2.1.3 Amount of Substance Flashcards

1
Q

Definition of amount of substance

A

Number of particles in a substance (measured in moles)

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2
Q

Definition of mole

A

A unit of measurement containing 6.022 x 10^23 particles

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3
Q

Definition of molar mass and units

A

mass per mole g mol-1

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4
Q

Definition of molar gas volume

A

gas volume per mole dm3 mol-1

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5
Q

Definition of empirical formula

A

Simplest whole number ratio of atoms of each element in a compound

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6
Q

Definition of molecular formula

A

number and type of atoms of each element in a molecule

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7
Q

Definition of water of crystallisation

A

The water that is part of the crystalline structure (water that is locked in between the ions of an ionic lattice)

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8
Q

Definition of anydrous

A

Substance that contains no water of crystallisation

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9
Q

Definition of hydrated

A

Substance that contains water of crystallisation

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10
Q

% by mass of N In NH4NO3

A

35.0%

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11
Q

Equation for percentage atom economy

A

Percentage Atom Economy=((Mr of desired product)/(Total Mr of all products))×100

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12
Q

% by mass of O in CuSO4.5H2O

A

57.7

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13
Q

Bromomethane is reacted with sodium hydroxide to make methanol.
CH3Br + NaOH → CH3OH + NaBr
Calculate the percentage atom economy for this reaction.

A

23.7%

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14
Q

How many atoms are in two moles of atoms

A

1.2 x 10^24

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15
Q

How many electrons are in one mole of sodium atoms?

A

6.62x10^24

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16
Q

In the ionisation of 2 moles of Ne, how many electrons are released?

A

1.2 x 10^24

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17
Q

How many protons are there in 3 moles of nitrogen gas?

A

2.5 x 10^25

18
Q

how many moles of CO2 are there 11 g of carbon dioxide? How many moles of C atoms? How many moles of O atoms?

A
n(CO2) = 0.25
n(C) = 0.25
n(2) = 0.50
19
Q

What mass of magnesium oxide is formed by the complete combustion of 12 g of magnesium?

20
Q

8) What mass of potassium oxide is formed when 7.8 mg of potassium is burned in oxygen?

A

9.4 x 10^-3 g (9.4 mg)

21
Q

In the manufacture of titanium, what is the limiting reagent and what mass of titanium can theoretically be formed when 1 kg of titanium chloride reacts with 0.1 kg of magnesium?

A

98.6 g

Mg is the limiting reagent.

22
Q

Equation for percentage yield

A

actual yield/theoretical yield x100

23
Q

2.3g of sodium reacts with an excess of chlorine to produce 4.0g of sodium chloride. What is the percentage yield?

24
Q

40.0 g of Fe2O3 was found to produce 16g of iron metal. Calculate the percentage yield and the atom economy.

A

PY=57% AE=52%

25
A compound contains 50% of sulphur combined with 50% of oxygen. Calculate the empirical formula.
SO2
26
50.0 g of a compound contains 22.4 g of potassium, 9.2 g of sulphur, and the rest oxygen. Calculate the empirical formula of the compound.
K2SO4
27
3.53 g of iron reacts with chlorine to form 10.24 g of iron chloride. Find the empirical formula of the iron chloride.
FeCl3
28
5. An oxide of phosphorous contains 56.4% phosphorous and 43.6% oxygen. Its Mr is 220. Find both the empirical and the molecular formula of the oxide.
EF= P2O3 MF= P4O6
29
4. A compound contains 40.0 % of carbon 6.7 % of hydrogen and oxygen. It has a relative molecular mass of 60. Determine both the empirical and molecular formula of the molecule.
EF= CH2O MF= C2H4O2
30
10.00 g of hydrated barium chloride is heated until all the water is driven off. The mass of anhydous compound is 8.53 g. Determine the value of x in BaCl2.xH2O
x=2
31
5) Nickel combines with carbon monoxide to form nickel carbonyl, Ni(CO)x .When 2.95 g of Ni was warmed gently in carbon monoxide it was converted completely into 8.55 g of nickel carbonyl. Find the mass of carbon monoxide which has combined with the 2.95 g of Ni and then deduce the value of x in the formula
x=4
32
What is the ideal gas equation
PV=nRT
33
What units should each term of the ideal gas equation be in
``` P = Pa V = m3 T = K ```
34
Covert each of the following to m3: 20 000 cm3 0.15 cm3 2.8 dm3
0. 02 1. 5x10^7 2. 8 x 10^-3
35
Convert each of the following to Pa: 1 atm 0.02 atm 0.3 kPa
101000 2020 300
36
Convert each of the following to K: 180 oC -40 oC
453 K | 233 K
37
A gas sample whose relative molecular mass is 153, occupies 1550 cm3 at room temp and pressure. What is the mass of the gas sample
n=0.064 mol, mass = 9.83 g
38
0.800g of a gas was placed into a vessel of volume 0.950 dm3 at a temperature of 298K. The gas was found to exert a pressure of 0.550 atmospheres. Calculate the relative molecular mass of the gas
n = 0.021 mol, Mr = 37.6 g mol-1
39
What volume of gas is produced when 82.75g of lead (II) nitrate is thermally decomposed at 101 kPa and 100 o C.
n(Pb(NO3)2 = 0.25, n(gas products) = 0.62 mol, V=0.0192 m3
40
Nitromethane, CH3NO2, burns in oxygen forming three gases. 2CH3NO2(l) + 1½ O2(g) --> 2CO2(g) + 3H2O(g) + N2(g) A 100g sample of nitromethane was completely burned in oxygen. Calculate the total volume of gaseous products at 400K and 100kPa.
n(CH3NO2) = 1.64, n(gas products) = 4.92 mol, V= 0.16 m3
41
``` What mass of potassium chlorate (V) must be heated to give 1.00 dm3 of oxygen at 20.0ºC and 100 kPa. 2 KClO3(s) → 2 KCl(s) + 3 O2(g) ```
n(O2) = 0.041 mol, 2735g