl2 = 2NaCl - freezing water - snow forming inside clouds - respiration - rain forming from water vapor in clouds - burning sugar - condensation

List endothermic reactions.

- dissolving ammonium chloride in water - thermal decomposition - photosynthesis - melting - sublimation - evaporation

Describe the 4 assumptions of kinetic molecular theory.

1) Gases consist of tiny particles that move at different speeds and in every possible direction; they are in constant motion. 2) The size of gas particles is much smaller than the distances between them. 3) There is no force of attraction or repulsion between gas particles. 4) They undergo elastic collisions with the walls of the container and with each other.

List the 3 properties of an ideal gas.

1) Particles have no volume. 2) Particles exert no forces on each other. 3) Particles are in constant motion.

If the fraction of methane (CH4) molecules in air is 1.8 ppm (parts per million), how many molecules of methane are in 10.0 liters of air 1.00 atm at 25 °C? State the assumptions that you made about the above gas sample that allowed you to apply the equation to solve the problem.

1. Assume gas particles have no volume 2. Assume gas particles have no attractions for each other

If N2 gas at 3.0 atm in 1 L combines with Ar gas at 5.0 atm in 0.5 L, find the ratio of partial pressure of N2:Ar.

Step 1: multiply the pressure of N2 (3) by Vi of N2 (1) divided by Vf (1+0.5) Step 2: multiply the pressure of Ar (5) by Vi of Ar (0.5) divided by Vf (1.5) Step 3: divide Step 1 value by Step 2 value

Assume your hand and the reactants all start at the same temperature. As each process occurs, think about whether your hand feels warmer or cooler as the process (or processes) occur. Sweat evaporating from your hand makes your hands feel ___ (warm/cold).

cold

Assume your hand and the reactants all start at the same temperature. As each process occurs, think about whether your hand feels warmer or cooler as the process (or processes) occur. The melting of ice on your hand makes your hands feel ___ (warm/cold).

cold

Which of the following is a characteristics of a greenhouse gas? a) Absorbs infrared (IR) light. b) Has a high density. c) Absorbs green light. d) Reacts readily with other gases.

Absorbs infrared light.

Which of the following processes are exothermic: 1) Adding magnesium to a solution of HCl 2) Water freezing on a cherry blossom 3) The reaction of H2 and O2 gases to form water

All

Which of the following are false for an ideal gas? Select all that apply. a) The volume of the gas is negligible. b) All particles in a sample at 300 Kelvin are moving at identical speeds. c) The attraction between gas particles is negligible. d) The sample will be colorless.

All particles in a sample at 300 Kelvin are moving at identical speeds. The sample will be colorless.

CaCl2 dissolves in water exothermically. Which of the following experiments produces the largest increase of thermal energy? Why? a) Dissolving 1.0 g CaCl2 in 100 mL of water. b) Dissolving 2.0 g CaCl2 in 100 mL of water. c) Dissolving 1.5 g CaCl2 in 50 mL of water. d) Dissolving 0.50 g CaCl2 in 150 mL of water. e) They would all produce the same quantity of thermal energy.

Dissolving 2.0 g CaCl2 in 100 mL of water. Since q = mcT, a larger m would result in a larger q.

If the same amount of energy in the form of heat is added to 5.00 g samples of each metal listed below, which metal will undergo the largest temperature change? Why? Metal Specific Heat Capacity: Ni 0.440 Al 0.897 Cu 0.385 Fe 0.449 Mg 1.017

Cu If energy in the form of heat (q) and mass (m) are constant, the substance with the lowest specific heat will have the largest temp change

According to experiments concerned with the photoelectric effect, which of the following would increase the kinetic energy of an electron ejected from a metal surface? i. Increasing the number of photons of light striking the surface. ii. Decreasing the frequency of the light striking the surface. iii. Decreasing the wavelength of the light striking the surface.

Decreasing the wavelength of the light striking the surface.

CaCl2 dissolves in water exothermically. Which of the following experiments produces the largest increase of thermal energy? Why? a) Dissolving 1.0 g CaCl2 in 100 mL of water. b) Dissolving 2.0 g CaCl2 in 100 mL of water. c) Dissolving 1.5 g CaCl2 in 50 mL of water. d) Dissolving 0.50 g CaCl2 in 150 mL of water. e) They would all produce the same quantity of thermal energy.

