What is the density of a object with a mass of 34 g and a volume of 4 cm3?

Answer 1

To answer this type of question, you should look at the units of the answer, and the units of the information you have. Then you need to figure out how to come up with the units of the answer using the units of your given information. For example, if you wanted to know how many square inches is in a 9inch by 5 inch rectangle, you'd look at the units of the answer (square inches) and the units of the given information (9 inches and 5 inches). To get square inches, you multiply them together, and discover that the rectangle contains 45 square inches. Let's use this method on your question. Density is measured in units of mass per unit of volume. The standard (metric system) way of putting it is in kilograms per cubic meter, but it will work with other units too. For example, (US measurements) pounds per gallon. We'll use grams per cubic centimeter, since it makes the problem easy. I'll show you how to turn it into the standard form later. Here we go! Density is in grams per cubic centimeter. We have 34 grams, and we have 4 cubic centimeters. To get grams per cubic centimeter, just divide 34 grams by 4 cubic centimeters, which gives us 8.5 grams per cubic centimeter. To convert to kilograms per cubic meter, you multiply by the appropriate conversion factors in such a way as to cancel out the units you have (grams, centimeters) leaving the units you want (kilograms, meters). The conversion factors you need are: 100 cm per 1 meter and 1000 grams per 1 kilogram You can also write these the other way around, if it makes it easier. You can also square them, or cube them. We'll want the cubed version of the first conversion factor: (100 cm)^3 / (1 m)^3 or 1,000,000 cm^3 / 1 m^3 Let's put it together. We'll write everything as fractions so it's easy to cancel the units. 8.5 g / cm^3 * (1 kg/1000 g) * (1,000,000 cm^3 / 1m^3) = 8.5 / 1000 * 1,000,000 = 8500 kg / m^3 That's about the density of brass. Fairly dense. Hope this helps, Gdunge