Chapter 7 Flashcards
(33 cards)
What is a gas evolution reaction?
A reaction in which a gas is produced as a product.
What is an example of a gas evolution reaction?
Baking soda (sodium bicarbonate) reacts with acetic acid (vinegar) to form carbon dioxide gas, water, and sodium acetate.
What is another example of a gas evolution reaction?
Zinc reacts with hydrochloric acid to form zinc chloride and hydrogen gas.
What is a combustion reaction?
A reaction in which a hydrocarbon reacts with oxygen to produce carbon dioxide and water, releasing heat and light.
What is an example of a combustion reaction?
Burning methane (CH4 + O2 → CO2 + H2O).
What is an example of a combustion reaction involving a solid hydrocarbon?
Burning paraffin wax: C31H64 + 92O2 → 31CO2 + 32H2O.
What is evidence of a chemical reaction?
Color change, formation of a solid (precipitate), formation of gas, emission of light, or heat absorption/release.
What is an example of a color change in a chemical reaction?
Potassium permanganate reacts with sugar and caustic soda, changing from purple to green to brown.
What is an example of precipitate formation in a chemical reaction?
Silver nitrate reacts with sodium chloride to form solid silver chloride (AgCl precipitate).
What is an example of gas formation in a chemical reaction?
Zinc reacts with hydrochloric acid to produce hydrogen gas bubbles.
What is an example of light emission in a chemical reaction?
Luminol reacts with hydrogen peroxide and emits light.
What is an example of a heat-absorbing reaction (endothermic)?
Baking soda and vinegar react, causing a temperature drop from ~19°C to ~16°C.
What is an example of a heat-releasing reaction (exothermic)?
Methane combustion releases heat used for cooking and heating.
What is NOT a chemical reaction?
Boiling water forms gas bubbles, but the water molecules remain unchanged.
What is another example of something that is NOT a chemical reaction?
Mixing NaCl solution with KBr solution results in a colorless solution without a chemical reaction.
What do (s), (l), (g), and (aq) mean in a chemical equation?
(s) = solid, (l) = liquid, (g) = gas, (aq) = aqueous (dissolved in water).
How do you balance a chemical equation?
Adjust coefficients to make the number of atoms of each element equal on both sides.
What is an example of a balanced chemical equation?
2HCl(aq) + K2CO3(aq) → H2O(l) + CO2(g) + 2KCl(aq).
What is a solution?
A homogeneous mixture of two or more substances (e.g., air, seawater, coffee).
What is an aqueous solution?
A solution where water is the solvent (e.g., seawater, soda, coffee).
What is the solvent in a saltwater solution?
Water.
What is the solute in a saltwater solution?
Salt (NaCl).
What is an electrolyte?
A substance that dissolves in water to produce ions and conduct electricity.
What is an example of an electrolyte?
NaCl dissolves in water to form Na+ and Cl- ions, conducting electricity.
