chem part 4

What is the enthalpy for a two-step reaction, given for the two steps are +206 kJ and -136 kJ, respectively?

+70kj

Suppose that a chemical equation can be written as the sum of two other chemical equations. If two reactions have values of -658 kJ and +458 kJ, what is for the reaction that is their sum?

-200Kj

A 5.0 g sample of silver is heated from 0°C to 35°C and absorbs 42 J of energy as heat. What is the specific heat of silver?

0.24J/(g)(c)

For the reaction represented by the equation SO3 + H2O ® H2SO4, how many grams of sulfuric acid can be produced from 200. g of sulfur trioxide and 100. g of water?

245g

How much energy is absorbed as heat by 20. g of gold when it is heated from 25°C to 35°C? The specific heat of gold is 0.13 J/g·°C.

26J

If a piece of aluminum is heated from 40.0C to 70.0C, what is the value of ?

30.0K

For the reaction represented by the equation 2KlO3 ® 2KCl + 3O2, how many moles of potassium chlorate are required to produce 250. g of oxygen?

5.21 mol

For the reaction represented by the equation 2Fe + O2 ® 2FeO, how many grams of iron(II) oxide are produced from 8.00 mol of iron in an excess of oxygen?

575 g

For the reaction represented by the equation CH4 + 2O2 ® CO2 + 2H2O, how many moles of carbon dioxide are produced from the combustion of 100. g of methane?

6.23 mol

For the reaction represented by the equation 2Na + Cl2 ® 2NaCl, how many grams of sodium chloride can be produced from 500. g each of sodium and chlorine?

824 g

For the reaction represented by the equation Mg + 2HCl ® H2 + MgCl2, calculate the percentage yield of magnesium chloride if 100. g of magnesium react with excess hydrochloric acid to yield 330. g of magnesium chloride.

84.2 percent

DH =

Hproducts - Hreactants

What is the measured amount of a product obtained from a chemical reaction?

actual yield

The Greek letter D stands for

change in

Spontaneous reactions are driven by

decreasing enthalpy and increasing entropy

Which of the following is a measure of the randomness in a system?

entropy

The majority of spontaneous chemical reactions in nature are

exothermic

is always negative for a

exothermic reaction

As ice melts, the water molecules

go from a well-ordered phase to a less-ordered phase

Which of the following is transferred due to a temperature difference?

heat

What units are used to measure energy as heat?

joules or kilojoules

In an endothermic reaction, the total energy at the beginning of the reaction is

less than the total energy at the end of the reaction

For an endothermin reaction, is always

positive

When the limiting reactant in a chemical reaction is completely used, the

reaction stops

What is the energy required to raise the temperature of 1 g of a substance by 1°C or 1 K?

specific heat

Which of the following is a measure of the average kinetic energy of the particles in a sample of matter?

temperature

A piece of metal is heated, then submerged in cool water. Which statement below describes what happens?

the temperature of the water will increase and the temperature of the metal will decrease

What is the maximum possible amount of product obtained in a chemical reaction?

theoretical yield

In a calorimeter, the energy content of a substance is calculated from measurement of the temperature change in a known mass of

water