Which of the following is a balanced chemical reaction? A 1H_(2)O_(2)grave (a)1H_(2)O+1O_(2) B 2H_(2)O_(2)grave (a)2H_(2)O+O_(2) C 2H_(2)O_(2)grave (a)1H_(2)O+2O_(2) D 4H_(2)O_(2)grave (a)4H_(2)O+2O_(2)

30) Which one of these elements is NOT a diatomic? iodine hydrogen bromine

Explain why the valence electrons are important in determining the chemical properties of an element. They are involved in chemical bonding. They determine the element's color. They determine the atomic mass. They are located in the nucleus.

8. Arrange the following molecules in order of increasing boiling points: CH_(4),CO_(2),HF,NaCl,Kr,PH_(3)

4x A chemical reaction for the reaction of Sodium Hydroxide (NaOH) and Hydrochloric Acid (HCl)is shown. The masses of some of the reactants and products are given in grams. NaOH+HClarrow NaCl+H_(2)O 16g 24912g ? How many grams of water were produced in the reaction? A 189 B 289 C 409 D 529

3. In the lab what was the mass of the steel wool after burning? 1.5149 1.426 g 23479 2.7649 4. Why does steel wool burn, but not an iron rod? The steel wool increased the surface area between reactants, which increased the rate of reaction. The steel wool decreased the surface area between reactants, which decreased the rate of reaction. 5. Why does the steel wool weigh more after the reaction? because oxygen was added during the reaction. it didn't weigh more because energy was created