4 Chemical Reactions and Equations Free Online FlashCards

What happens to substances in a chemical reaction?

Reactants are changed into new substances called products as atoms rearrange and chemical bonds break and form.

What do the arrow and plus sign mean in a chemical equation?

The arrow means “yields” or “forms.” A plus sign separates substances that react together or are produced together.

What does the law of conservation of matter say about a chemical reaction?

Matter is conserved: atoms are rearranged, not created or destroyed. In a closed system, reactant mass equals product mass.

What products form in complete combustion of a hydrocarbon?

Combustion is reaction with oxygen. Complete combustion of a hydrocarbon produces carbon dioxide and water.

What do coefficients represent about the amounts of substances?

Coefficients show relative numbers of particles or, at laboratory scale, relative amounts in moles; they do not represent equal masses of each substance.

What is the balanced form of $\mathrm{Al+O_2\rightarrow Al_2O_3}$?

The balanced equation is $\mathrm{4Al}+3\mathrm{O_2}\rightarrow2\mathrm{Al_2O_3}$.

What happens in a synthesis reaction?

Synthesis combines simpler substances into a compound, following the pattern $\mathrm{A+B\rightarrow AB}$.

What happens in a decomposition reaction?

Decomposition occurs when one substance breaks apart into simpler substances, following $\mathrm{AB\rightarrow A+B}$.

What changes in a single-replacement reaction?

In single replacement, one element replaces another in a compound. For example, zinc replaces hydrogen: $\mathrm{Zn+2HCl\rightarrow ZnCl_2+H_2}$.

What happens in a double-replacement reaction?

In double replacement, ions in two compounds exchange partners, as in $\mathrm{AgNO_3+NaCl\rightarrow AgCl+NaNO_3}$.

What is a precipitate?

A precipitate is an insoluble solid formed in a reaction; silver chloride, $\mathrm{AgCl(s)}$, is one example.

What physical states do (s), (l), (g), and (aq) indicate?

The symbols indicate physical state: (s) solid, (l) liquid, (g) gas, and (aq) dissolved in water.