Dissolving 0.50 g CaCl2 in 150 mL of water. Since q = mcT, a smaller m would result in a smaller q.

CaCl2 dissolves in water exothermically. If the reaction takes place in a Styrofoam cup which of the following experiments would produce the largest temperature change? a) Dissolving 1.0 g CaCl2 in 100 mL of water. b) Dissolving 2.0 g CaCl2 in 100 mL of water. c) Dissolving 1.5 g CaCl2 in 50 mL of water. d) Dissolving 0.50 g CaCl2 in 150 mL of water. e) The temperature change would be the same in all cases.

Dissolving 1.5 g CaCl2 in 50 mL of water.

All flasks have the same conditions: volume is 2.50 L, pressure in each flask is 662 mmHg, and the temperature is 105 degrees C. Flask A has Cl2, flask B has Xe, flask C has H2. Which is true? (i) Each flask contains the same number of moles of gas. (ii) Each flask contains the same mass of gas. (iii) The rms speed for each gas is the same.

Each flask contains the same number of moles of gas

A sample of water is in a closed container with variable volume. It is heated to its boiling point and allowed to boil. The sample is then allowed to condense back into liquid water, and then it is cooled back to its initial temperature. T/F; Even if the process took place at constant pressure, no work was done during any step in the process.

False

A sample of water is in a closed container with variable volume. It is heated to its boiling point and allowed to boil. The sample is then allowed to condense back into liquid water, and then it is cooled back to its initial temperature. T/F; H for the entire process, start to finish, is <0.

False

A sample of water is in a closed container with variable volume. It is heated to its boiling point and allowed to boil. The sample is then allowed to condense back into liquid water, and then it is cooled back to its initial temperature. T/F; No heat is exchanged with surroundings during the process.

False

A sample of water is in a closed container with variable volume. It is heated to its boiling point and allowed to boil. The sample is then allowed to condense back into liquid water, and then it is cooled back to its initial temperature. T/F; When the entire process is considered, the change in energy is greater than the change in enthalpy.

False

If the same amount of energy in the form of heat is added to 5.00 g samples of each metal listed below, which metal will undergo the smallest temperature change? Why? Metal Specific Heat Capacity: Ni 0.440 Al 0.897 Cu 0.385 Fe 0.449 Mg 1.017

Mg If energy in the form of heat (q) and mass (m) are constant, the substance with the highest specific heat will have the smallest temp change

Select the TRUE statements related to the electromagnetic spectrum i. Microwaves have longer wavelengths than x‐rays ii. Radio waves have higher frequency than ultraviolet radiation iii. Red light has higher energy than blue light

Microwaves have longer wavelengths than x‐rays

The diffusion rate of an unknown gas is measured to be 31.50 mL/min. Under identical conditions, the diffusion rate of oxygen gas is measured to be 30.50 mL/min. Hint: diffusion rate is directly related to velocity. Determine the identity of the unknown gas from the following options and explain why. a. CH4 b. CO c. NO d. CO2 e. NO2

NO since molar mass is 30.01 g/mol

Which of the following variables for a gas is/are inversely related to each other? (i) Pressure and Volume (ii) Pressure and Temperature (iii) Pressure and Number of Moles

Pressure and Volume

Select the FALSE statements related to the electromagnetic spectrum i. Microwaves have longer wavelengths than x‐rays ii. Radio waves have higher frequency than ultraviolet radiation iii. Red light has higher energy than blue light

Radio waves have higher frequency than ultraviolet radiation Red light has higher energy than blue light

92 mL of sulfur dioxide gas is mixed in a sealed syringe (with a movable plunger) with 86 mL of oxygen gas to give a total of 178 mL of gas. 2SO2 + O2 = 2SO3 If immediately after the completion of the reaction of SO2 and O2 the volume of the gas in the syringe was lower than that calculated (132 mL), would this imply the reaction was exothermic or endothermic? Explain.

