Acids and Bases Test Flashcards
Complete the word equation for the reaction of Nitric acid and Lithium Hydroxide.
Nitric Acid + Lithium Hydroxide = ?
Nitric Acid + Lithium Hydroxide = lithium nitrate + hydrogen gas
Name the formula of: HCI
Hydrochloric acid
Name the formula of: Potassium Hydroxide
KOH
Name the formula of: Al2(CO3)3
Aluminium carbonate
Name the formula of: sulfuric acid
H2SO4
Name the formula of: NH3
Ammonia
Name the formula of: ethanoic acid
CH3COOH
Distinguish between an acid and a base: include the definition of an acid and base, a property of an acid and a property of a base
An acid is a substance that dissociates into H+ ions in solution while a base is a substance that can accept H+ ions from water. Properties of an acid include being sour and being reactive with metals. Properties of a base include being caustic and tasting bitter.
Sulfuric acid is a strong acid whereas ethanoic acid is a weak acid. In the laboratory, both can be found in bottles labelled “diluted” or “concentrated”. Distinguish between a strong and weak acid and distinguish between a concentrated and dilute acid.
A strong acid is an acid with a low pH measure, is fully ionised and dissociates into many hydrogen ions. A weak acid has a high pH measure, is only partially ionised and does not fully dissociate into hydrogen ions. A concentrated acid is a solution with a large number of acid particles in a given volume and a dilute acid is a solution with a low number of acid particles in a given volume.
A student collected a sample of rainwater from the side of a main road and found out it was acidic by using litmus paper and UI. Describe how the student could use red and blue litmus paper to do this test and explain the advantage of using UI over the litmus paper.
The student could prove it was an acidic substance by dipping the red and blue litmus paper into the rainwater sample. If the blue litmus paper stayed blue, it would either be neutral or basic, and it it turned red it would show that it was acidic. If you used the red litmus paper and it stayed red, it would either be neutral or acidic, and if the red litmus paper turned blue, it would show that the substance was acidic. The advantage of using UI over litmus paper would be that UI not only tells you if it is an acidic, neutral or basic substance, but it tells you the actual pH level of the substance. For instance if the substance was neutral, UI would turn green, if the substance was a strong acid it would turn red, and if it was a strong base, it would turn purple.
State the colour of UI for: rainwater (pH= 6)
green
State the colour of UI for: drain cleaner (pH= 13)
purple
State the colour of UI for: coke syrup (pH= 1)
red
You have 100 mL’s of Nitric acid mixed with UI. You decide to slowly add 200mLs of Lithium Hydroxide to it. The acid and base are the same strength and concentration. Discuss what happens during this process including the colour and pH of the solution after 100mLs of lithium hydroxide is added to 100mLs of acid, the change of of colour and pH as the lithium hydroxide is added SLOWLY and the colour and pH of the solution of the remaining 100mLs of lithium hydroxide is added (so 200 mLs of lithium hydroxide has now been added).
After 100 mLs of lithium hydroxide is added to 100mLs of nitric, the pH level will stay neutral as the reaction has been neutralised and therefore balanced, and the colour of the UI will be green. As the lithium hydroxide is added, the mixture will get more and more basic and will slowly go higher on the pH scale. The colour will go from green to a light blue, to dark blue as more and more hydroxide is added. As the last 100mLs of lithium hydroxide is added, the solution will now be basic and a dark purple colour.
Andy has just been fishing and his hands smell of fish. Discuss how lemon juice takes away the smell of the fish; include the name of this type of reaction, the general word equation for this reaction, explain what type of chemical the ‘fish smell’ and ‘lemon juice’ is and explain how lemon juice takes away the fish smell.
This reaction is a neutralisation. Fish is a base, and lemon is an acid. Acid + base = salt + water. Lemon juice is made of citric acid and the chemical that makes the fish smell is trimethylamine. The lemon juice gets rid of the fish smell because the acid in the citric acid (which is in the lemon juice) reacts with the amines (the reason for the odour) which are alkaline. When the amines react with the citric acid, ammonium salts are produced, meaning the citric acid neutralises the trimethylamine to make a salt, which takes away the fishy smell.
