Formulae, Equations And Amounts Of Substance Flashcards

1
Q

Define a mole

A

Unit for amount of substance: the amount of chemical species found in 12g of carbon-12

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2
Q

What is Avogadro’s constant?

A

Number of atoms in exactly 12g of carbon-12.

6.02 x 10^23

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3
Q

Define molar mass

A

Mass of 1 mole of the substance in g/mol

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4
Q

Define relative molecular mass

A

Average mass of a molecule relative to 1/12 mass of carbon-12 atom

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5
Q

Define empirical formula

A

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

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6
Q

Define molecular formula

A

Actual number of atoms of each element in a molecule

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7
Q

Define spectator ion

A

Ions that do not take part in the reaction

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8
Q

What is a hydrate?

A

A compound that has waters of crystallisation

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9
Q

What is a standard solution?

A

One with an accurately known concentration

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10
Q

What is mass concentration?

A

Mass of solute per volume unit of solution - gdm^-3

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11
Q

What is molar concentration?

A

Moles of solute per volume of solution - moldm^-3

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12
Q

What is a primary standard?

A

A substance used for preparation of a standard solution

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13
Q

What is Avogadro’s law?

A

Provided the conditions of temperature and pressure are the same, equal volumes of gas contain the same number of molecules

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14
Q

What is molar volume?

A

Volume of 1 mole of gas

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15
Q

What is a displacement reaction?

A

A more reactive element reacts to take the place of a less reactive element in a compound

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16
Q

What is a precipitation reaction?

A

One that produces an insoluble solid (precipitate)

17
Q

What is an error?

A

A discrepancy between the value obtained in an experiment and the actual value

18
Q

What is precision?

A

Reference to how close each value is to each other obtained in an experiment

19
Q

What is accuracy?

A

Reference to how close obtained values are to the actual value

20
Q

What are concordant results?

A

Results that lie close to each other, usually titrates that lie within 0.20cm^3 (+/- 0.10cm^3)

21
Q

What is a margin of error?

A

The range in which the true values could lie

22
Q

What are random errors?

A

They occur when conditions are varied in an unpredictable manner

23
Q

What are systematic errors?

A

Errors which are constant when you repeat an experiment, usually result of an apparatus used

24
Q

What is the equation for percentage uncertainty?

A

(Actual yield / theoretical yield) x 100 (%)

25
What is atom economy?
Measure of the proportion of atoms that become part of the desired product in the balanced chemical equation
26
What is the equation for atom economy?
(Mr of desired product / total Mr of all products) x 100 (%)
27
What does each letter of the pv = nRT equation represent?
``` p = pressure (Pa) v = volume (m^3) n = moles (mol) R = ideal gas constant: 8.314 T = temperature (k) ```