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Flashcards in Equations Deck (46):
1

Magnification and size of biological specimens using millimetres as units

Magnification = lens x times eyepiece x
eg 40 x 10 = magnification of 400

2

Density

Mass/volume

3

Hooke's law

Force = constant x extension

F = kx

4

Photosynthesis

Carbon dioxide + water + energy *in the presence of chlorophyll and sunlight* -> glucose + oxygen

6CO2 + 6H2O -> C6H12O6 + 6O2

5

Aerobic respiration

Glucose + oxygen -> carbon dioxide + water + energy

C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy

6

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.

7

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

8

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.

9

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.

10

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

11

Sped (from total time/total distance)

S = d/t

12

Work out distance travelled in a speed/time graph

Area under the graph = distance.

13

What is
-energy
-work
-power
measured in.

Energy = joules (J)
Work done = joules (J)
Power = Watts (W)

14

Kinetic energy equation

K.E. = 1/2mv^2
= 1/2 x mass x velocity^2

15

Potential energy equation

P.E. = mgh
= mass x gravity x height.

16

Efficiency equation

Efficiency = (useful energy)/(total energy) x 100%

17

Gravity

10ms^-2
or 9.8

18

Work done equation

Work done = f x d
= force x distance

or work done = power x time

19

Acceleration

Vf - Vi
------- = a
time

20

Velocity

v = displacement / time
= change in position / time

21

Force

Force = Mass x acceleration

22

Power

P = work done / time
= (force x distance) / time

or
P = E/t
= energy/time

23

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

24

Units of
-current
-electric charge
-time
-voltage
-energy
-power

Current: amps
Electric charge: coulombs
Time: seconds
Voltage: volts
Energy: Joules
Power: Watts

25

Equation for resistance using potential difference and current

Resistance = potential difference / current
R = p.d./I

26

Calculate the combined resistance of two or more resistors in series

R total = R1 + R2

27

Calculate resistance using voltage and current

R = V / I

28

Gravity in Newtons

10Nkg^-1

29

Moment equation

Moment = force x distance (perpendicular distance from the force to the pivot)
Moment in Newton metres
Force in Newtons
Distance in metres

30

Electrical Power

P = IV
P = I^2R
P = V^2 / R
P = E/t

31

Electric Energy

E = IVt

32

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

33

Unbalanced force

F = ma

34

Weight

W = mg

g = 10N/kg

35

Wavelength

λ = v/f

λ= wavelength
v = speed
f = frequency

36

Law of reflection

Angle of Incidence = Angle of reflection

37

Electrical current

I = Q / t
Q = coulomb of charge
t = time

38

SulphIDE, sulphITE, and sulphATE

Sulphide = S2-
Sulphite = SO3 ^2-
Sulphate = SO4 ^2-

39

Power using force and velocity

P = Force x velocity

40

Current

I = q/t
I = V/r

41

Voltage using energy in joules and coulombs

V = E/Q

42

Torque

Torque = force x distance

43

Refractive index

n = sin i / sin r

n = speed of light in air / speed of light in material

44

Speed of light

3 x 10^8 m/s

45

Frequency using the speed of light

F = c/λ
λ = wavelength

c = fλ
v = fλ

where c = speed of light

46

Units of frequency and wavelength

Frequency = Hz. Hertz
Wavelength in metres.