Describe the 2 kinds of pure substance

53) The mass of a calcium atom is due primarily to the mass of its A) protons, only B) neutrons, only C) protons and neutrons D) protons and electrons

If I contain 1.86g of krypton gas in a container with a volume of 17.5 liters and at a temperature of 190F, what is the pressure inside the container?

Which statement is true? A reaction in which the entropy of the system decreases can be spontaneous only if it is exothermic. A reaction in which the entropy of the system increases can be spontaneous only if it is endothermic.

How many grams are in 3 moles of HF?

When you have a solution with a high concentration of hydrogen ions, is it an acid or a base?

An aspirin tablet contains 81.0 mg of aspirin, which has the molecular formula, c9h8o4.

What size container do you need to hold 0.0459 mol of N2 gas at stp

What happens when two or more atoms react?

If cobalt metal is mixed with excess sulfur and heated strongly, a sulfide is produced that contains 55.06% cobalt by mass. Calculate the empirical formula of the sulfide.

Calcium's atomic number is 20. it forms ions with 18 electrons. what is the electrical charge of a calcium ion?