Chapter 01 Conversion factors and Algebra Worksheet (KEY)

Transcription

1 Chapter 01 Conversion factors and Algebra Worksheet (KEY) 1. Perform the following calculations. a g (3.675 cm g cm 3) (9.223 g cm g = cm 3) a. b. b ml (19.30 g ml g ml ) g ( ml g) (19.30 g ml g ml ) = 2. While you are watching the news, you find out that an inch of rain fell in one single day on the city of San Francisco. Since you are as curious as your Chemistry Professor (yours truly!), you want to find out how much water this means. You look up on the internet for the approximate area of San Francisco and find out that the city has an area of square miles. How many gallons and how many liters of water fell that single day? (1 mi = 5280 ft ; 1 gal = 231 in 3 ; 1 gal = L) V(gal) = V(L) =

2 3. A cattle train left Miami and traveled toward New York. 14 hours later a diesel train left traveling at 45 km hr in an effort to catch up to the cattle train. After traveling for four hours the diesel train finally caught up. What was the cattle train s average speed? speed ( km hr ) = 4. Gold can be hammered into extremely thin sheets called gold leaf. An architect wants to cover a 100 ft 82 ft ceiling with gold leaf that is five-millionths of an inch thick. The density of gold is g/cm 3, and gold costs $1,670 per troy ounce (1 troy ounce = g). How much will it cost the architect to buy the necessary gold? Use Sci. notation. (1 in = 2.54 cm) Cost(USD) = 5. You are visiting Africa, and now you take a trip to Kampala the capital and largest city of Uganda. You want to go because you know the main campus of Makerere University (one of East and Central Africa s premiere institutes of higher education) is there, and you want to check it out! Flying to Kampala with a tailwind a plane averaged 158 km hr. On the return trip, the plane only averaged 112 km hr while flying back into the same wind. Find the speed of the wind and the speed of the plane in still air. V plain ( km hr ) = V wind ( km hr ) =

3 6. A thief plans to steal a gold sphere with a radius of 28.9 cm from a museum. If the gold has a density of 19.3 g/cm 3, what is the mass of the sphere in pounds? Is the thief likely to be able to walk off with the gold sphere unassisted? Use scientific notation. [V sphere = (4 3)πr 3 ] m(lb) = 7. A g sample of a solid is placed in a flask. Toluene, in which the solid is insoluble, is added to the flask so that the total volume of solid and liquid together is ml. The solid and toluene together weight g. The density of toluene at the temperature of the experiment is g/ml. What is the density of the solid? d solid ( g ml ) =

4 8. A sphere made of carbon has a volume of m 3. If you increase the radius of the sphere fourfold, what is the new volume of the sphere in cubic feet? V new (ft 3 ) = 9. A cylinder has a volume of m 3. If you increase the radius of the cylinder fourfold and its height fivefold. What is the new volume of the cylinder? Give your answer in cubic feet. (V = πr 2 h ; 1 m = yd ; 1yd = 3 ft) V new (ft 3 ) =

5 10. Gold is alloyed (mixed) with other metals to increase its hardness in making jewelry. (a) Consider a piece of gold jewelry that weighs 9.85g and has a volume of cm 3. The jewelry contains only gold and silver, which have densities of 19.3 g/cm 3 and 10.5 g/cm 3, respectively. If the total volume of the jewelry is the sum of the volumes of the gold and silver that it contains, calculate the percentage of gold (by mass) in the jewelry. (b) The relative amount of gold in an alloy is commonly expressed in units of carats. Pure gold is 24 karat, and the percentage of gold in an alloy is given as a percentage of this value. For example, an alloy that is 50% gold is 12 karats. State the purity of the gold jewelry in karats. mass% gold = purity(kt) =

6 11. An alloy called phosphor bronze is made of phosphorus, tin and copper. A particular phosphor bronze, containing 0.20% of phosphorus and 5.00% of tin by mass, can be used in cryogenics where fair electrical conductivity and low thermal conductivity are required. Use the following data, obtained from reputable sources on the internet, to find the cost of phosphorus per gram. Assume the cost of the alloy is only for the material. The alloy is sold in cylinders and you pay $ USD per foot of alloy (the diameter is 2.25 in). d Phosphor bronze = 8.87 g $3.27 ; Copper cm3 lb (1 kg = lb ; 1 t (tonne) = 1,000 kg) ; Tin $18,950 t (tonne) Cost of P ( $ g ) =