Difference between revisions of "Conservation of Mass"
(→Calculating the Mass Required for a Complete Reaction) |
(→Calculating the Mass Required for a Complete Reaction) |
||
| Line 102: | Line 102: | ||
2Mg + O<sub>2</sub> → 2MgO | 2Mg + O<sub>2</sub> → 2MgO | ||
| − | 48g + x = | + | 48g + x = y |
| style="height:20px; width:200px; text-align:center;" | | | style="height:20px; width:200px; text-align:center;" | | ||
| − | Find the [[mass]] of [[ | + | Find the [[mass]] of [[Oxygen]] needed for the [[Complete Combustion|complete combustion]] of [[Methane]]. |
CH<sub>4</sub> + 2O<sub>2</sub> → 2H<sub>2</sub>O + CO<sub>2</sub> | CH<sub>4</sub> + 2O<sub>2</sub> → 2H<sub>2</sub>O + CO<sub>2</sub> | ||
| − | + | 32g + x = y | |
| style="height:20px; width:200px; text-align:center;" | | | style="height:20px; width:200px; text-align:center;" | | ||
| − | Find the [[mass]] of [[Hydrochloric Acid]] needed | + | Find the [[mass]] of [[Hydrochloric Acid]] needed to completely [[Neutralise (Chemistry)|neutralise]] all of the [[Sodium Hydroxide]]. |
NaOH + HCl → NaCl + H<sub>2</sub>O | NaOH + HCl → NaCl + H<sub>2</sub>O | ||
| − | + | 20g + x = y + z | |
|- | |- | ||
| style="height:20px; width:200px; text-align:center;" | | | style="height:20px; width:200px; text-align:center;" | | ||
Revision as of 13:06, 3 January 2019
Contents
Key Stage 3
Meaning
Conservation of Mass is a law of the universe that states that mass cannot be created or destroyed, it can only be moved from one place to another.
About Conservation of Mass
- In dissolving conservation of mass means that the mass of the solvent and the mass of the solute can be added to find the mass of the solution.
 |
| Masssolvent + Masssolute = Masssolution |
- In a chemical reaction conservation of mass means that the same atoms which made up the reactants must make up the products. So the atoms are not created or destroyed in a chemical reaction, they are just rearranged.
 |
|
Conservation of mass tells us that if there are 4 Hydrogen atoms and 2 Oxygen atoms at the start of this reaction then there will be the end of the reaction 4 Hydrogen atoms and 2 Oxygen atoms at the end of the reaction. |
 |
|
In this reaction you can see that mass is conserved because there are 4 Hydrogen atoms, 4 Oxygen atoms and 1 Carbon atom in the reactants and all the same atoms are found in the products. |
Key Stage 4
Meaning
Conservation of Mass is a law of the universe that states that mass cannot be created or destroyed, it can only be moved from one place to another.
About Conservation of Mass
- In a chemical reaction law of conservation of mass indicates that the total mass of the products is the same as the total mass of the reactants.
Examples
Methane + Oxygen → Water + Carbon Dioxide
CH4 + 2O2 → 2H2O + CO2
16g + 64g = 36g + 44g
Sodium Hydroxide + Hydrochloric Acid → Sodium Chloride + Water
NaOH + HCl → NaCl + H2O
40g + 36.5g = 58.5 + 18g
Calculating the Mass of a missing Product/Reactant
- The mass of a missing product of reactant can be found because the total mass of the products = the total mass of reactants.
MReactants = MProducts
|
Find the mass of Calcium Oxide produced in the following reaction: CaCO3 → CaO + CO2 25g = x + 11g |
Find the mass of Carbon Dioxide produced in the following reaction: CH4 + 2O2 → 2H2O + CO2 4g + 16g = 9g + x |
Find the mass of Hydrochloric Acid needed in the following reaction: NaOH + HCl → NaCl + H2O 160g + x = 234g + 72g |
|
x = 25g - 11g x = 14g |
20g = 9g + x x = 20g - 9g x = 11g |
160g + x = 306g x = 306g - 160g x = 146g |
Calculating the Mass Required for a Complete Reaction
|
Find the mass of Oxygen needed to completely oxidise all of the Magnesium: 2Mg + O2 → 2MgO 48g + x = y |
Find the mass of Oxygen needed for the complete combustion of Methane. CH4 + 2O2 → 2H2O + CO2 32g + x = y |
Find the mass of Hydrochloric Acid needed to completely neutralise all of the Sodium Hydroxide. NaOH + HCl → NaCl + H2O 20g + x = y + z |
|
x = 25g - 11g x = 14g |
20g = 9g + x x = 20g - 9g x = 11g |
160g + x = 306g x = 306g - 160g x = 146g |