Chem 100, Pre-Lecture Ch.8

The enthalpy for the formation of 1 mole of NH3(aq) is -80.29 kJ/mol. What is the enthapy for the formation of 3 moles of NH3(aq)?

-240.87 kJ

Consider the reaction: 2 Al(s) + 3 Cl2(g) → 2 AlCl3(s) A chemist reacts 0.50 mol of aluminum with 0.80 mol of chlorine. If the limiting reactant is determined to be aluminum, what is the theoretical yield of aluminum chloride in moles?

0.50 mol AlCl3

What is the maximum mass, in grams, of NH3 that can be produced by the reaction of 1.0 g of N2 and 1.0 g of H2 using the reaction below? N2+H2→NH3 (not balanced)

1.2 g

Find the number of moles of water that can be formed if you have 166 mol of hydrogen gas and 78 mol of oxygen gas. Express your answer with the appropriate units.

156 mol

ow many grams of sodium oxide can be synthesized from 17.4 g of sodium? Assume that more than enough oxygen is present. The balanced equation is: 4Na(s) + O2(g) → 2Na2O(s) Express your answer in grams to one decimal place.

23.5 g Na2O

Suppose you have 48 bread slices and 38 cheese slices. How many cheese sandwiches can you make? Express your answer as an integer.

24 sandwiches

What maximum amount of ammonia in kilograms can be synthesized from 5.22 kg of H2 and 31.5 kg of N2? Express your answer in kilograms to one decimal place.

29.4 kg NH3

How many conversion factors (relationships) are given in the following chemical equation? 3 H2(g) + N2(g) → 2 NH3(g)

3 conversion factors

Ammonia can also be synthesized by this reaction: 3H2(g) + N2(g) → 2NH3(g) What maximum amount of ammonia in grams can be synthesized from 25.2 g of N2 and 8.42 g of H2? Express your answer in grams to one decimal place

30.7 g NH3

How many conversion factors (relationships) are given in the following chemical equation? 2 NO(g) + 5 H2(g) → 2 NH3(g) + 2 H2O(g)

6 conversion factors

How many conversion factors (relationships) are given in the following recipe? 1 cup flour + 2 eggs + ½ tsp baking powder → 5 pancakes

6 conversion factors

Magnesium hydroxide, the active ingredient in milk of magnesia, neutralizes stomach acid, primarily HCl, according to the reaction: Mg(OH)2(aq) + 2 HCl(aq) → H2O(l) + MgCl2(aq) How much HCl in grams can be neutralized by 5.50 g of Mg(OH)2 ? Express your answer in grams to two decimal places.

6.88 g HCl

Consider this combination reaction: 2Mg(s)+O2(g)→2MgO(s) ΔH=−1204 kJ What is the enthalpy for the decomposition of 1 mole of MgO(s) into Mg(s) and O2(g)?

602 kJ/mol

Pentacarbonyliron(0) (Fe(CO)5) reacts with phosphorous trifluoride (PF3) and hydrogen, releasing carbon monoxide: Fe(CO)5+2PF3+H2→Fe(CO)2(PF3)2(H)2+3CO If 6.0 g of Fe(CO)5 reacts with 4.0 g of PF3 and 4.0 g of H2, which is the limiting reagent?

PF3

When HCl(aq) and NaOH(aq) are mixed in a beaker, the beaker feels warm to the touch. What is known about the enthalpy of this reaction?

The reaction is exothermic.

Consider the photosynthesis reaction: 6 CO2(g) + 6 H2O(l) → 6 O2(g) + C6H12O6(aq) Which of following solution maps is used to find how many grams of glucose (C6H12O6) can be synthesized from 58.5 g of carbon dioxide (CO2)? Assume that there is enough water present to react with all of the carbon dioxide.

g CO2 → mol CO2 → mol C6H12O6 → g C6H12O6

For the reaction shown, calculate how many grams of oxygen form when each quantity of reactant completely reacts. 2 KClO3(s) → 2 KCl(s) + 3 O2(g) 2.72 g KClO3 0.361 g KClO3 83.6 kg KClO3 22.5 mg KClO3 Express your answers, separated by commas, in grams to three significant figures.

grams of oxygen = 1.06,0.141,32700,8.777⋅10−3 g O2

Which of the following is an example of a fossil fuel?

octane

Consider the following reaction: 2 NO(g) + 5 H2(g) → 2 NH3(g) + 2 H2O(g) Which set of solution maps would be needed to calculate the maximum amount of ammonia (NH3), in grams, that can be synthesized from 45.8 g of nitrogen monoxide (NO) and 12.4 g of hydrogen (H2)? I. g NO → mol NO → mol NH3 → g NH3 II. g H2 → mol H2 → mol NH3 → g NH3 III. g NO → mol NO → mol H2O → g H2O IV. g H2 → mol H2 → mol H2O → g H2O

solutions maps I and II