types of reactions?

Question

1.In a double-replacement reaction, ____.
a. the reactants are usually a metal and a nonmetal
b. one of the reactants is often water
c.the reactants are generally two ionic compounds in aqueous solution
d.energy in the form of heat or light is often produced

2. Mg(OH)2(s) → MgO(s) + H2O(g)


The type of reaction represented by the above equation is —
a.single-replacement
b.synthesis or combination
c.double-replacement
d.decomposition
e.combustion

3.The equation 2Cr(s) + 3Fe(NO3)2(aq) → 3Fe(s) + 2Cr(NO3)3(aq) is an example of which type of reaction?
a.decomposition reaction
b.synthesis or combination reaction
c.combustion reaction
d.single-replacement reaction
e.double-replacement reaction

4.When magnesium is heated in the presence of nitrogen gas, solid magnesium nitride forms.
What type of reaction takes place?
a.Single-replacement
b.Double-replacement
c.Synthesis or Combination
d.Decomposition
e.Combustion

Answer 1

1 - Gonna go with C
2 - D
3 - D
4 - C

Answer 2

1) c
2) d
3) d
4) c