Practice problems (show all work): 1. how many significant figures are there in the following numbers? a. 0.008 = b. 9023 = c. 252.06 = 2. what is the volume of a salt crystal measuring 5.44 x 10-2m by 2.5 x10-3m by 7.9 x 10-3 m? 3. what is the quantity 750 milligrams expressed in grams? 4. what is the volume of 50.0 g of calcium if the density of calcium is .50 g/ml? 5. how did lavoisier transform the field of chemistry in the late 1700s?you.

Margaret wants to make an orange flavored drink by stirring powdered drink mix into a glass of water. she doesn't like drinks that have small clumps of powdered solid in them, so she wants the drink to be a perfect solution. what factors should margaret not consider when deciding how much powder to add to her glass of water?

Identify one disadvantage to each of the following models of electron configuration: -dot structures -arrow and line diagrams -written electron configurations type in your answer below. (answer) -dot structures do not show the distribution of electrons in orbitals and take up a lot of space. -arrow and line diagrams take up a lot of space and make it difficult to count electrons. -written configurations make it easy to lose count of electrons and do not show the distribution of electrons in orbitals.

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.