when calcium (ca) is mixed with hydrochloric acid (hcl), calcium chloride (cacl2) and hydrogen (h2) form what type of reaction is this?

1. c. single replacement Ca is replacing H

2. d. combustion This question is badly worded. Not all reactions that use O2 and release energy are combustion reactions.

correct choices are
.. 1. c
.. 2. d

these are the GENERAL types of reactions you need to learn
.. (1) .. A + B ---> AB... .... ... ... synthesis
.. (2).. .AB ---> A + B.. .... ... .. ..decomposition
.. (3).. .AB + C ----> AC + B.. ... .single displacement
.. (4).. .AB + CD ---> AD + CB.. .double displacement
.. (5) .. CxHy + O2 ---> CO2 + H2O.. combustion

*** question #1 ***

your reaction
.. Ca + 2 HCl ----> CaCl2 + H2
is
.. ..A + BC -------> AC + B
and is
.. .Single displacement

*** question #2 ***

the answer your instructor is looking for is "combustion".. but O2 and exothermic doesn't always mean combustion.

this reaction
.. 4 Fe + 3 O2 ---> 2 Fe2O3
is NOT a combustion reaction. yet it is exothermic.

single rep

Ans : 2 b.