Unit 4 Review

Write each of the following in scientific notation with two significant figures: a. 5000 L b. 30 000 g c. 100 000 m d. 0.000 25 cm

a. 5.0 * 103 L b. 3.0 * 104 g c. 1.0 * 105 m d. 2.5 * 10-4 cm

Perform each of the following calculations, and give an answer with the correct number of decimal places: a. 45.48 cm + 8.057 cm b. 23.45 g + 104.1 g + 0.025 g c. 145.675 mL - 24.2 mL d. 1.08 L - 0.585 L

a. 53.54 cm b. 127.6 g c. 121.5 mL d. 0.50 L

Calculate the number of moles in 25.0 g of each of the following: a. He b. O2 c. Al1OH23 d. Ga2S3 e. C4H10, butane

a. 6.25 mol of He b. 0.781 mol of O2 c. 0.321 mol of Al1OH23 d. 0.106 mol of Ga2S3 e. 0.430 mol of C4H10

Calculate each of the following: a. number of Ag atoms in 0.200 mol of Ag b. number of C3H8O molecules in 0.750 mol of C3H8O c. number of Cr atoms in 1.25 mol of Cr

0.432 mol of H2O

What is the total mass, in grams, of a dessert containing 137.25 g of vanilla ice cream, 84 g of fudge sauce, and 43.7 g of nuts?

265 g

Round off each of the following measurements to three significant figures: a. 1.854 kg b. 88.0238 L c. 0.004 738 265 cm d. 8807 m e. 1.8329 * 103 s

a. 1.85 kg b. 88.0 L c. 0.004 74 cm d. 8810 m e. 1.83 * 103 s

Identify the measurement in each of the following pairs that contains more significant figures: a. 11.0 m and 11.00 m b. 405 K and 405.0 K c. 0.0120 s and 12 000 s d. 2500 mL and 2.50 * 10-2 mL

a. 11.00 m b. 405.0 K c. 0.0120 s d. 2.50 * 10-2 mL

Calculate the mass, in grams, in 0.150 mol of each of the following: a. Ne

a. 3.03 g

Calculate the molar mass for each of the following: a. Cl2 b. C3H6O3 c. Mg3 1PO422

a. 70.90 g b. 90.08 g c. 262.9 g

Using the models of the molecules 1black = C, white = H, yellow = S, green = Cl2, determine each of the following for models of compounds 1 and 2: a. molecular formula c. molar mass (models in basic chemistry chapter 7-1 page 27).

a. S2Cl2 c. 135.04 g

Indicate the significant zeros, if any, in each of the following and give a reason: a. 0.0038 m b. 5.04 cm c. 800. L d. 3.0 * 10-3 kg e. 85 000 g

a. Zeros preceding the first nonzero digit are not significant. b. Zeros between nonzero digits are significant. c. Zeros after the first nonzero digit in a decimal number are significant. d. Zeros in the coefficient of a number in scientific notation are significant. e. Zeros in a large number without a decimal point are not significant

Indicate if each of the following is an exact number or a measured number: a. number of legs b. height of table c. number of chairs at the table d. area of tabletop

a. exact b. measured c. exact d. measured

How many significant figures are in each of the following? a. 11.005 kg b. 0.000 32 m3 c. 36 000 000 m d. 1.80 * 104 g e. 0.8250 L f. 30.0 °C

a. five SFs b. two SFs c. two SFs d. three SFs e. four SFs f. three SFs

Calculate the mass percent composition for each of the following compounds: c. C6H12O6

c. 40.00% C; 6.72% H; 53.29% O