# The nature of substances and chemical reactions - chemical eqautions and chemical calculations

How do you write a balanced symbol equation?
Stage 1 - Identify the reactants and products in the question. Stage 2 - write out the word equation for the reaction. Stage 3 - Use the periodic table to write the symbols for the elements in the reaction.
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Continued from Q1
Stage 4 - use the ions table to work out the formula for any compound in the reaction. Stage 5 - Replace the words in the equations with the symbols or formula. Stage 6 - Balance the equation. Step 7 - add the state symbols
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What is the formula for Hydrocholric acid ?
HCl
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What is the formula for Sulfuric acid (remember the rhyme)
H2SO4 (Our Johnny passed away today, his face we'll see no more, what Johnny thought was H2O, was H2SO4)
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What is the formula for nitric acid ?
HNO3
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What is the formula for sodium hydroxide ?
NaOH
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What is the formulas for carbon dioxide and sulfur dioxide ?
CO2, SO2
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What is the formulas for oxygen, hydrogen, chlorine and ammonia ?
O2, H2, Cl2, NH3
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What is the formula for Methane ?
CH4
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What are the diatomic elements ? (remember the rhyme)
H, N, F, O, I, Cl, Br. (Have No Fear Of Ice CoLd BeeR)
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How do you find the Molar masses?
Ar - Top number on the element of the periodic table
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How do you find the number of moles ?
No moles = Mass (g) / Mr
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How do you find the Mass in Grams ?
Mass (g) = No moles x Mr
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How do you find he Mr ?
Mr = Mass (g) / No moles
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What is avogadro's number ?
6x10 to the 23
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How do you calculate the number of MOLECULES of element/compound in a certain amount of substance ?
Molecules = M / Mr or Atom = M / ar
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Calculating the formulas of compound - (Impiriacal formula)How do you do this ?
Stage 1 - List ALL the elements in the compound and the mass of each element. Stage 2 - Use the RELATIVE ATOMIC MASS numbers to work out how many atoms of each element there are for the given masses (No of atoms of certain element = Mass of element
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Continuation of card 17
divided by the Ar of the element) Stage 3 - Using the number of atoms of each element calculated in stage 2, determine the simplest ration and form the simplest formula.
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How do you calculate the reacting masses of reactants and products ?
Theory actual method. Stage 1 - Identify what parts you need to have and cross out the bits that you don't need. Stage 2 - Work out the Mr of the relevant formulas. Stage 3 - Using what you already know find a relationship between the theoretical
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Continuation of card 19
Massses and the actual mass produced. then when you know the relationship, repeate for the unknown formula
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How do you calculate percentage Yeild ?
Percentage yield = Actual yield / theoretical yield x 100.
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Find the Molar mass of CaS and Fe2O3 ?
See page 7 of booklet
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Calculate the number of moles of Calcium Sulfide (CaS) in 3.6Kg ?
See page 9 of booklet
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Calculate the mass of 0.1 moles of Calcium Carbonate (CaCO3)
See page 11 of booklet
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Calculate the number of molecules in 32g of Methane, CH4 ?
See page 12 of booklet
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Calculate the number of molecules of calcium sulfide in 7.2g ?
See page 13 of booklet
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Calculate the number of atoms of sulfur in 32g ?
See page 13 of booklet
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25.4g of iron chloride was found to contain 11.2g of iron Calculate the simplest formula for this chloride of iron. show workings
See page 14
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The equation for the extraction of iron from its ore inside the furnace is given below : Fe2O3 + 3CO -------> 2Fe +3CO2. How much iron will be produced from 320 tonnes of the iron ore?
see page 16 of booklet
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Using your answer to part 1 on card 29, calculate the percentage by mass of iron in iron ore .
work it out.
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The nature of substances and chemical reactions - chemical eqautions and chemical calculations
Year 9/10
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## Other cards in this set

### Card 2

#### Front

Stage 4 - use the ions table to work out the formula for any compound in the reaction. Stage 5 - Replace the words in the equations with the symbols or formula. Stage 6 - Balance the equation. Step 7 - add the state symbols

#### Back

Continued from Q1

HCl

### Card 4

#### Front

H2SO4 (Our Johnny passed away today, his face we'll see no more, what Johnny thought was H2O, was H2SO4)

HNO3