Describe one everyday situation in which it would be useful to identify an unknown substance

Which of the following Group 1A elements is the least reactive? A. Cs (cesium) B. Li (lithium) C. K (potassium) D. Na (sodium)

And h is the half-life, in days, of the substance. a scientist has a 10-mg sample of a radioactive isotope. the isotope has a half-life of 8 days. after 16 days, how much of the radioactive isotope remains?

2. Calculate the molarity of a solution if there are 1.5 mol of NaCl in 2.3 L of solution.

You add 7.8 g of iron to 20.70 mL of water and observe that the volume of iron and water together is 21.69 mL. Calculate the density of iron.

What is the concentration of hydroxide ions in a solution with a pH of 5.24? 5.75 * 10-6 1.74 * 10-9 1.55 * 10-7 4.54 * 10-4

Which average wind speed do areas need to effectively power wind farms? A:1 mph B:5 mph C:10 mph D:16 mph

What is the total number of moles represented by 20 grams of CACO3 A. 0.1 B. 0.2 C. 1 D. 2

Which describes the polarity in a water molecule? a). partial negative charge on the oxygen atom because its electrons are pulled toward the hydrogen atoms b).

To what temperature in kelvin will a 2.3 L balloon have to be heated to expand to a volume of 400 L Assume the initial temperature of the balloon is 25 degrees celsius.

In which changes of state do atoms lose energy?