Gen. Chem.- Chap. 3
Choose the correct answer for each question.
 

1Which of the following statements is NOT true?
The molar mass of an element is numerically equal to its atomic weight in the periodic table.
1 mol of S and 32.00 g of S both contain the same no. of atoms, 6.022 x 1023
The atomic weight in the periodic table is actually a weighted average of all the isotopes of that element.
The relative masses of the elements in the periodic table are based on the mass of H.

2The number of atoms in 0.800 g of Ag is... (A.M. Ag = 107.9)
4.46 x 1021 atoms
5.20 x 1025 atoms
86 atoms
1.43 x 10-22 atoms

3The molar mass of potassium sulfate is...
87.1 g/mol
135.1 g/mol
174.2 g/mol
231.1 g/mol

4How many grams of Pb(NO3)2 are in 0.250 mol of Pb(NO3)2?
51.8 g
82.8 g
117.9 g
331.2 g

5The mass % C in benzaldehyde- C7H6O is...
11.3%
50%
63.4%
79.2%

6A compound contains 2.15% H, 29.80% N, and 68.06% O by mass. The simplest formula of the compound is...
HNO
HNO2
HNO3
HN15O34

7When the following equation is balanced,
__C6H12O6 + O2 -----> __CO2 + __H2O
the coefficent in front of the C6H12O6 is...
1
2
4
6

8Given the following balanced equation...
2 Fe2O3 + 3 C -----> 4 Fe + 3 CO2
How many grams of Fe can be produced from 100. grams of Fe2O3?
17.5 g Fe
35.0 g Fe
69.9 g Fe
81.2 g Fe

9Suppose the above reaction was carried out and the amount of Fe obtained was 15.0 g Fe. The % yield for this synthesis was...
4.66%
15.0%
21.4 %
79.2%

10Given the following balanced equation,
2 Fe2O3 + 3 C -----> 4 Fe + 3 CO2
How many grams of Fe can be produced starting with 100 g of Fe2O3 and 25.0 g of C?
69.9 g
125 g
155 g
225 g