4. Which of the following statements correctly describe atoms? Select all that apply.

A) Atoms have mass,

B) Atoms are the basic unit of a chemical element.

C) Matter is made of atoms.

D) Atoms take up space.

Identify the reaction type and balance it 3. _Zn + _HCI → _ZnCl2 + _H2

Name an element in the third period (row) of the periodic table with one valence electron.

Which is the control center for the endrocrine system?

Why does the rate of a chemical reaction typically decrease over time? A. The pressure decreases as the product is formed. B. The temperature decreases as the reaction continues. C. The effect of the catalyst decreases as the reaction continues. D.

If 3.0 liters of oxygen gas react with excess carbon monoxide at 273 K and 1.00 atm, how many liters of carbon dioxide can be produced under the same conditions? 2 CO (g) + O2 (g) yields 2 CO2 (g)

Calcium and sulfur ionic compound or non ionic?

Which of the following would release the most heat upon cooling from 75°C to 50°C?

Chlorine atoms each have 17 protons. How many neutrons does each Cl-37 atom have? A. 17 B. 20 C. 37 D. 54

Which choice can be a solid, liquid, or a gas? A. steel B. silver C. water D. carbon dioxide

How to convert 0.000984 into scientific notation?