The substances that are present before a chemical reaction takes place are called |
reactants |
Hydrochloric acid, HCl, is added to solid NaOH. After the reaction is complete, NaCl dissolved in water remains. What are the products of this chemical reaction? |
NaCl and H2O |
Which of the following does NOT state what the arrow means in a chemical equation? |
conserves |
Which of the following does NOT show the law of conservation of mass? |
24 mL of Mg burn in 32mL O2 to produce 56 mL of MgO. |
Which of the following is chemical equation that accurately represents what happens when sulfur and oxygen react to form sulfur trioxide? |
2S+3O–>2SO3 |
Which of the following is a balanced chemical equation for the synthesis of NaBr from Na and Br2? |
2Na+Br2–>2NaBr |
Methane, CH4, burns in oxygen gas to form water and carbon dioxide. What is the correct balanced chemical equation for this reaction? |
CH4+2O2–>2H2O+CO2 |
An industrial process makes calcium oxide by decomposing calcium carbonate. Which of the following is NOT needed to calculate the mass of calcium oxide that can be produced from 4.7kg of calcium carbonate? |
the volume of the unknown mass |
The coefficents in a balanced chemical equation always can express the ratio of |
moles of reactants and products |
When magnesium carbonate, MgCO2, reacts with nitric acid, HNO3, magnesium nitrate and carbonic acid form. Carbonic acid then breaks down into water and carbon dioxide. What two types of reactions take place in this process? |
double-replacement and decomposition |
Which of the following is NOT always true about a synthesis reaction? |
There is only one reactant. |
Which of the following takes place during a redox reaction? |
Electrons are both gained and lost. |
In a chemical reaction, an iron atom became the ion Fe2+. What happened to the iron atom? |
It lost electrons and was oxidized. |
In a compound, chemical energy is contained in the |
bonds |
Which of the following statements is true about what happens during a chemical reaction? |
Bonds of the reactants are broken, and bonds of the products are formed. |
In terms of energy, how would you classify the following chemical reaction? 2Cu+O2–>2CuO+315 kJ |
exothermic |
For the chemical reaction C2H6+137 kJ–>C2H4+H2, the chemical energy of the |
products is greater that the chemical energy of the reactant. |
The total amount of energy before and after a chemical reaction is the same. Thus, energy is |
conserved |
For the chemical reaction H2+CO2–> H2O+CO, the energy contained in the reactants is 352 kJ, and the energy contained in the products is 394 kJ, assuming 1 mol of each substance is present. Which of the following statements is true? |
42 kJ is absorbed, and the reaction is endothermic |
Reaction rates do NOT tell you how fast |
substances are changing state. |
In general, if the temperature of a chemical reaction is increased, reaction rate |
increases |
A log is burning in the fireplace. If the amount of oxygen reaching the log is decreased, which of the following statements is true? |
The reaction rate decreases |
When the forward and reverse paths of a change occur at the same rate, |
the system is in equilibrium |
The equation 2NO2<–>N2O4 shows a system |
in chemical equilibrium |
What happens to he reaction 2NO2<–>N2O4 +57.2 kJ when the temperature of the reaction is increased? |
More reactant is formed |
The reaction H2CO3+H2O<–> H3O1++HCO3- takes place in water. What happens to the equilbrium when the pressure is increased? |
It does not change |
The reaction in Figure 7-1 shows the formation of ammonia from nitrogen and hydrogen in the Haber process. |
Any effect will depend on the amount of change of temperature and concentration. |
Chapter 8 Science
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