Question

which of the following equations shows a chemical change? (1 point)

c3h8 + 5o2 → 3co2 + 4h2o

nh3(g) → nh3(l)

c2h5oh(l) → c2h5oh(g)

h2o(s) → h2o(g)

Explanation:

A chemical change involves the formation of new substances. In the equation \(C_{3}H_{8}+5O_{2}\to3CO_{2}+4H_{2}O\), propane (\(C_{3}H_{8}\)) reacts with oxygen (\(O_{2}\)) to form carbon dioxide (\(CO_{2}\)) and water (\(H_{2}O\)), which are new substances. The other equations (\(NH_{3}(g)\to NH_{3}(l)\), \(C_{2}H_{5}OH(l)\to C_{2}H_{5}OH(g)\), \(H_{2}O(s)\to H_{2}O(g)\)) represent physical changes (changes in state - gas to liquid, liquid to gas, solid to gas respectively) where no new substances are formed.

Answer:

\(C_{3}H_{8}+5O_{2}\to3CO_{2}+4H_{2}O\)