Since the volume decreased, the temperature must have decreased (when pressure and moles are constant), so the reaction must have been endothermic.

92 mL of sulfur dioxide gas is mixed in a sealed syringe (with a movable plunger) with 86 mL of oxygen gas to give a total of 178 mL of gas. 2SO2 + O2 = 2SO3 If immediately after the completion of the reaction of SO2 and O2 the volume of the gas in the syringe was higher than that calculated (132 mL), would this imply the reaction was exothermic or endothermic? Explain.

Since the volume increased, the temperature must have increased (when pressure and moles are constant), so the reaction must have been exothermic.

If the fraction of methane (CH4) molecules in air is 1.8 ppm (parts per million), how many molecules of methane are in 10.0 liters of air 1.00 atm at 25 °C?

Step 1: Find equation (n = PV / RT) Step 2: convert C to K Step 3: input values into equation Step 4: multiply Step 3 value by 1.8 mol of CH4 and divide by 1*10^6 mol air) Step 5: multiply Step 4 value by Avogadro's number (6.022*10^23)

Describe how you would find the root-mean-square speed of H2S at 26 degrees C in m/s.

Step 1: Find equation (square root(3RT / M)) Step 2: Find molar mass of H2S Step 3: identify constant (R = 8.314) Step 4: Input values and calculate

Based on the data, determine the heat of reaction (H) in kJ/mol Al. 2 Al(s) + 6 HCl(aq) = 2 AlCl3(aq) + 3 H2(g) Mass of Al(s) = 0.0429 g Mass of HCl(aq) = 10.000 g csoln = 4.184 J/g°C Pressure in lab = 715 mm Hg Initial temperature = 25.4 °C Final temperature = 45 °C

Step 1: Set up equation (qrxn = -qsoln = -msolncT) Step 2: Input values and calculate (-10*4.184*19.6) Step 3: divide Step 2 value by mol of Al (mass of Al divided by molar mass of Al) Step 4: convert Step 3 value to kJ/mol by dividing by 1000

If you add 1000 mL of water to 100 mL of a 1.00 M solution of K2CrO4, describe how you would find the molarity (M) of the solution.

Step 1: add volumes together and convert to L Step 2: divided 1.00 by Step 1 value

All flasks have the same conditions: volume is 2.50 L, pressure in each flask is 662 mmHg, and the temperature is 105 degrees C. Flask A has Cl2, flask B has Xe, flask C has H2. Describe how you would find the density of the gas in flask B.

Step 1: convert 662 mmhg to atm Step 2: multiply the Step 1 value by the molar mass of Xe Step 3: divide the Step 2 value by R (0.08206) Step 4: convert 105 degrees C to K Step 5: divide Step 3 value by Step 4 value

How much heat is released when 10.0 g hydrogen gas is burned in the presence of 10.0 g oxygen gas? Describe how to solve. 2 H2(g) + O2(g) ⟶ 2 H2O(l) + 483.6 kJ

Step 1: convert g of H2 to mol of H2 (divide mass of H2 by molar mass of H2) Step 2: convert Step 1 value to kJ/mol (multiply Step 1 value by 483.6 divided by 2 mol) Step 3: convert g of O2 to mol of O2 (divide mass of O2 by molar mass of O2) Step 4 convert Step 3 value to kJ/mol (multiply Step 3 value by 483.6 divided by 1 mol) Step 5: determine which is the LR to determine how much energy can be produced

When aqueous solutions of silver nitrate and potassium dichromate are mixed, an exchange reaction occurs, and silver dichromate is obtained as a red solid. The overall chemical equation for the reaction is as follows: 2 AgNO3(aq) + K2Cr2O7(aq) → Ag2Cr2O7(s) + 2 KNO3(aq) What mass of Ag2Cr2O7 is formed when 500 mL of 0.17 M K2Cr2O7 are mixed with 250 mL of 0.57 M AgNO3?

