Question

Which reactions performed in the experiment

involved chemical changes?
O crushing calcium carbonate
mixing calcium carbonate and HCI
boiling water
heating copper sulfate pentahydrate
separating iron filing and sulfur
mixing potassium iodide and lead nitrate
combining magnesium and HCI
burning the candle
DONE
Intro

Answer 1

mixing calcium carbonate and HCI

heating copper sulfate pentahydrate

mixing potassium iodide and lead nitrate

combining magnesium and HCI

burning the candle

Answer 2

Answer: mixing calcium carbonate and HCI

heating copper sulfate pentahydrate

mixing potassium iodide and lead nitrate

combining magnesium and HCI

burning the candle

Step-by-step explanation:

A physical change is defined as a change in which there is alteration in shape, size etc. No new substance gets formed in these reactions. Example: Melting of ice

A chemical change is defined as a change in which a change in chemical composition takes place. A new substance is formed in these reactions. Example: Corrosion of iron

a) crushing calcium carbonate is a physical change as there is only a change in size.

b) mixing calcium carbonate and HCI : is a chemical change as there is formation of new substances.

`CaCO_3+HCl\rightarrow CaCl_2+H_2O+CO_2`

c) boiling water is a physical change as there is only a change in state.

d) heating copper sulfate pentahydrate: is a chemical change as there is breaking of bonds.

`CuSO_4.5H_2O\rightarrow CuSO_4+5H_2O`

e) separating iron filing and sulfur : is a physical change as there is only separation of components.

f) mixing potassium iodide and lead nitrate: is a chemical change as there is formation of new substances.

`2KI+Pb(NO_3)2\rightarrow PbI_2+2KNO_3`

g) combining magnesium and HCI: is a chemical change as there is formation of new substances.

`Mg+2HCl\rightarrow MgCl_2+H_2O`

h) burning the candle : is a chemical change as there is formation of new substances.