Difference between revisions of "Conservation of Mass"

Latest revision as of 16:28, 13 December 2019

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.


Mass_solvent + Mass_solute = Mass_solution

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.

Conservation of mass can be observed in closed systems in which none of the products can escape and no other chemicals enter the system.

In an open system any chemical reaction which produces a gas will appear to decrease in mass but only because the mass has moved to a different location. The particles of gas escape the container.

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.

M_Reactants = M_Products

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
Find the Relative Formula Mass of the reactants. M_r of Mg = 24g M_r of O₂ = 16x2 M_r of O₂ = 32g	Find the Relative Formula Mass of the reactants. M_r of CH₄ = 16g M_r of O₂ = 16x2 M_r of O₂ = 32g	Find the Relative Formula Mass of the reactants. M_r of NaOH = 40g M_r of HCl = 36.5g
State the ratio of moles of each chemical needed. 2 moles of Mg are needed for every 1 mole of O₂	State the ratio of moles of each chemical needed. 1 mole of CH₄ is needed for every 2 moles of O₂	State the ratio of moles of each chemical needed. 1 mole of HCl are needed for every 1 mole of NaOH
Find the number of moles supplied of the known mass. No. Moles = \(\frac{Mass}{M_r}\) No. Moles = \(\frac{48}{24}\) No. Moles = 2 Mole Therefore 1 mole of O₂ is needed. 1 mole of O₂ = 32g	Find the number of moles supplied of the known mass. No. Moles = \(\frac{Mass}{M_r}\) No. Moles = \(\frac{32}{16}\) No. Moles = 2 Mole Therefore 4 moles of O₂ are needed. 4 moles of O₂ = 128g	Find the number of moles supplied of the known mass. No. Moles = \(\frac{Mass}{M_r}\) No. Moles = \(\frac{20}{40}\) No. Moles = 0.5 Mole Therefore 0.5 mole of HCl is needed. 0.5 mole of HCl = 18.25g

