What happens during an exothermic reaction? a. Energy is lost. b. Energy is created. c. Energy is released. d. Energy is absorbed.

Which of these represents the largest scale? a. a rift that has been spreading for millions of years, b. subsidence, c. compression, d. tension.

People are living longer, and families have fewer members. How will the combination of these two factors affect future transfer payments such as Social Security?

$$600\div10$$

What do population geographers use to study population patterns and trends?

The following reaction is exothermic. Which change will shift the equilibrium to the left?

$$\ce{2SO2(g) + O2(g) \rightleftharpoons 2 SO3(g)}$$

a) raising temperature

b) adding $\ce{SO3}$

c) removing $\ce{O2}$

d) all of the above

Sulphur trioxide, $\ce{SO3}$, is made by oxidation of $\ce{SO2}$, i.e.,

$$\ce{2SO2(g) + O2(g) -> 2SO3(g)}$$

If a 16 g sample of $\ce{SO2}$ gives 16 g of $\ce{SO3}$, the percentage yield of $\ce{SO3}$ is:

A) 60%

B) 75%

C) 80%

D) 100%

E) 125%;

Elemental $\ce{S}$ reacts with $\ce{O2}$ to form $\ce{SO3}$ according to the following reaction:

$$\ce{2S + 3O2 -> 2SO3}$$

(a) How many $\ce{O2}$ molecules are needed to react with 6.18 g of $\ce{S}$?

(b) What is the theoretical yield of $\ce{SO3}$ produced by the quantities described in Part (a)?

Explain what it means when a system in chemical equilibrium shifts to favor the products.

What is the concentration of OH$^-$ ions in a 0.0001 M solution of HCl?

Consider the following equilibrium system involving SO2, Cl2, and SO2Cl2 (sulfuryl dichloride): SO2 (g) + Cl2 (g) <=> SO2Cl2 (g) Predict how the equilibrium position would change if (a) Cl2 gas were added to the system; (b) SO2Cl2 were removed from the system; (c) SO2 were removed from the system. The temperature remains constant

When wood is burned, energy is released in the form of heat and light. Describe the reaction, and explain why this reaction does not violate the law of conservation of energy. Use the terms combustion, exothermic, and chemical energy.

All organic compounds a. come only from living organisms. b. contain only carbon and hydrogen. c. are biochemical compounds. d. have atoms connected by covalent bonds.

How many moles of the excess reactant remain at the end of the reaction?