What is the atomic number for an abundant element with mass number 12?

Using the periodic table, which of the following elements has the most properties in common with calcium (Ca) ? potassium (K) magnesium (Mg) scandium (Sc) argon (Ar)

Eva pumps up her bicycle tire until it has a gauge pressure of 413 kilopascals. If the surrounding air is at standard pressure, what is the absolute pressure in the bicycle tire?

The following chemical equation is not balanced: CaCl2 + AgNO3 - > AgCl + Ca (NO3) 2 when this chemical equation is correctly balanced what is the coefficient of the silver chloride molecule? A) 1 B) 2 C) 3 D) 4

What is the balanced equation for S8 + O2 →SO3

Which will not appear in the equilibrium constant expression for the reaction below

Which of the following represents a chemical change? Bending a wire Freezing of water Fireworks exploding Melting of a wax candle

5.00 L of a gas is collected at 100K and then allowed to expand to 20.0 L. What must the new temperature be in order to maintain the same pressure? A. 400 °C B. 127 °C C. 223 °C D. 627°C

Before the initial explosion was the matter hot or cold

Which of the following atoms has seven valence electrons? chlorine (Cl) nitrogen (N) manganese (Mn) oxygen (O)

A.) During an experiment, a student adds 2.90 g of CaO to 400.0 mL of 1.500 M HCl. The student observes a temperature increase of 6.00 °C. Assuming the solution/'s final volume is 400.0 mL, the density if 1.00 g/mL, and the heat capacity is 4.