C3.1 Flashcards
What is the principle of conservation of mass in chemical reactions?
No atoms are lost or created; the mass of reactants equals the mass of products
How do you balance a chemical equation?
Ensure the number of each type of atom is the same on both sides by adjusting coefficients.
What do state symbols (s), (l), (g), and (aq) stand for?
(s) = Solid
(l) = Liquid
(g) = Gas
(aq) = Aqueous (dissolved in water)
How do you determine the formula of an ionic compound?
Balance the positive and negative charges of the ions.
What is an ionic equation?
A simplified chemical equation that only shows the ions involved in a reaction, removing spectator ions.
What is Avogadro’s constant?
6.02 × 10²³ atoms, molecules, or ions in 1 mole of a substance.
How do you calculate moles from mass
Moles = Mass / Molar Mass (Mr)
What happens when metals react with oxygen?
They form metal oxides. Example: 2Mg + O₂ → 2MgO.
How do you write the formula for water?
H₂O – two hydrogen atoms and one oxygen atom.
How do you deduce the stoichiometry of an equation from masses?
Convert masses to moles, find the simplest whole-number ratio, and balance the equation.
What is a chemical formula?
A representation of a substance using chemical symbols and numbers to show the ratio of atoms.
What is the effect of a limiting reactant?
It determines how much product is formed since it is fully consumed first
What is the formula for sulfuric acid?
H₂SO₄ – contains hydrogen, sulfur, and oxygen.
What is a half-equation?
An equation showing the oxidation or reduction of a single species during a reaction
What happens when acids react with bases?
They form salt + water in a neutralization reaction.
What is the equation for a neutralization reaction?
H⁺ + OH⁻ → H₂O
What is the test for hydrogen gas?
A burning splint produces a squeaky pop sound.
What is the equation for a reaction between metal and acid?
Metal + Acid → Salt + Hydrogen
How do you know if a reaction has taken place?
Change in temperature, color, gas production, or formation of a precipitate.
Why do some reactions appear to have a change in mass?
Because gases may escape or enter, but total mass is conserved.
What is the relative atomic mass (Ar)?
The average mass of an atom compared to 1/12th of carbon-12.
What is an endothermic reaction?
A reaction that absorbs heat from the surroundings.
What is an exothermic reaction?
A reaction that releases heat to the surroundings.
What is the formula to calculate mass using moles?
Mass = Moles × Molar Mass (Mr)
