What is the correct value for Avogadro's number?

Question 1 of 12    4.0/ 4.0 Points
What is the correct value for Avogadro's number?

A. 6.022 × 102.3   

B. 6.022 × 1033   

C. 6.023 × 1022   
   

D. 6.022 × 1023   

E. none of the above   


Answer Key: D
Question 2 of 12    4.0/ 4.0 Points
What is the mass of 1.56 × 1021 atoms of magnesium in grams?

A. 4.72 × 10-5   
   

B. 0.0630   

C. 1.07 × 10-4   

D. 0.142   

E. none of the above   


Answer Key: B
Question 3 of 12    4.0/ 4.0 Points
Calculate the molar mass of ammonium carbonate.

A. 88.05 g/mol   
   

B. 96.09 g/mol   

C. 78.05 g/mol   

D. 112.09 g/mol   

E. none of the above   


Answer Key: B
Question 4 of 12    0.0/ 4.0 Points
What are the coefficients for the following reaction when it is properly balanced?___HCl + ___Mg ? ___MgCl2 + ___ H2

A. 2, 1, 2, 2   

B. 2, 1, 1, 1   

C. 1, 2, 1/2, 1   

D. 1, 1, 1, 2   
   

E. none of the above   


Answer Key: A
Question 5 of 12    4.0/ 4.0 Points
What type of reaction is the generic equation A + BC ? AC + B?

A. synthesis/combination   

B. double-displacement   

C. decomposition   
   

D. single displacement   

E. none of the above   


Answer Key: D
Question 6 of 12    4.0/ 4.0 Points
A precipitate is expected to be formed when an aqueous solution of sodium sulfate is added to an aqueous solution of

A. iron(III) chloride.   

B. magnesium chloride.   
   

C. barium chloride.   

D. potassium chloride.   

E. none of the above   


Answer Key: C
Question 7 of 12    4.0/ 4.0 Points
How many moles of sodium metal are needed to make 3.6 moles of sodium chloride? Given the reaction: 2Na + Cl2 ? 2NaCl
   

A. 3.6   

B. 7.2   

C. 1.8   

D. 0.9   

E. not enough information   


Answer Key: A
Question 8 of 12    4.0/ 4.0 Points
What is the limiting reactant for the reaction below given that you start with 10.0 grams of Al and 19.0 grams of O2? Reaction: 4Al + 3O2 ? 2Al2O3
   

A. Al   

B. Al2O3   

C. O2   

D. both Al and O2   

E. not enough information   


Answer Key: A
Question 9 of 12    4.0/ 4.0 Points
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. 178   
   

C. 56.0   

D. 31.5   

E. none of the above   


Answer Key: C
Question 10 of 12    0.0/ 4.0 Points
A chemist wishes to perform the following reaction: N2 + 3 H2 ? 2 NH3 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. 3.03 g   

B. 1.01 g   
   

C. 1.51 g   

D. 6.06 g   

E. none of the above   


Answer Key: A
Question 11 of 12    0.0/ 5.0 Points
An iron chloride compound contains 55.85 grams of iron and 106.5 grams of chlorine. What is the most likely empirical formula for this compound?

Fe3Cl

Model Short Answer: 


Comment: FeCl3
Question 12 of 12    5.0/ 5.0 Points
Write a balanced chemical equation for the following: A) Solid magnesium reacts with aqueous copper (I) nitrate to form aqueous magnesium nitrate and solid copper. B)Liquid methanol (CH3OH) reacts with oxygen gas to form gaseous carbon dioxide and gaseous water.

A) Mg (s) + 2 CuNO3 (aq) -> Mg(NO3)2 (aq) + 2 Cu (s) B) 2CH3OH (l) +3 O2 (g) -> 2CO2 (g) + 4 H2O (g)

Model Short Answer:  A) Mg(s) + 2CuNO3(aq) ? Mg(NO3)2(aq) + 2Cu(s)

B) 2 CH3OH (l) + 3 O2(g) ? 2 CO2(g) + 4 H2O(g)