Step 1: convert the mL of each reactant to L Step 2: convert the L of each reactant to mol Step 3: multiply the Step 2 values by the mole(s) of the opposite substance in the equation divided by the mole(s) of the same substance in the equation Step 4: identify the LR Step 5: identify the calculated mol in step 2 that correlates to the LR Step 6: multiply that value by the molar mass of Ag2Cr2O7 divided by the moles used in the equation

The combustion of methane releases 891 kJ of heat. Describe the steps needed to determine how much heat is released by the combustion of 2.00 grams of CH4(g). CH4(g) + 2 O2(g) = CO2(g) + 2 H2O(g)

Step 1: convert to moles (2 g CH4 divided by molar mass of CH4) Step 2: multiply Step 1 value by 891 kJ/mol

2 moles of propane reacts with 8 moles of oxygen. Find the limiting reactant. C3H8 + 5O2 = 3CO2 + 4H2O

Step 1: find LR Step 1a: divide 2 moles of propane by 1 mol Step 1b: divide 8 moles by 5 mol Step 2: determine the LR by finding which value from Step 1a/b is smaller

The molecular weight of a gas is 173.6 g/mol. Determine its density at 25.0 degrees C and 1.00 atm pressure in grams per liter.

Step 1: find equation (d = MP / RT) Step 2: find constant (R = 0.08206) Step 3: convert C to K Step 4: input values and calculate

92 mL of sulfur dioxide gas is mixed in a sealed syringe (with a movable plunger) with 86 mL of oxygen gas to give a total of 178 mL of gas. 2SO2 + O2 = 2SO3 Determine the final volume of gas in the syringe after the reaction. (Assume pressure and temperature remain constant).

Step 1: find how many mL of SO3 are produced from mL of SO2 Step 1a: multiply 92 mL by 2 moles of SO3 divided by 2 moles of SO2 Step 2: find how many mL of O2 reacted with mL of O2 Step 2a: multiply 92 mL by 1 mole of O2 divided by 2 moles of SO2 Step 3: subtract the Step 2a value from 86 mL Step 4: add 92 mL to Step 3 value to find final volume

The value of ΔH° for the reaction below is -6535 kJ. Describe how you would determine the heat released (in kJ) for the combustion of 16.0 g of C6H6 (l). 2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(l)

Step 1: find molar mass of C6H6 Step 2: convert grams of C6H6 (16) to moles of C6H6 Step 3: multiply Step 2 value by -6535 kJ and divide by number of moles in reaction (2)

When 250 g copper metal at -20.0 ˚C is combined with liquid water at 0.0 ˚C. Determine the maximum mass of water that can be frozen by the copper. The heat capacity of copper is 0.385 J/g K, and the heat capacity of water is 4.184 J/g K. The Hfus of water is 333 J/g. The Hvap of water is 2570 J/g.

Step 1: let x = mass of water Step 2: set up equation (mcT = - mHfus) Step 3: input values and solve

A 25.00 mL sample of KOH is titrated with 28.68 mL if 0.2120 M HNO3(aq) to reach the equivalence point. Describe how you would find the concentration of the KOH solution.

Step 1: multiply V2 (28.68) by M2 (0.212) Step 2: divide Step 1 value by V1 (25.00)

What is the total internal translational (kinetic) energy of the Cl2 molecules in a 11.2 liter bulb at 0 degrees C and 8 atm? Describe the steps you would take to solve.

Step 1: multiply pressure (8) by the volume (11.2) Step 2: divide the Step 1 value by R (0.08206) Step 3: divide the Step 2 value by T in K (273) Step 4: multiply Step 3 value by 3/2

Given the data below, describe how to determine the heat of reaction (ΔrH°) for the following reaction. 3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g) NO2 (g) = 33.18 kJ/mol H2O (l) = -285.83 kJ/mol HNO3 (aq) = -207.36 kJ/mol NO (g) = 90.25 kJ/mol

Step 1: multiply the coefficients of each substance by their respective H values Step 2: find the sum of the values in Step 1

If 21.0 grams of ice at 0◦ C and 21.0 grams of liquid water at 100◦ C are placed in an insulated container. What will be the temperature of the water after it reaches equilibrium? CH2O(g) 1.996 J/g c CH2O(l) 4.184 J/g c CH2O(s) 2.108 J/g c ∆Hfus 333 J/g ∆Hvap 2570 J/g

