Exothermic and Exodermic reactions

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What is an exothermic reaction? Give some examples (from reactions you have studied in class and in everyday life).
Exothermic reactions transfer energy to the surroundings. The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings become hotter. (Combustion, many oxidation reactions-rusting, Neutralisation-acid+alkalis)
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What is an endothermic reaction? Give some examples (from reactions you have studied in class and in everyday life).
These are reactions that take in energy from the surroundings. The energy is usually transferred as heat energy, causing the reaction mixture and surroundings to get colder. (Electrolysis and thermal decomposition of calcium carbonate)
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What is a reversible reaction? What symbol do you use in a word/symbol equation to represent this?
In a reversible reaction, the products can react to produce the original reactants again. we use two arrows, each with just half an arrowhead - the top one pointing right, and the bottom one pointing left.
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If a reaction is reversible and exothermic in one direction, what can you say about the reverse reaction and how do the energies of each compare?
If the forward reaction is exothermic, the reverse reaction is endothermic.
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What do the state symbols (s), (l), (g) and (aq) mean?
Solid, liquid, gas and aqueous (water)
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What does soluble mean?
(of a substance) able to be dissolved, especially in water.
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If a salt has been dissolved in a solute, how would you retrieve it?
Distillation- boil or evaporate water to leave salt
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What types of salts are made from a. Hydrochloric acid b. Sulphuric acid c. Nitric acid?
A. Hydrochloric acid- chlorides. B. Sulfuric acid- sulphates. C. Nitric acid- nitrates
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What is a base?
A substance that will neutralise an acid, but does not dissolve in water
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What is an alkali?
An alkali is any substance that produces OH- ions in water. (OH- ions are called hydroxide ions) An alkali has a pH of more than 7.
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What is a precipitate?
Precipitates can form when two soluble salts react in solution to form one or more insoluble products. The insoluble product separates from the liquid and is called a precipitate.
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If you add a metal to an acid, what would you expect to observe? How would you know when the reaction is finished?
Fizzing and hydrogen gas being released. It has finished when fizzing stops.
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Complete the word equation: Acid + metal →
Acid + metal → salt + hydrogen
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Complete the word equation: Acid + metal hydroxide →
Acid + metal hydroxide → salt + water
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What is the pH scale? What colour and number does it show for a strong acid? Strong alkali? Neutral solution?
The pH scale measures how acidic or alkaline a substance is. Substances with a pH of 7 are neutral, substances with a pH greater than 7 are alkaline (or 'basic') and substances with a pH lower than 7 are acidic. Red=acid, Black=alkaline
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What ion makes something acidic? What ion makes something alkaline? Write a symbol equation showing what happens when these ions react together.
Hydrogen ions make it acidic, while hydroxide ions make it alkaline. H+(aq) + OH–(aq) → H2O(l)
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If you were reacting an acid with an alkali, how would you know if the reaction was finished?
There would be water and salt, and te have soloution would be still
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If you were reacting an acid with an insoluble base, how would you know if the reaction had finished?
They dissolve (mostly) and the solutio would be still
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What is a neutralisation reaction? (what is always made?)
When an alkali is added to an acid the pH of the mixture rises. This is because the alkali reacts with the acid to form neutral products (Salt and water are created).
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What happens when ammonia dissolves in water?
Ammonia acts as the base and water acts as the acid. This results in an ammonium ion and a hydroxide ion. The ammonium ion is the conjugate acid and OH- is the conjugate base. The hydroxide ion means that the solutions would be greater than 7.
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What type of salts does ammonia produce? What are these salts used for?
Ammonium salts such as: Ammonium nitrate; Ammonium sulphate and Ammonium Phosphate are typically used as fertilisers.
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Other cards in this set

Card 2

Front

What is an endothermic reaction? Give some examples (from reactions you have studied in class and in everyday life).

Back

These are reactions that take in energy from the surroundings. The energy is usually transferred as heat energy, causing the reaction mixture and surroundings to get colder. (Electrolysis and thermal decomposition of calcium carbonate)

Card 3

Front

What is a reversible reaction? What symbol do you use in a word/symbol equation to represent this?

Back

Preview of the front of card 3

Card 4

Front

If a reaction is reversible and exothermic in one direction, what can you say about the reverse reaction and how do the energies of each compare?

Back

Preview of the front of card 4

Card 5

Front

What do the state symbols (s), (l), (g) and (aq) mean?

Back

Preview of the front of card 5
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