acids and bases and salt preperations

Question 1

what is an acid

Answer 1

An acid contains hydrogen, and releases hydrogen ions in reactions

Question 2

what is a salt

Answer 2

Salt = a compound when a metal replaces the hydrogen in an acid

Question 3

what is HNO3

Answer 3

HNO3 = nitric acid

Question 4

what is ammonia chemical formula

Answer 4

NH3 = ammonia

Question 5

chemical formula for phosphoric acid

Answer 5

H3PO4 = phosphoric acid

Question 6

chemical formula for ethanoic acid

Answer 6

CH3COOH = ethanoic acid

Question 7

what happens when a hydrogen is replaced by an ammonium molecule

Answer 7

When the hydrogen is replaced by an ammonium molecule instead of a metal, it becomes an ammonium salt

Question 8

chemical formula for ammonium

Answer 8

Ammonium = NH4+

Question 9

list all general equations (6)

Answer 9

acid+base –> salt +water
acid +metal –> salt + H2
acid + metal oxide –> salt + H2O
acid + metal hydroxide –> salt + H2O
acid + metal carbonate –> salt + CO2 + H2O
acid + ammonia–> ammonium salt + water

Question 10

what is effervescence

Answer 10

When gas a produced in a chemical reaction, it is called effervescence

Question 11

How can you confirm that the gas produced in this reaction is hydrogen?

Answer 11

–> squeaky pop test –> put a lighted splint in the gas - if it creates a squeaky pop sound that gas is hydrogen

Question 12

why are magnesium with acid reaction faster than zinc with acid

Answer 12

In comparison to the acid reactions with magnesium, the acid reactions with zinc are slower as zinc is lower down the reactivity series in comparison with magnesium

Question 13

what is a base

Answer 13

Base - something that neutralises an acid
Alkalis are soluble in water, some bases are not.

Question 14

what colour change happens between copper II oxide and dilute h2so4

Answer 14

Copper (II) Oxide (black powder) reacts with hot dilute sulfuric acid
This creates a copper sulfate solution which is BLUE

Question 15

all copper solutions are what colour

Answer 15

ALL copper solutions = blue/blue-green solution

Question 16

are nitrates soluble

Answer 16

All nitrates are soluble

Question 17

what are the only chlorides that are insoluble

Answer 17

Lead and silver are the only chlorides that are insoluble (L and S both in chLorideS)

Question 18

which lead compounds are soluble

Answer 18

Other than nitrate, anything lead is insoluble

Question 19

are carbonates soluble

Answer 19

All carbonates are insoluble

Question 20

are hydroxides soluble

Answer 20

Most hydroxides are insoluble (calcium is partially)
EXCEPTION TO ALL THE ABOVE IS ammonium, potassium and sodium (APS) is ALWAYS soluble

Question 21

what can you only mix with cold acids to make salts

Answer 21

When making salts, it is only carbonates and magnesium that you can mix cold acids

Question 22

what do u add in excess when making magnesium sulfate

Answer 22

When making magnesium sulfate, you add magnesium in excess until it stops reacting

Question 23

when making salts, what 3 metals cant u add in excess and why

Answer 23

You can’t do this with APS (ammonium, potassium and sodium)
Magnesium is not soluble in water - SO, when you add it to aqueous acid, it only reacts with the acid - hence when all the acid has been reacted with, you see the excess magnesium
HOWEVER, with APS, as they are soluble in water, when you add them to aqueous acid, they react with the acid, HOWEVER, they ALSO dissolve in the water - SO you can’t add just enough metal to neutralise the acid
SO, you mix a solution of the metal with a solution of the acid

Question 24

how do u figure out how much u need to neutralise

Answer 24

To figure out how much of each solution is needed for complete neutralisation, we use titration

Question 25

when making sodium sulfate crystals, what indicator do u use

Answer 25

When making sodium sulfate crystals we use methyl orange - red in acidic solutions and yellow in alkaline solutions - orange is neutral

Question 26

why is copper sulfate blue rather than white

Answer 26

Copper sulfate solution is blue as it contains hydrous copper sulfate

Question 27

why should u use crystallisation instead of evaporation to obtain blue crystals

Answer 27

In the process of obtaining these blue crystals, you must use crystallisation instead of evaporation as if you let all the water evaporate off, it forms anhydrous copper sulfate which is white

Question 28

what is the symbol equation for hydrous copper sulfate

Answer 28

The symbol symbol of this is: CuSO4 (aq) + 5H2O(l) --> CuSO4.H2O(s) (got goes in the middle not the bottom) Crystalisation reaction for magnesium sulfate:

Question 29

tell me about ammonium crystals

Answer 29

Ammonium sulfate crystals: NH3 + H2SO4 --> (NH4)2SO4 Unlike the metal crystals, ammonium sulfate crystals don’t undergo water of crystallisation To make insoluble salts, you mix two soluble solutions together For silver chloride (an insoluble salt), you mix silver nitrate and sodium chloride This is a precipitation precipitate = a solid formed from a chemical reaction that has liquids or gases In this reaction, the silver chloride is the precipitate

Question 30

equation to make silver cchloride

Answer 30

AgNO3(aq)+NaCl(aq-->AqCl(s)+NANO3(aq)

Question 31

why is silver chloride a precipitate

Answer 31

Ionic compounds dissociate in water (separate). SO, when you mix two aqueous solutions, sometimes a precipitate can form The attraction between silver ions and chloride ions is so strong that the ions stick together even in water, forming a precipitate

Question 32

what is an example of precipitation reaction

Answer 32

For silver chloride (an insoluble salt), you mix silver nitrate and sodium chloride This is a precipitation, In this reaction, the silver chloride is the precipitate

Question 33

define a precipitate

Answer 33

precipitate = a solid formed from a chemical reaction that has liquids or gases

Question 34

What is the process of making salts when part ofthe salt is ammonium, potassium or sodium salts?

Answer 34

you mix a metal + an acid add the metal to the acid until you see unreacted metal residue filter ou any unreacted metal heat the solution slowly and the leave to dr

Question 35

What is the process of making salts when it is NOT an ammonium, potassium, or sodium salt?

Answer 35

mix and acid with an alkali add an indicator to monitor when the solution has neutralised when it has neturalised you then heat the solution until the crystals form and are then left to dry

Question 36

whats the equation to make barium sulfate

Answer 36

Ba(NO3)2+K2SO4--->BaSO4 + 2KN03

Question 37

what is arhnius theory

Answer 37

Arrhenius theory = acid produces H+ in solution and alkali produces OH- in solution

Question 38

what is bronsted-lowry theory

Answer 38

Bronsted-Lowry Theory: an acid is a proton donor

Question 39

what is an alkali

Answer 39

Proton = H+ ion an alkali is a proton doner H2O + HCl --> H3O+ (aq) + Cl-