Y10 Autumn Term Chemistry Roundup Flashcards
What can you do to measure the rate of a reaction?
To measure the rate of a reaction you can:
- Measure how fast the reactants are used up
- Measure how fast the products are made
Name some examples of how you can measure the rate of reaction.
1) Measure mass due to gas formed
2) Measure volume of gas produced
3) Measure time for soluble product to form
What is the equation for working out the rate of a reaction?
Rate = Volume of gas / time (cm/s)
What is collision theory?
Collision theory is the term for what is needed for a reaction to take place
What do the reactants need to do for a reaction to happen?
The reactants need to:
- Collide with enough energy (activation energy)
- A successful collision is one that leads to a reaction
- So to increase the rate of reaction you must either:
a) Increase the frequency/energy of collisions
b) Decrease the energy needed for a collision to be successful
- Factors that effect the rate are concentration + pressure
- The more particles there are in the same space the more collisions will happen
How does surface area effect the rate of reaction?
The more particles that are available to react = the more frequently collisions will occur
How does temperature effect the rate of reaction?
Particles move faster so they collide more frequently. Particles collide with more energy so more collisions are successful.
How do catalysts effect the rate of reaction?
- Lower energy needed for successful collisions
- Not used up
- Biological catalysts = enzymes
What are reversible reactions?
Reactions that can go in both directions. If a reaction is exothermic one way it’ll be endothermic in the other.
What is a closed system?
A system where nothing can get in or out
What is equilibrium?
Equilibrium is where the rate of reaction is the same on both sides
What happens at equilibrium?
- Rate of forward reaction = rate of backward reaction
- Amount of products + reactants don’t change
Name the metals of the reactivity scale in order of most to least reactive
Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Carbon
Zinc
Iron
Tin
Lead
Hydrogen
Copper
Silver
Gold
Platinum
What does reactivity depend on?
Reactivity depends on tendency to form a metal ion
What are other names for positive and negative ions
Cations (positive) + Anions (negative)
What does OILRIG stand for?
Oxidation
Is
Loss of electrons
Reduction
Is
Gain of electrons
What happens to metals when you react them with:
a) Oxygen
b) Water
c) Acid
a) Metal oxide
b) Metal hydroxide + hydrogen
c) Metal salt + hydrogen
What happens to acids when you react the with:
A) metal
B) alkali
C) insoluble gas
D) carbonate
A) salt + hydrogen
B) salt + water
C) salt + water
D) salt + water + carbon dioxide
How do you prepare a dry sample of a soluble salt?
1) Choose correct acid + Add base to excess
2) Warm
3) Filter off excess
4) Evaporate of water
Which number(s) are considered acidic on the pH scale?
1-6
Which number(s) are considered neutral on the pH scale?
7
Which number(s) are considered alkaline on the pH scale?
8-14
What happens to strong acids in water
- Completely ionises in water
- Breaks down fully into ions
- Hydrogen = positive
What happens to weak acids in water?
- Only partially ionises in water
- Only some acid molecules split up
- Amount of H+ ions = less pH is higher
What is electrolysis?
Electrolysis is a technique that uses direct electric current to drive an otherwise non-spontaneous chemical reaction using negative non-metal ions + positive metal ions
What happens at the cathode of electrolysis of molten?
Pb 2+ + 2e- ——> Pb
What happens at the anode of electrolysis of molten?
2Br- ——> Br2 + 2e-
or
2Br- — 2e- —> Br2
What happens at the cathode of electrolysis of solutions?
Least reactive
What happens at the anode of electrolysis of solutions?
Halide (Gp 7) + Oxygen
What is quantitative chemistry? (1)
The law of conservation of mass states that no atoms are lost/made during a chemical reaction so the mass of the products = mass of the reactants.
What is quantitative chemistry? (2)
In a balanced equation, the sum of the relative formula masses of the reactants in the quantities shown = the sum of the relative formula masses of the products in the quantities shown.
What is quantitative chemistry? (3)
When a metal reacts w/ oxygen the mass of the oxide produced > the mass of the metal.
What is quantitative chemistry? (4)
In thermal decompositions of metal carbonates, carbon dioxide is produced + escapes into the atmosphere leaving the metal oxides as the only solid product.
What is quantitative chemistry? (5)
The masses of the reactants + products can be calculated from balanced (symbol) equations. Chemical equations can be interpreted in terms of moles. Shows that 1 mole of magnesium reacts w/ 2 moles of hydrochloric acid to produce 1 mole of magnesium chloride + 1 mole of hydrogen gas.
What is quantitative chemistry? (6)
In a chemical reaction involving 2 reactants, it’s common to use an excess of 1 of the reactants to ensure that all of the other reactant is used up.
What is quantitative chemistry? (7)
The percentage atom economy of a reaction is calculated using the balanced equation.
What is Avogadro Constant?
The number of atoms/molecules/ions in a mole of any substance
What is a Mole?
The amount of substance in the relative atomic/formula mass of a substance in grams. Unit symbol = mol.
What is Concentration?
The amount of substance dissolved in a given volume of liquid.
What is a Limiting Reactant?
The reactant in a chemical reaction that when used up causes the reaction to stop.
What is Percentage Yield?
The actual mass of of product collected in a reaction / the maximum mass that could’ve been formed in theory x 100. Amount obtained = yield.
What is Relative Formula Mass (Mr)?
The total of the relative atomic masses added up in the ratio shown in the chemical formula of substance.
What is Relative Atomic Mass (Ar)?
The average mass of the atoms of an element compared w/ carbon (=12). The average mass must take into account the proportions of the naturally occurring isotopes of the element.
What is the formula triangle for this?
Mass = moles x Mr
