C5 Flashcards

1
Q

Recall the formula of hydrochloric acid, ethanoic acid, carbon dioxide, hydrogen, water, sodium chloride, potassium chloride, ammonia and calcium carbonate

A

HCl, CH3COOH, CO2, H2, H2O, NaCl, KCl, NH3, CaCO3

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2
Q

recall the formula for: sulfuric acid, nitric acid, sodium hydroxide, potassium hydroxide, magnesium carbonate, sodium sulfate, potassium sulfate, magnesium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, barium sulfate, lead (II) nitrate, lead iodide, potassium iodide and potassium nitrate

A

H2SO4, HNO3, NaOH, KOH, MgCO3, Na2SO4, KSO4, MgSO4, BaSO4, Pb(NO3)2, PbI2, KI, KNO3

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3
Q

What is the relative atomic mass of an atom

A

The average mass of an atom of the element in comparison to the mass of 1/12th of a carbon 12 atom

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4
Q

Formula for moles

A

Number of moles = Mass/ molar mass

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5
Q

Cm3 to Dm3

A

Divide by 1000

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6
Q

Amount of moles =

A

Concentration X volume

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7
Q

1G of salt =

A

0.393g of sodium

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8
Q

Why should an acid based titration use a single indicator rather than a mixed imdicator

A

Because it gives a sudden colour change at the end point. Mixed indicator won’t give you the precise end point of a titration.

Mixed indicator = universal indicator
Single indicator= phenolphthalein (changes from pink to colourless)

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9
Q

How to measure the volume of gas

A

Use a gas syringe. Connect the syringe to the reaction container with the tube and as the reaction is carried out and gas is produced, gas will fill the syringe and push the plunger out. The graduations on the side show the volume of gas contained in the gas syringe.

Upturned measuring cylinder in a trough of water with connected tube. Air pressure will keep the water inside the cylinder. Delivery tube from the cylinder to the reaction container. As reaction occurs, gas fills the upturned cylinder snd pushes water out. Graduations on the side show the amount of gas collected. Same as upturned displacement (with an upturned burette). This is only accurate if the gas is not very soluble in water so not co2.

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10
Q

What happens at equilibrium

A

The rate of the forward reaction= the rate of the backwards reaction

Concentrations of products do not change.

The position of equilibrium is on the left is the concentration of reactions is greater than the concentration of products.

On the right of the concentration of products is greater than the concentration of reactants

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11
Q

How can a reversible reaction reach equilibrium

A

In a Closed system eg stopped flask or beaker. If the system is open the reacting substances may escape and equilibrium will not be reached.

Initially rate of forward reaction decreases, rate of backward reaction increases. Eventually they are the same

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12
Q
What does :
Removing a product
Adding a product
Removing a reactant
Adding a reactant
Increasing pressure
Increasing temperature
A

Removing product: moves to right
Adding product: moves to left
Removing reactant: moves to left
Adding reactant: moves to right
Increasing pressure: moved to the side with the least moles
Decreasing pressure: moved to side with more moles
Increasing temperature: favours the endothermic side of the reaction
Decreasing temperature: favours the exothermic side

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13
Q

Explain the contact process

A

Need : sulfur, air, oxygen

1: sulfur burned in air to make sulfur dioxide

S+ O2 –> SO2

2: sulfur dioxide burned with oxygen to make sulfur trioxide

2SO2 + O2 –> 2SO3

3: SO4 + H2O –> H2SO4

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14
Q

What conditions are needed for the contact process

A

V2O2 catalyst
Greater yield can be obtained by reducing the temperature because the forward reaction is exothermic
High enough temperature needed for a fast rate of reaction (450)

Atmospheric pressure used because it is to the right. High pressure would increase the yield but increasing the pressure would increase the cost and it wouldn’t be worth it because there is only a small increase in yield.

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15
Q

Acid ionises water to produce which ions

A

h+ ions

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16
Q

What is the difference between a strong acid and a weak acid

A

The ph of a weak acid is higher than a ph of a strong acid.

Acid strength is is a measure of the degree of ionisation of the acid. How much it ionises. Strong acids completely ionise in water. Weak acids partially ionise.

Weak acids form reversible reactions

17
Q

What is the concentration of an acid

A

It is a measure of the number of moles of acid in one dm3

18
Q

Why does ethanoic acid react slower than hydrochloric acid with the same concentration

A

Because ethanoic acid has a lower concentration of hydrogen io s. In ethanoic acid the hydrogen ions have a lower collision frequency with reactant particles.

19
Q

Explain why ethanoic acid is less conductive than hydrochloric acid of the same concentration

A

Because in weak acids there are less hydrogen ions so it is more difficult for a current to pass through.

20
Q

Why are precipitation reactions fast

A

The collision frequency between ions is large so there is a high chance that different ions will collide and cause a reaction.

Precipitates for, as soon as two suitable solutions are mixed together

21
Q

Barium chloride + sodium sulfate —>

A

Barium sulfate + sodium sulfate