Element A has a half-life of 10 days. A scientist measures out 200 g of this substance. After 30 days has passed, the scientist reexamines the sample.

How much Element A will remain in the sample?

50 g

25 g

12.5 g

100 g

A centrifuge was used to separate a sample into its components. What conclusion about the sample can be formed based on the technique used? It was a pure substance. It was a compound. It was a heterogeneous mixture. It was a homogeneous mixture

You are trying to determine the volume of the balloon needed to match the density of the air in the lab. You know that if you can get the balloon's density below this value, it will float.

Which of the following substance is not an acid? Substance A is tested and found to have a pH of 3. Substance B, a common food, tastes sour. Substance C causes metals to corrode. Substance D feels slippery in solution.

What are bricks made out of?

How many electrons are in the outermost shell of the ga3 + ion in its ground state?

A cube has a mass of 100 grams and it's density is determined to be 1g/cm^3. The volume of the cube must be

The oxide of titanium, TiO2 is used as a "whitener" in toothpaste. It is obtained from the ore iron (II) titanate, FeTiO3. What is the change, if any, in the oxidation number (oxidation state) of titanium in the reaction

What happened to the mars Climate Orbiter and why? How much money did NASA lose from this incident?

How many bonds are present in HCI? a) 1 b) 3 c) 4 d) 2

Determine the number of moles 1) 20g Na and 2) 34g H2O