Types Of Chemical Reactions Flashcards by M A

What is a neutralisation reaction

Tje reaction between an acid and a base that produces a neutral solution

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What is an acid

A substance, that when dissolved in water, releases H+ ions

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What is the deifference between a base and alkali

A base is a substance that neutralises an acid, whereas alkalis are also able to neutralise acids, but release OH- ions when dissolved in water

Alkali - release OH- ions in water when dissolved
Base - neutralise acid

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What is an alkali

A substance, that when dissolved in water realises OH- ions

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What is produced when an acid reacts with a base

Produced a SALT + WATER

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What happens when an acid reacts with a metal

Produces SALT + hydrogen

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What happens when an acid reacts with a metal carbonate

produces SALT + WATER + CO2

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How to find what salt is created?

First element of alkali plus last element of acid

hydroCHLORIC acid + SODIUM hydroxide —> SODIUM CHLORIDE

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Why is universal indicator not used as indicator

Universal indicator shows gradual color changes through a range of colours which making it hard to detect precise endpoints.

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What is the shape of a pH graph curve

A mirrored S shape

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What is the definition of a concentrated acid

It is a substance which has a high ratio of acid to volume of solution

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What is the definition of a dilute acid

An substance which has a low ratio of acid to volume of solute

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How do you change how can concentrated an acid is

By changing the volume of water it is dissolved in. More water means that it is less concentrated and vies versa

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What is the definition of a strong acid

A strong acid is an acid which fully dissociates in water
— (all of the molecules get split up into their ions)

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What is the definition of a weak acid

An acid which only partially dissociates in water
—(only some particles split into ions)

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What can weak acids do

Weak acids are reversible, meaning that they can split and join back together

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What is pH

pH is the measure of the concentration of H+ ions in a solution

What does it mean by a weak, concentrated acid

-> almost all particles are bonded tightened
-> BUT there are a lot of them, meaning that they can be corrosive

What does it by mean by weak, dilute acid

-> very few particles are dissociated
-> and there is a low ratio acid particles to volume of solute

What is the meaning of strong, concentrated acid

-> all of the moleucles are dissociated
-> there are a lot of these ions present
most corrosive

What does it mean by strong, dilute acid

-> all molecules are dissociated
-> BUT, there are not that many of them, meaning it is not as dangerous

What is the process of oxidation in terms of oxygen

Gain of oxygen

What happens to the pH when a metal is added to a sample of acid

The pH will be below 7, and the magnesium will fizz

What happens when metal is added to a sample of an alkali

-> the pH remains above 7
-> no reaction with magnesium

What happens to the pH when a metal carbonate is added to an acid

The pH increases a lot more than with just a metal, which increases very slightly

Why is it different when a metal and metal carbonate are dissolved in water

In a metal carbonate, the H+ ions react to form H20, making it have a much higher pH. In just the metal, the H+ ions only reduce to form H2 atoms, meaning it only increases slightly

The reaction of methane and oxygen produces heat. Explain why (3 marks)

The bonds breaking is endothermic The bonds being made is exothermic More energy is given out than taken in meaning that the reaction is exothermic

What does a reducing agent do in terms of electrons

It donates electrons to the +ve ions

What is a piece of equipment that a student could use to test the pH of a substance

pH probe

How to use a pH probe

- wash the probe - put it in the solution

The student concluded that the higher the reactivity, the higher the temp rise. How could she check this

-> use different masses -> range of metals

What is reduction in terms of OXYGEN

it is the LOSS of oxygen ##footnote Oxygen is removed from the oxidising agent and given to the reducing agent

Describe the relationship between the number of carbon atoms in the molecule and it’s boiling point

-> as the molecules increase, so does the boing point ->because of the greater intermolecular forces between them

How to make a dry sample of a salt

-> have an excess of the base/alkali -> whilst reacting, heat them -> filter excess base/alkali used from the solution -> evaporate most of the water from the solution of water and Salt -> leave it to dry in an oven

How can you tell in titration when the alkali is just neutralised

-> One drop makes the colour change -> goes from blue to red

What does a white precipitate mean

That the product has an ion in it, most commonly. Sulfate, chlorine, carbonate, nitrate

Which ions from precipitates

Sulfate ions + barium Chlorine ions + silver

Describe how a sample of solid ammonium sulfate is prepared in a laboratory. Explain why this method is not suitable to be used industrially.

-> titre ammonia against sulphuric acid to get exact amounts to have them fully react -> add the correct volumes without and indicator solution -> slowly evaporate the solution over a hot bath -> the reason it is not industrially used is that it is very hard to steam it at a large scale

What to do when describing a neutralisation reaction

Write the names of the products and the names of the reactants

What apparatus is used to measure volume of gas produced in a reaction

-> gas syringe -> beaker / flask

What is on the end of every alkali and what is on the end of every acid

alkali = hydroxide Acid = Always has H at the beginning of chemical formula

Write the ionic equation for neutralisation

(H+) + (OH-) —> H2O