An empty graduated cylinder weighs 55.29 g when filled with 48.1 mL of an unknown liquid it weighs 92.39 g density ofthe unknown liquid is
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30A: Solutions to Final Exam Review
1. Express the following numerical values in standard scientific notation:
(a) 0.005082 (b) 168000 (c) 453.6 x 103
Answer: (a) 5.082 x 10-3 (b) 1.68 x 105 (c) 4.536 x 105
2. Round off the following numerical values to THREE significant figures. (It might be necessary to use scientific notation to express the correct significant figures.)
(a) 219985 (b) 0.027765 (c) 299.785
Answer: (a) 2.20 x 105 (b) 2.78 x 10-2 (c) 3.00 x 102
3. Perform the following unit conversions:
(a) 75.0 miles ( kilometers; 75.0 mi x = 121 km
(b) 2140 pounds ( kilograms; 2140 lb x = 971 kg
(c) 375 oF ( oC and ( Kelvin; (375 32)oF x = 191oC; 191 + 273 = 464 K
(d) 600. K ( oC ( oF. 600 K 273 = 327oC; (327oC x ) + 32oC = 621oF
4. An empty graduated cylinder weighs 55.26 g. When filled with 50.0 mL of an unknown liquid, it weighs 92.39 g. Calculate the density of the unknown liquid. (Ans: 0.743 g/mL)
Volume of liquid = 50.0 mL; mass of liquid = 92.39 g 55.26 g = 37.13 g
Density = = = 0.743 g/mL
5. If the density of alcohol is 0.785 g/mL, what is the weight (in grams) of a 58.6-mL sample of alcohol? (Answer: 46.0 g)
Mass (weight) = Volume x density = 58.6 g x (0.785 g/mL) = 46.0 g
6. Indicate whether each of the following implies a physical or a chemical property?
(a) Water is liquid at room temperature and 1 atm; Physical property
(b) Ether is very volatile; Physical property
(c) Gasoline is a very flammable liquid; Chemical property
(d) Sugar is soluble in water; Physical property
(e) Aluminum powder is highly combustible; Chemical property
7. Indicate whether each of the following describes a physical or chemical process.