Equations Flashcards
Magnification and size of biological specimens using millimetres as units
Magnification = lens x times eyepiece x
eg 40 x 10 = magnification of 400
Density
Mass/volume
Hooke’s law
Force = constant x extension
F = kx
Photosynthesis
Carbon dioxide + water + energy in the presence of chlorophyll and sunlight -> glucose + oxygen
6CO2 + 6H2O -> C6H12O6 + 6O2
Aerobic respiration
Glucose + oxygen -> carbon dioxide + water + energy
C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy
Reactions of acids
Acid + metal oxide -> salt + water
Acid + metal hydroxide -> salt + water
Acid + metal -> salt + hydrogen
Acid + metal carbonate -> salt + carbon dioxide + water
Acid + metal hydrogen carbonate -> salt + carbon dioxide + water
Acid + ammonia solution -> ammonium salt + water
Salt = metal nonmetal
eg hydrochloric + sodium = sodium chloride+water
acid hydroxide
When hydrochloric acid is neutralised, the salt formed is a metal CHLORIDE
When nitric acid is neutralised, the salt formed is a metal NITRATE
When sulphuric acid neutralised, the salt formed is metal SULPHATE.
Litmus paper indications
Red Litmus Blue Litmus
Acidic solution Stays red Turns red
Neutral solution Stays red Stays blue
Alkaline solution Turns blue Stays blue
Electrode products in the electrolysis of:
- molten lead (ii) bromide
- aqueous copper chloride
Molten lead (ii) bromide PbBr2
Cathode
Pb2+ (l) + 2e- -> Pb (l)
Anode
2Br- (l) -> Br2 (g) + 2e-
- lead metal at the negative electrode
- The lead will form as a liquid at the bottom of the reaction vessel.
- bromine (Br2) at the positive electrode
- The bromine appears as a brown gas at the positive electrode.
Aqueous copper chloride
CuCl2 -> Cu + Cl2
At the cathode Cu is reduced
Cu2+ (aq) + 2e- -> Cu (s)
At the anode Cl is oxidised
2Cl- (aq) -> Cl2 (g) + 2e-
The products of this electrolysis are:
copper metal at the negative electrode
The copper forms as a brown solid on the negative electrode.
chlorine gas (Cl2) at the positive electrode
The chlorine appears as a gas with a characteristic smell at the positive electrode.
PRECIPITATION REACTIONS
Identify usings tests…
-Aqueous cations: copper (ii), iron (ii), iron (iii) and zine
-Anions: carbonate, chloride
-Gases: carbon dioxide, chlorine, hydrogen, oxygen
Aqueous cations:
- Copper (Cu2+). Effect of aq sodium hydroxide = light blue ppt. Insoluble in excess. Effect of aq ammonia = light blue ppt. Soluble in excess, giving a dark blue solution.
- Iron (Fe2+). Effect of aq sodium hydroxide = green ptt. Insoluble in excess. Effect of aq ammonia = green ppt. insoluble in excess.
- Iron (Fe 3+). Effect of aq sodium hydroxide = red-brown ppt. Insoluble in excess. Effect of aq ammonia = red-brown ppt, insoluble in excess.
Anions
- Carbonate. Add dilute acid, then limewater. Results = bubbles, CO2 produced.
- Choride. Acidify with dilute nitric acid, then add aqueous silver nitrate. White ppt
Gases
- Carbon dioxide. Turns limewater milky
- Chlorine. Bleaches damp litmus paper
- Hydrogen. “pops” with a lighted splint.
- Oxygen. Relights a glowing splint.
Name, identify and draw the structures of methane, ethane and ethene
Methane:
CH4
H
|
H - C - H
|
H
Ethane:
C2H6
H H
| |
H - C - C - H
| |
H H
Ethene:
C2H4
H H
\ /
C = C
/ \
H H
Sped (from total time/total distance)
S = d/t
Work out distance travelled in a speed/time graph
Area under the graph = distance.
What is -energy -work -power measured in.
Energy = joules (J)
Work done = joules (J)
Power = Watts (W)
Kinetic energy equation
K.E. = 1/2mv^2
= 1/2 x mass x velocity^2
Potential energy equation
P.E. = mgh
= mass x gravity x height.
Efficiency equation
Efficiency = (useful energy)/(total energy) x 100%
Gravity
10ms^-2
or 9.8
Work done equation
Work done = f x d
= force x distance
or work done = power x time
Acceleration
Vf - Vi
——- = a
time
Velocity
v = displacement / time
= change in position / time
Force
Force = Mass x acceleration
Power
P = work done / time
= (force x distance) / time
or
P = E/t
= energy/time
Current using Coulombs
I = Q/t
I is the current in amperes (amps), A
Q is the charge in coulombs, C
t is the time in seconds, s
Units of
- current
- electric charge
- time
- voltage
- energy
- power
Current: amps Electric charge: coulombs Time: seconds Voltage: volts Energy: Joules Power: Watts
Equation for resistance using potential difference and current
Resistance = potential difference / current R = p.d./I
Calculate the combined resistance of two or more resistors in series
R total = R1 + R2
Calculate resistance using voltage and current
R = V / I
Gravity in Newtons
10Nkg^-1
Moment equation
Moment = force x distance (perpendicular distance from the force to the pivot)
Moment in Newton metres
Force in Newtons
Distance in metres
Electrical Power
P = IV P = I^2R P = V^2 / R P = E/t
Electric Energy
E = IVt
Specific Heat Capacity
The specific heat capacity of a substance is the amount of energy needed to change the temperature of 1 kg of the substance by 1°C.
E = m × c × θ
E is the energy transferred in joules, J
m is the mass of the substances in kg
c is the specific heat capacity in J / kg °C
θ (‘theta’) is the temperature change in degrees Celsius, °C
Unbalanced force
F = ma
Weight
W = mg
g = 10N/kg
Wavelength
λ = v/f
λ= wavelength v = speed f = frequency
Law of reflection
Angle of Incidence = Angle of reflection
Electrical current
I = Q / t Q = coulomb of charge t = time
SulphIDE, sulphITE, and sulphATE
Sulphide = S2- Sulphite = SO3 ^2- Sulphate = SO4 ^2-
Power using force and velocity
P = Force x velocity
Current
I = q/t I = V/r
Voltage using energy in joules and coulombs
V = E/Q
Torque
Torque = force x distance
Refractive index
n = sin i / sin r
n = speed of light in air / speed of light in material
Speed of light
3 x 10^8 m/s
Frequency using the speed of light
F = c/λ λ = wavelength
c = fλ v = fλ
where c = speed of light
Units of frequency and wavelength
Frequency = Hz. Hertz
Wavelength in metres.
