Reaction Pathways — Unit test Answers

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Consider the reaction pathway graph below. Which method would provide evidence to support the inference that this is an exothermic reaction?

add A and C

add E and D

subtract A from C

subtract E from D

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Consider the chemical equation for the combustion of sugar._C6H12O6(s) + _O2(g) _CO2(g) + _H2O(l)Which sequence of coefficients should be placed in the blanks to balance this equation?

1, 6, 6, 6

6, 1, 6, 1

3, 3, 3, 6

1, 3, 3, 6

Which type of reaction has the general formula of AB + CD → AD + CB?

synthesis

decomposition

oxidation

replacement

Consider the chemical equation. 2NBr3 + 3NaOH N2 + 3NaBr + 3HOBrIf there are 40 mol of NBr3 and 48 mol of NaOH, what is the excess reactant?

NBr3

NaOH

HOBr

What is the percent by mass of oxygen in carbon dioxide (CO2)?Use .

27.29%

57.12%

72.71%

79.99%

What is the percent by mass of potassium in K3Fe(CN)6?Use .

16.96%

21.88%

25.53%

35.62%

What is the word equation for atoms of magnesium reacting with molecules of oxygen to produce magnesium oxide?

magnesium + magnesium oxide oxygen

magnesium + oxygen magnesium oxide

magnesium oxide + oxygen magnesium

magnesium + oxygen magnesium + oxygen

Consider the chemical equation.2H2 + O2 2H2OWhat is the percent yield of H2O if 87.0 g of H2O is produced by combining 95.0 g of O2 and 11.0 g of H2?Use .

56.5%

59.0%

88.5%

99.7%

Consider the reaction pathway graph below.Which letter represents the activated complex?

Which clue can be used to identify a chemical reaction as a decomposition reaction?

The reaction involves oxygen.

The reaction involves ions.

The reaction has a single reactant.

The reaction has a single product.

Which energy graph represents the nonspontaneous transition of graphite into diamond?

A graph with Reaction progression on the horizontal axis and energy on the vertical axis. A line starts low on the vertical axis, runs briefly parallel to the horizontal axis, slopes up sharply, curves down a short distance, and levels out.

A graph with Reaction progression on the horizontal axis and energy on the vertical axis. A line starts midway up the vertical axis, runs briefly parallel to the horizontal axis, slopes up sharply, curves down sharply, and levels out below the initial starting point.

A graph with Reaction progression on the horizontal axis and energy on the vertical axis. A line starts midway up the vertical axis, runs briefly parallel to the horizontal axis, slopes up a small amount, then curves down to level out below the initial starting point.

A graph with Reaction progression on the horizontal axis and energy on the vertical axis. A line starts midway up the vertical axis, runs briefly parallel to the horizontal axis, slopes up a moderate amount, then curves down sharply to level out below the initial starting point.

A reaction occurs when solid X is placed into solution Y. As a result, the temperature of the new solution increases by 3°C. The temperature rises another 2°C when more of solid X is added to the solution. What does this indicate about the effect of adding more solid?

It increased the number of molecular collisions.

It decreased the number of molecular collisions.

It decreased the space between the molecules and lowered the reaction rate.

It increased the space between the molecules and increased the reaction rate.

Which statement correctly describes the actual yield and the theoretical yield of a reaction?

The actual yield is calculated from the reactant amounts, but the theoretical yield must be measured for each instance of a reaction.

The actual yield is calculated from the amount of the limiting reactant, and the theoretical yield is calculated from the amount of the excess reactant.

The actual yield depends on the reaction conditions, but the theoretical yield varies only with reactant amounts.

The actual yield represents the maximum yield possible, and the theoretical yield assumes perfect reaction conditions.

Which statement best applies collision theory to preventing a dangerous reaction from occurring?

Store the reactants together at a low pressure.

Keep all sparks or flames away from the reactants.

Store the reactants together at a low temperature.

Keep the reactants in separate containers.

What happens as the activation energy increases?

The pressure of the system decreases.

The kinetic energy of colliding molecules changes.

The reactant surface area decreases.

The reaction begins to slow down.

Which statement best describes the reaction pathway graph for an exothermic reaction but not an endothermic reaction?

It has a hill in the middle that is the highest point.

It has a valley in the middle that is its lowest point.

The reactants are higher in energy than the products.

The products are higher in energy than the reactants.

This formula equation is unbalanced.Pb(NO3)2(aq) + Li2SO4(aq) PbSO4(s) + LiNO3(aq) Which coefficient should appear in front of LiNO3 in the balanced equation?

The equation shows the reaction between zinc metal and hydrochloric acid.Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)What is the theoretical yield of hydrogen gas if 5.00 mol of zinc are added to an excess of hydrochloric acid?