Step 1: set up equation (q of melting ice + q of warming water from 0 degrees C + q of cooling water from 100 degrees C) Step 2: input values and solve for x ((m*Hfus) + (m*c*x-0) + (m*c*x-100)

In the "collapsing can" experiment demonstrated in class (where a small amount of water was added to an empty soda can and brought to a boil for several minutes) which of the following statements is false? a) Before heating, the pressure of gas inside the open can was the same as the pressure outside of the open can. b) When the water was boiling in the can, the pressure of gas inside the open can was the same as the pressure outside of the open can. c) When placed in the cold water, the water vapor in the can condensed to liquid water. d) The vacuum created in the can pulled the walls of the can inwards.

The vacuum created in the can pulled the walls of the can inwards.

Which of the following are true for an ideal gas? Select all that apply. a) The volume of the gas is negligible. b) All particles in a sample at 300 Kelvin are moving at identical speeds. c) The attraction between gas particles is negligible. d) The sample will be colorless.

The volume of the gas is negligible. The attraction between gas particles is negligible.

A sample of water is in a closed container with variable volume. It is heated to its boiling point and allowed to boil. The sample is then allowed to condense back into liquid water, and then it is cooled back to its initial temperature. T/F; Even if the process took place at constant pressure, work was done during any step in the process.

True

A sample of water is in a closed container with variable volume. It is heated to its boiling point and allowed to boil. The sample is then allowed to condense back into liquid water, and then it is cooled back to its initial temperature. T/F; H for the entire process, start to finish, is 0.

True

A sample of water is in a closed container with variable volume. It is heated to its boiling point and allowed to boil. The sample is then allowed to condense back into liquid water, and then it is cooled back to its initial temperature. T/F; Heat is exchanged with surroundings during the process.

True

A sample of water is in a closed container with variable volume. It is heated to its boiling point and allowed to boil. The sample is then allowed to condense back into liquid water, and then it is cooled back to its initial temperature. T/F; When the entire process is considered, the change in energy equals the change in enthalpy.

True

Which of the following is not a state function? a) Temperature b) Enthalpy c) Work d) Internal energy

Work

If the temperature is decreased, the average speed and kinetic energy of the gas molecules ___ (increase/decrease).

decrease

If a reaction is endothermic, the kinetic energy of the reaction would ___ (increase/decrease) and the chemical energy would ___ (increase/decrease).

decrease increase

If the gas volume is decreased, the distance to the container walls ___ (increases/decreases), and the frequency of collisions with the wall ___ (increases/decreases), thereby ___ (increasing/decreasing) the pressure.

decreases increases increasing

If the temperature of a gas is decreased, a constant pressure may be maintained only if the volume occupied by the gas ___ (increases/decreases). This will result in ___ (greater/lesser) average distances traveled by the molecules to reach the container walls.

decreases lesser

Describe how to find pressure.

divide force by area

Describe how to solve for the molarity (M).

divide the mol of the solute by the volume in L

Breaking bonds is always ___ (exo/endo)thermic, while forming bonds is always ___(exo/endo)thermic.

endo exo

If the kinetic energy of a reaction decreases and the chemical energy increases, this is an ___ (exo-/endo-) thermic reaction.

endothermic

Is breaking bonds endothermic or exothermic?

endothermic

Two reagents react in a sealed, insulated calorimeter such that no heat can flow into or out of the calorimeter. During the process of reaction, the water inside the calorimeter gets colder. Considering the system to be the reagents only (and not the water), and the surroundings to be everything else (including the water), this process is: a) exothermic b) endothermic c) q=0

endothermic

A chemical reaction that absorbs heat from the surroundings is said to be __________ and has a __________ ΔH at constant pressure.

endothermic (+)

If the kinetic energy of a reaction increases and the chemical energy decreases, this is an ___ (exo-/endo-) thermic reaction.

exothermic

Is forming bonds endothermic or exothermic?

exothermic

Two reagents react in a sealed, insulated calorimeter such that no heat can flow into or out of the calorimeter. During the process of reaction, the water inside the calorimeter gets warmer. Considering the system to be the reagents only (and not the water), and the surroundings to be everything else (including the water), this process is: a) exothermic b) endothermic c) q=0

exothermic

A chemical reaction that releases heat to the surroundings is said to be __________ and has a __________ ΔH at constant pressure.

