Introduction to Chemistry; Atoms, Molecules and Ions; Mass Relationship
1.
The density of sulfuric acid in a certain car battery is 1.41 g/mL. Calculate the mass of 242 mL of the liquid.
2.
The temperature on the surface of the sun is about 6300°C. What is this temperature in degrees Fahrenheit?
3.
601K is the melting point of lead. What is the temperature in degrees Celsius?
4.
Convert the following numbers into scientific notation: a.
3,400 b.
0.000023 c.
101,000
5.
Convert the following numbers into standard notation: a.
2.30 x 10 4 b.
1.76 x 10 -3 c.
1.901 x 10 -7
6.
Express the answers to the following calculations in scientific notation: a.
0.0095 + (8.5 X 10 -3 ) b.
653 / (5.75 X 10 -8 )
7.
What are the numbers of significant figures in each of the following: a.
40.2 g/cm 3 b.
0.0000003 cm c.
0.7 min
8.
Carry out the following operations and show in your scripts. Express your answer in significant figures: a.
7.310 km / 5.70 km b.
(3.26 X 10 -3 mg) (7.88 X 10 -5 mg) c.
(4.02 X 10 6 dm) + (7.74 X 10 7 dm) d.
(7.8 m - 0.34 m) / (1.15 s + 0.82 s)
CHE101/HbR/SPR-16

9.
Zinc (Zn) is a silvery metal that is used in making brass (with copper) and in plating iron to prevent corrosion. How many moles of Zn are there in 45.9 g of
Zn?
10.
Sulfur (S) is a nonmetallic element that is present in coal. When coal is burned, sulfur is converted to sulfur dioxide and eventually to sulfuric acid, which gives rise to the acid rain phenomenon. How many atoms are in 25.1 g of S?
11.
Methane (CH
4
) is the principal component of natural gas. How many moles of
CH
4
are present in 4.83 g of CH
4
?
12.
How many hydrogen atoms are present in 43.8 g of urea [(NH
2
)
2
CO], which is used as a fertilizer, in animal feed, and in the manufacture of polymers? The molar mass of urea is 60.06 g
13.
Calculate the percent composition by mass of H, P, and O in Phosphoric acid (H
3
PO
4
).
14.
Ascorbic acid (vitamin C) cures scurvy. It is composed of 40.92 percent carbon
(C), 4.58 percent hydrogen (H), and 54.50 percent oxygen (O) by mass. Determine its empirical formula.
15.
A sample of a compound contains 1.52 g of nitrogen (N) and 3.47 g of oxygen
(O). The molar mass of this compound is between 90 g and 95 g. Determine the molecular formula and the accurate molar mass of the compound.
16.
A sample of a compound containing boron (B) and hydrogen (H) contains 6.444 g of B and 1.803 g of H. The molar mass of the compound is about 30 g. What is its molecular formula?
17.
Which of the following has a greater mass: 2 atoms of lead or 5.1 x 10 -23 mole of helium?
18.
The density of water is 1.00 g/mL at 4°C. How many water molecules are present in 2.56 mL of water at this temperature?
19.
The molar mass of caffeine is 194.19 g. Is the molecular formula of caffeine
C
4
H
5
N
2
O or C
8
H
10
N
4
O
2
?
20.
A general balanced equation for respiration is given below:
C
6
H
12
O
6
+ 6O
2
 6CO
2
+ 6H
2
O
If 856 g of C
6
H
12
O
6 is consumed by a person over a certain period, what is the mass of CO
2
produced by respiration?
CHE101/HbR/SPR-16