My exam #3

A chemist wishes to perform the following reaction: N2+3H2->2NH3 If only 14.0 g of N2 is available, what is the minimum amount, in grams, of H2 needed to completely react with this quantity of N2? A) 6.06 g B) 1.51 g C) 3.03 g D) 1.01 g E) none

C) 3.03 g

The theoretical yield of a reaction is 75.0 grams of product and the actual yield is 42.0g. What is the percent yield? A) 75.0 B) 31.5 C) 56.0 D) 178 E) none

C) 56.0

Consider the following equation: CO+2H2->CH3OH deltaH rxn=-128 kJ Calculate the amount of heat (in kJ) associated with complete reaction of 8.08 g H2. A) -256 kJ B) -512 kJ C) -1024 kJ D) -1034 kJ E) none

A) -256 kJ

How many moles of water are made from complete reaction of 2.2 moles of oxygen gas with hydrogen gas? Given the reaction: 2H2+O2->2H2O A) 4.4 B) 1.1 C) 3.3 D) 2.2 E) none

A) 4.4

When the equation, _O2+_C5H12->_CO2+_H2O is balanced, the coefficient of O2 is A) 8 B) 5 C) 3 D) 4 E) none

A) 8

What is the limiting reactant for the reaction below given that you start with 2.50 grams C and 2.50 SiO2? Reaction: C+ SiO2 -> SiC + O2 A) SiO2 B) SiC C) C D) O2 E) none

A) SiO2

Tricycle factory uses this to produce one tricycle: 3 tires, 1 frame, 2 pedals. If the factory has 270 tires, 90 frames, and 170 pedals, which item limits the amount of tricycles that can be assembled A) pedals B) frames C) tires D) both tires and frams are limiting E) none

A) pedals

What is the mass of 1.56 x 10^21 atoms of magnesium in grams? A) 0.142 B) 0.0630 C) 1.07 x 10^-4 D) 4.72 x 10^-5 E) none

B) 0.0630

Bauxite is an ore that contains the element aluminum. If you obtained 108 grams of aluminum from an ore sample that initially weighed 204 grams, what is the mass percent of aluminum in this bauxite ore? A) 0.53 B) 52.9 C) 15.6 D) 47.1 E) none

B) 52.9

Which of the following compounds is INSOLUBLE? A) magnesium sulfate B) magnesium phosphate C) magnesium iodide D) magnesium nitrate E) none

B) magnesium phosphate

How many moles of Cu are in 1.48 x 10^25 Cu atoms? A) 0.0408 B) 1.54 x 10^25 C) 24.6 D) 6.022 x 10^23 E) none

C) 24.6

An iron chloride compound contains 55.85 g of iron and 106.5 of chlorine. What is the most likely empirical formula for this compound? A) FeCl2 B) Fe2Cl C) FeCl3 D) Fe3Cl E) FeCl

C) FeCl3

The compound sodium sulfate is soluble in water. When the compound dissolves in water, which ion listed below would be present in solution? A) O2- B) Na2^2+ C) SO4^2- D) S2- E) none

C) SO4^2-

In comparing a balloon containing 25 g of helium to a balloon containing 25 g of neon, which one of the following statements is TRUE? A) Each balloon has an equal number of atoms B) This scenario can't happen because gas has no mass C) The helium balloon has more atoms D) The neon balloon has more atoms E) none

C) The helium balloon has more atoms

What type of a reaction occurs when a silver nitrate solution is mixed with sodium chloride solution? A) oxidation-reduction B) gas evolution C) precipitation D) acid-base neutralization E) none

C) precipitation

Considering the following precipitation reaction: Pb(NO3)2(aq)+2KI(aq)->PbI2(s)+2KNO3(aq) What is the correct ionic equation? A) Pb2++(NO3)2-+2K++2I-->PbI2(s)+2K++2NO3- B) Pb2++2NO3-+2K++2I-->Pb2++2I-+2K++2NO3- C) Pb2++2NO3-+2K++2I-->PbI2(s)+2K++NO3- D) Pb2+2NO3-+2K++2I-->PbI2(s)+2K++2NO3- E) none

D)

What are the coefficients for the following reaction when it is properly balanced? _Na3PO4+_3Ba(NO3)2->_6NaNO3+_Ba3(PO4)2 A) 2,1,1,3 B) 6,1,3,2 C) 2,3,1,6 D) 2,3,6,1 E) none

D) 2,3,6,1

One mole of potassium sulfate contains: A) 1 mole of potassium B) 2 moles of sulfur C) 3 moles of potassium D) 4 moles of oxygen E) none

D) 4 moles of oxygen

Identify the oxidation-reduction reactions among the following: 1. Zn(s)+Cu2+(aq)->Zn2+(aq)+Cu(s) 2. 2Na(s)+Cl2(aq)->2NaCl(s) 3. 2Mg(s)+O2(g)->2MgO A) 1 and 2 only B) 2 and 3 only C) 1 and 3 only D) All of 1,2, and 3 E) none

D) All of 1,2, and 3

Which of the following would NOT be a product from mixing hydrochloric acid with a solution of sodium sulfite? A) SO2 (g) B) H2O (I) C) NaCl (aq) D) H2 (g) E) none

D) H2 (g)

What is the molecular formula of a compound given the molar mass of the compound is 30.04 gram and the empirical formula is NH? A) NH B) N2H6 C) N4H4 D) N2H2 E) none

D) N2H2