HEL Match the chemical equations to the appropriate types of chemical reactions

1. 8Cu + S8-8 Cus (synthesis or decomposition reaction)

2. P4 +502-2P205 (synthesis or decomposition reaction)

3. BaCO3-BaO + CO2 (synthesis or decomposition reaction)

4. KCIO3—KCI + O2 (synthesis or decomposition reaction)

5. 8Fe + S8- 8Fes (synthesis or decomposition reaction)

6. H2CO3—H2O + CO2 (synthesis or decomposition reaction)

Which of the following did jj thompson discover about atoms? a)an atom has an internal structure. b) atoms are tiny indivisible particles. c)electrons orbit the nucleus of an atom. d) the nucleus of an atom contains protons and neutrons.

The volume of helium in a blimp is 6.28 x 10^9 millimeters. the density of helium in the blimp is .1786 kilogram/meter^3. find the mass of the helium in the blimp.

Modern pennies are composed of zinc coated with copper. a student determines the mass of a penny to be 2.482 g and then makes several scratches in the copper coaling (to expose the underlying zinc). the student puts the scratched penny in hydrochloric acid, where the following reaction occurs between the zinc and the hcl (the copper remains undissolved): zn(s) + 2 hcl(aq) → h2(g) + zncl(aq)the student collects the hydrogen produced over water at 25 °c. the collected gas occupies a volume of 0.899 l at a total pressure of 79 j mmhg. calculate the percent zinc (by mass) in the penny. (assume that all the zn in the penny dissolves.)