Beyond the Curriculum

References

@@ Line 36: / Line 36: @@
 ===About Conservation of Mass===
 : In a [[Chemical Reaction|chemical reaction]] law of '''conservation of mass''' indicates that the total [[mass]] of the [[product]]s is the same as the total [[mass]] of the [[reactant]]s.
+: '''Conservation of mass''' can be [[observed]] in [[Closed System|closed system]]s in which none of the [[product]]s can escape and no other [[chemical]]s enter the [[system]].
+: In an [[Open System|open system]] any [[Chemical Reaction|chemical reaction]] which [[product|produces]] a [[gas]] will appear to decrease in [[mass]] but only because the [[mass]] has moved to a different location. The [[particle]]s of [[gas]] escape the container.
 ===Examples===
@@ Line 52: / Line 54: @@
 ===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 [[product]]s = the total [[mass]] of [[reactant]]s.
+M<sub>Reactants</sub> = M<sub>Products</sub>
 {| class="wikitable"
 | style="height:20px; width:200px; text-align:center;" |
@@ Line 91: / Line 95: @@
 x = 146g
+|}
+===Calculating the Mass Required for a Complete Reaction===
+{| class="wikitable"
+| style="height:20px; width:200px; text-align:center;" |
+Find the [[mass]] of [[Oxygen]] needed to completely [[oxidise]] all of the [[Magnesium]]:
+Mg + O<sub>2</sub> → 2MgO
+g + x = y
+| style="height:20px; width:200px; text-align:center;" |
+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>
+g + x = y
+| style="height:20px; width:200px; text-align:center;" |
+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
+g + x = y + z
+|-
+| style="height:20px; width:200px; text-align:center;" |
+Find the [[Relative Formula Mass]] of the [[reactant]]s.
+M<sub>r</sub> of Mg = 24g
+M<sub>r</sub> of O<sub>2</sub> = 16x2
+M<sub>r</sub> of O<sub>2</sub> = 32g
+| style="height:20px; width:200px; text-align:center;" |
+Find the [[Relative Formula Mass]] of the [[reactant]]s.
+M<sub>r</sub> of CH<sub>4</sub> = 16g
+M<sub>r</sub> of O<sub>2</sub> = 16x2
+M<sub>r</sub> of O<sub>2</sub> = 32g
+| style="height:20px; width:200px; text-align:center;" |
+Find the [[Relative Formula Mass]] of the [[reactant]]s.
+M<sub>r</sub> of NaOH = 40g
+M<sub>r</sub> of HCl = 36.5g
+|-
+| style="height:20px; width:200px; text-align:center;" |
+State the [[ratio]] of [[mole]]s of each [[chemical]] needed.
+[[mole]]s of Mg are needed for every 1 [[mole]] of O<sub>2</sub>
+| style="height:20px; width:200px; text-align:center;" |
+State the [[ratio]] of [[mole]]s of each [[chemical]] needed.
+[[mole]] of CH<sub>4</sub> is needed for every 2 [[mole]]s of O<sub>2</sub>
+| style="height:20px; width:200px; text-align:center;" |
+State the [[ratio]] of [[mole]]s of each [[chemical]] needed.
+[[mole]] of HCl are needed for every 1 [[mole]] of NaOH
+|-
+| style="height:20px; width:200px; text-align:center;" |
+Find the number of [[mole]]s supplied of the known [[mass]].
+No. [[Mole]]s = <math>\frac{Mass}{M_r}</math>
+No. [[Mole]]s = <math>\frac{48}{24}</math>
+No. [[Mole]]s = 2 Mole
+Therefore 1 [[mole]] of O<sub>2</sub> is needed.
+[[mole]] of O<sub>2</sub> = 32g
+| style="height:20px; width:200px; text-align:center;" |
+Find the number of [[mole]]s supplied of the known [[mass]].
+No. [[Mole]]s = <math>\frac{Mass}{M_r}</math>
+No. [[Mole]]s = <math>\frac{32}{16}</math>
+No. [[Mole]]s = 2 Mole
+Therefore 4 [[mole]]s of O<sub>2</sub> are needed.
+[[mole]]s of O<sub>2</sub> = 128g
+| style="height:20px; width:200px; text-align:center;" |
+Find the number of [[mole]]s supplied of the known [[mass]].
+No. [[Mole]]s = <math>\frac{Mass}{M_r}</math>
+No. [[Mole]]s = <math>\frac{20}{40}</math>
+No. [[Mole]]s = 0.5 Mole
+Therefore 0.5 [[mole]] of HCl is needed.
+.5 [[mole]] of HCl = 18.25g
 |}
+==Beyond the Curriculum==
+{{#ev:youtube|https://www.youtube.com/watch?v=2S6e11NBwiw}}
+===References===
+====AQA====
+:[https://www.amazon.co.uk/gp/product/1471851354/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851354&linkCode=as2&tag=nrjc-21&linkId=9012a0d354024419214fb3ad5ac44ba0 ''Conservation of mass, page 181, GCSE Combined Science Trilogy 1, Hodder, AQA '']
+:[https://www.amazon.co.uk/gp/product/1782945571/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945571&linkCode=as2&tag=nrjc-21&linkId=9e29fad914244909903e5e93f8a01d91 ''Conservation of mass, page 43, GCSE Chemistry; The Revision Guide, CGP, AQA '']
