Review for Exam over Unit 1
Chemistry PreAP
1) The narrowness of range of measurements is known as _______________________.
2) The closeness to a true value is known as ___________________________.
3) State the number of significant figures in each of the following:
3.80 L 0.0042 km 806.0 cm
7500 mL 2.026 x 105 nm
4) Round off the quantity 1.2960546 to two, three, four, five, six, and seven significant figures.
Two Three Four
Five Six Seven
For 3 and 4, assume that all numbers are correct with respect to significant figures. Calculate the answers and round them off to the proper number of significant figures.
5) (3.70 x 10-6)(2791) = 6) 106.054
(639.92) (0.0082) 35.60
0.01428
+ 2.3311
7) A grain of sand weighs 0.8 milligrams. Express this in (a) grams and (b) kilograms.
8) A fisherman caught a 1.26~kilogram trout. How many pounds is this?
(453.6 grams = 1 pound)
9) How many (a) centimeters and (b) millimeters are in 79.8 meters?
10) What number of meters is equal to 60.5 kilometers?
11) How many feet are in 4.92 meters? (2.54 cm = 1 inch)
12) Calculate the number of liters in 94.1 gallons. (3.785 L = 1 gal)
13) How many cubic meters are in 18.2 cubic yards? (1 meter = 39.37 in.)
14) Find the number of liters in 786 cubic centimeters.
15) Express in exponential notation the numbers given in conventional decimal form; express in conventional decimal form the numbers given in exponential notation.
a) 7,835,000 b) 0.0000218 c) 3.19 x 10-4 d)5.03 x 105
(2.89x105)(5)(3.08x10-6)(1.09x10-4)
e) Calculate the following: (7.21 x 103)(5.82 x 10-6)(3)
16) How many seconds does it take a race horse to run six furlongs at 40.7
miles per hour if: I furlong = 40 rods; 5.5 yards = 1 rod; and 5280 feet =1 mile?
17) A sample of a chemical compound is analyzed and found to contain 2.31 grams of sodium, 1.40 grams of nitrogen, and 4.80 grams of oxygen. Calculate the percentage of sodium in the compound.
18) How would the ratio 24 g / mole be expressed in kilograms per kilomole?
19) The newspaper account of a local election states that the 18,421 votes cast represented 67.8% of the registered voters. How many registered voters are in that district?
20) The registrar of a college reported that this year’s enrollment is only
91.2% of last year’s total of 7419. What is this year’s enrollment?