exothermic (-)

Molecules with lower masses will have ___ (slower/higher speeds) than molecules with higher masses.

higher

If the temperature is increased, the average speed and kinetic energy of the gas molecules ___ (increase/decrease).

increase

If a reaction is exothermic, the kinetic energy of the reaction would ___ (increase/decrease) and the chemical energy would ___ (increase/decrease).

increase decrease

If the gas volume is increased, the distance to the container walls ___ (increases/decreases), and the frequency of collisions with the wall ___ (increases/decreases), thereby ___ (increasing/decreasing) the pressure.

increases decreases decreasing

If the temperature of a gas is increased, a constant pressure may be maintained only if the volume occupied by the gas ___ (increases/decreases). This will result in ___ (greater/lesser) average distances traveled by the molecules to reach the container walls.

increases greater

If the volume is held constant, the decreased speed of the gas molecules results in ___ (less/more) frequent collisions with the walls of the container, therefore ___ (decreasing/increasing) the pressure.

less decreasing

When a volume expands, work is ___ (less than/greater than) zero. What does this mean about energy?

less than energy is transferred out

If the volume is held constant, the increased speed of the gas molecules results in ___ (less/more) frequent collisions with the walls of the container, therefore ___ (decreasing/increasing) the pressure.

more increasing

Describe how to find force.

multiply pressure by area

Describe how to solve for mol of solute.

multiply the molarity by the volume in L

Gay-Lussac's law states that ___ and ___ are directly proportional. Avagadro's law states that the ___ of a substance is directly proportional to the ___. 1) temperature, volume, pressure, amount 2) pressure, temperature, amount, volume 3) pressure, amount, volume, temperature 4) amount, volume, temperature, pressure

pressure, temperature, amount, volume

For the following chemical reaction that takes place at constant pressure: 2Na(s) + 2H2O(l) = 2NaOH(aq) + H2(g) H = ‐365.7 kJ/mol Which of the following statements are true? (i) q = ‐365.7 kJ (ii) Work is done by the system on the surroundings. (iii) E = ‐365.7 kJ (iiii) Work is done by the surroundings on the system

q = ‐365.7 kJ Work is done by the system on the surroundings.

Two reagents react in a sealed, insulated calorimeter such that no heat can flow into or out of the calorimeter. During the process of reaction, the water inside the calorimeter gets colder. Consider the system to be the contents of the calorimeters (reagents and water), this process is: a) exothermic b) endothermic c) q=0

q=0

Does breaking bonds release or require energy?

release

Does forming bonds release or require energy?

require

Molecules with higher masses will have ___ (slower/higher speeds) than molecules with lower masses.

slower

If in a chemical change the reactants become stable products with a lower chemical potential energy, the electrostatic attractive forces between and within the atoms and molecules of the products are ____ (weaker/stronger) compared to those in the initial reactants.

stronger

On a graph, how would it be displayed if a gas's molecules were at slower speeds due to lower temperatures?

the distribution would shift left and peaks

Charles's law states that the ___ of a given amount of gas is directly proportional to its ___ on the kelvin scale when the pressure is held constant. 1) pressure, amount 2) amount, temperature 3) volume, temperature 4) amount, volume

volume, temperature

Assume your hand and the reactants all start at the same temperature. As each process occurs, think about whether your hand feels warmer or cooler as the process (or processes) occur. The oxidation of glucose to form carbon dioxide and water in a test tube that you are holding makes your hands feel ___ (warm/cold).

warm

Assume your hand and the reactants all start at the same temperature. As each process occurs, think about whether your hand feels warmer or cooler as the process (or processes) occur. The reaction of HCl with Mg(s) in a test tube that you are holding makes your hands feel ___ (cold/warm).

warm

If in a chemical change the reactants become stable products with a higher chemical potential energy, the electrostatic attractive forces between and within the atoms and molecules of the products are ____ (weaker/stronger) compared to those in the initial reactants.

weaker