+:[https://www.amazon.co.uk/gp/product/0198359381/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359381&linkCode=as2&tag=nrjc-21&linkId=47c8d1ae58d8b3a5e2094cd447154558 ''Conservation of mass, page 6, GCSE Chemistry; Third Edition, Oxford University Press, AQA '']
+:[https://www.amazon.co.uk/gp/product/1471851346/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1471851346&linkCode=as2&tag=nrjc-21&linkId=3ac654f4b0da781c49c855a1af4c92ea ''Conservation of mass, page 68, GCSE Chemistry, Hodder, AQA '']
+:[https://www.amazon.co.uk/gp/product/019835939X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=019835939X&linkCode=as2&tag=nrjc-21&linkId=57e96876985fc39b1a3d8a3e3dc238b6 ''Conservation of mass, page 78, GCSE Physics; Third Edition, Oxford University Press, AQA '']
+:[https://www.amazon.co.uk/gp/product/178294639X/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=178294639X&linkCode=as2&tag=nrjc-21&linkId=51599bb45a2bfaf7c1b6a978b2ca2616 ''Conservation of mass, pages 108-110, GCSE Combined Science Trilogy; Chemistry, CGP, AQA '']
+:[https://www.amazon.co.uk/gp/product/1782945962/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945962&linkCode=as2&tag=nrjc-21&linkId=476bb5c8d1dfb5c08ac81b6d4d1c98d8 ''Conservation of mass, pages 114- 116, GCSE Chemistry, CGP, AQA '']
+:[https://www.amazon.co.uk/gp/product/1782945598/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945598&linkCode=as2&tag=nrjc-21&linkId=ad276ad49df77ab4b40ab4fd0fe09801 ''Conservation of mass, pages 124, 125, 195, GCSE Combined Science; The Revision Guide, CGP, AQA '']
+:[https://www.amazon.co.uk/gp/product/0008158770/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0008158770&linkCode=as2&tag=nrjc-21&linkId=ec31595e720e1529e49876c3866fff6e ''Conservation; of mass, pages 88, 116-17, GCSE Physics; Student Book, Collins, AQA '']
+====Edexcel====
+:[https://www.amazon.co.uk/gp/product/1782945725/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945725&linkCode=as2&tag=nrjc-21&linkId=694be7494de75af3349537d34e13f7f0 ''Conservation of mass, apge 26, GCSE Chemistry; The Revision Guide, CGP, Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1292120193/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120193&linkCode=as2&tag=nrjc-21&linkId=572df39392fb4200db8391d98ae6314e ''Conservation of mass, law of, pages 218-219, GCSE Combined Science, Pearson Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1292120215/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120215&linkCode=as2&tag=nrjc-21&linkId=8f96ddb76196848bafdb124354e4cf77 ''Conservation of mass, law of, pages 74-75, GCSE Chemistry, Pearson, Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1782945741/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945741&linkCode=as2&tag=nrjc-21&linkId=30da4f2178da182547b62a7329d13b57 ''Conservation of mass, page 89, GCSE Combined Science; The Revision Guide, CGP, Edexcel '']
+:[https://www.amazon.co.uk/gp/product/1782948147/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782948147&linkCode=as2&tag=nrjc-21&linkId=f63dcd8345f4e49c717b39a228a36c7c ''Conservation of mass, pages 74-76, GCSE Chemistry, CGP, Edexcel  '']
+:[https://www.amazon.co.uk/gp/product/1292120215/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1292120215&linkCode=as2&tag=nrjc-21&linkId=8f96ddb76196848bafdb124354e4cf77 ''Mass conservation, pages 74-75, GCSE Chemistry, Pearson, Edexcel '']
+====OCR====
+:[https://www.amazon.co.uk/gp/product/1782945695/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945695&linkCode=as2&tag=nrjc-21&linkId=ceafcc80bcad6b6754ee97a0c7ceea53 ''Conservation of mass, page 107, Gateway GCSE Combined Science; The Revision Guide, CGP, OCR  '']
+:[https://www.amazon.co.uk/gp/product/1782945679/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=1782945679&linkCode=as2&tag=nrjc-21&linkId=a2db42f7b4bdf10cafaafa3bb9120940 ''Conservation of mass, page 34, GCSE Chemistry; The Revision Guide, CGP, OCR Gateway '']
+:[https://www.amazon.co.uk/gp/product/0198359829/ref=as_li_tl?ie=UTF8&camp=1634&creative=6738&creativeASIN=0198359829&linkCode=as2&tag=nrjc-21&linkId=90e8d7b4f039d53035238fa0320fe00b ''Law of conservation of mass, pages 90-91, Gateway GCSE Chemistry, Oxford, OCR '']

Difference between revisions of "Conservation of Mass"

Latest revision as of 16:28, 13 December 2019

Contents

Key Stage 3

Meaning

About Conservation of Mass

Key Stage 4

Meaning

About Conservation of Mass

Examples

Calculating the Mass of a missing Product/Reactant

Calculating the Mass Required for a Complete Reaction

Beyond the Curriculum

References

AQA

Edexcel

OCR