Chemical Reactions Flashcards
(26 cards)
What evidence is observed when a chemical reaction has taken place?
Temperature Colour Shape Size Odour
Difference between products and reactants
Product-produced substance Reactants- reacting substance Example: sodium hydroxide+hydrochloric acid —> water+sodium chloride (NaOH+HCL—>H2O+NaCL) REACTANTS on the LEFT PRODUCTS on the RIGHT
Chemical reaction definition
Two or more substances react to produce a new chemical substance
Difference between a spontaneous and non spontaneous chemical reaction?
Spontaneous- they begin immediately after the two reactants are brought together. Eg) vinegar and baking soda Non spontaneous- they require a kick start in the form of energy, usually heat or light. Eg) magnesium and oxygen
Difference between a chemical change and a physical change
Chemical change- (chemical reaction) one or more new substances are produced The bonds between atoms are broken and new bonds are formed eg) burning paper, baking cake Physical change- produced no new substances there is merely a change of state, shape or size No bonds between atoms are broken Eg) melting ice, boiling water, blowing up a balloon, stretching rubber band
States of matter
S-solid (fixed shape and volume, strongly bonded, can’t be compressed) L-liquid (takes containers shape, weakly bonded, can’t be compressed) G-gas (no fixed shape, fills the container, easily compressed) Aq- aqueous solution (when a solute(solid particle)is dissolved in water)
Word equation and chemical equation for photosynthesis
Photosynthesis is a exothermic reaction Word equation- carbon dioxide+water—>glucose+oxygen Chemical equation- 6CO2(g)+6H2O(l)—>C6H12O6(aq)+6O2(g)
Word equation and chemical equation for respiration
Respiration is a exothermic reaction Word equation- glucose+oxygen—>water+energy Chemical equation- C6H12O6(aq)+6O2(g)—>6CO2(g)+6H2O(l)
Law of conservation of mass
Matter cannot be created or destroyed, it is simply transfer from one form to another There are no atoms gained or lost, they are just rearranged Total mass of reactants= total mass of products
Definition of acids
Acids- corrosive substances Sour taste pH of 0-7 (less than 7) Donate hydrogen ions (H+) (protons) Example of acids- hydrochloric acid, vinegar, lemons, soda, coffee, milk
Definition of bases
Bitter taste Slippery or soapy Alkalis pH of 7-14 (more than 7) Accept hydrogen ions (H+) (protons) Examples of bases- dishwashing liquid, oven spray, cloudy ammonia, caustic soda, bicarbonate of soda, toothpaste
Common acids sheet
Ascorbic acid- vitamin C Lactic acid- causes muscle soreness Hydrochloric acid- stomach acid Sulphuric acid- common lab, found in car batteries Acetic acid- vinegar Formic acid- ant stings Citric acids- citrus fruits
Alkaline solution
Alkaline solution is a substance that is basic, and can be dissolved in water
Indicator colour changes for bases
Bases litmus paper=blue Phenolphthalein= pink Methyl orange= orange/yellow
Indicator colour changes for acids
Acids Litmus paper=red Phenolphthalein= colourless Methyl orange= red
Indicator definition and examples
An indicator is a substance which tells us whether a acid or base is present on the basis of colour change. Examples of indicators- red cabbage indicator, natural indicators include: blue litmus paper, red litmus paper, universal indicator. synthetic indicators include: phenolphthalein, methyl orange
Neutralisation definition
Acids and bases react quantitatively with each other. Getting the solution to the pH of 7 (neutral) Acid and base react to produce salt and water Acid+base(reactants)—> salt+water(products) Sodium hydroxide+Hydrochloric acid—>sodium chloride+water
Neutralisation word equation formulas
Examples 1. SODIUM hydroxide+HydroCHLORIC acid—>SODIUM CHLORIDE+water 2. SODIUM hydroxide+NITRIC acid—>SODIUM NITRATE+water 3.SODIUM hydroxide+SULPHURIC acid—> SODIUM SULPHATE+water Rule: first word of the first reactant plus first word of the second reactant=first word+first word+water
What is pH measuring, understand pH scale
To know how acidic or basic a substance is by using numbers or the pH scale 0-14 0-3 strong acidic 4-6 weak acidic 7 neutral 8-11 weak basic 11-14 strong basic
Universal indicator
It can determine not just whether something is an acid or base but also acidic and how basic the substance is. Universal indicator changes colour at pH’s ranging from 0-14
Red cabbage indicator
pH scale ranges from 0-12 0-2 red 2-4 purple/pink 4-6 violet 7 blue 8-10 blue/green 10-12 green/yellow
EXOthermic reactions
Give off heat Feel warm Stored as energy then released as heat Less energy stored Chemical energy—> heat energy Eg) sunlight, condensation, making ice cubes, candle flame
ENDOthermic reaction
Take in heat Feel cool Small amount of heat stored Absorbs energy More energy stored Heat energy—> chemical energy Eg) cooking an egg, evaporation, melting ice cubes
Redox reactions
Oxidation reaction and reduction reaction, involve a transfer of electrons Burning fuels is a type of redox reaction called combustion
