Question

Please solve this paper of chemistry

Answer 1

Explanation:

Balanced reaction:

1) CH₄ + 2O₂ → CO₂ + 2H₂O

2) 3Mg + N₂ → Mg₃N₂

3) 2CO + O₂ → 2CO₂

4) Ca + 2H₂O → Ca(OH)₂ + H₂

5) 2H₂S + SO₂ → 2H₂O + 3S

6) 2NaCl + Pb(NO₃)₂ → PbCl₂ + 2NaNO₃

7) 2KlO₃ → 2KCl + 3O₂

8) CuSO₄ + 2NH₄OH → (NH₄)₂SO₄ + Cu(OH)₂

9) ZnCl₂ + Na₂CO₃ → ZnCO₃ + 2NaCl

10)  Already Balanced

Answer 2

Write the chemical formula of the compounds using criss-cross method :

So at first lets have some knowledge about Criss-cross method.

• What is a Criss-cross method ?

It's basically a method to find the correct chemical formula of compounds.

• Steps involved in Criss-cross method

» Step 1 :

⠀⠀⠀⠀ Write symbol for cation (left) then anion (right).

» Step 2 :

⠀⠀⠀⠀⠀ Write charge of the cation.

» Step 3 :

⠀⠀⠀⠀ Write charge of the anion.

» Step 4 :

⠀⠀⠀⠀ Check whether the charge is 0.

⠀⠀⠀If charge doesn't comes to be 0, criss-cross them

⠀⠀⠀i.e., $\sf\:cation^{superscript}$ = $\sf\:anion_{subscript}$

⠀⠀⠀⠀⠀ $\sf\:anion^{superscript}$ = $\sf\:cation_{subscript}$

Following all these steps we would end up getting the chemical formula of the compounds. So let's proceed with the given questions.

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i) Sodium bicarbonate - $\sf\:NaHCO_{3}$

ii) Lead (ll) sulphide - $\sf\:PbS$

iii) Chromium phosphate - $\sf\: CrPO_{4}$

iv) Magnesium sulphate - $\sf\:MgSO_{4}$

v) Ammonium carbonate - $\sf\:\left(NH_{4}\right)_{2}CO_{3}$

vi) Calcium nitride - $\sf\:Ca_{3}N_{2}$

vii) Aluminium Chloride - $\sf\:AlCl_{3}$

ix) Copper (ll) sulphite - $\sf\:CuSO_{4}$

x) Zinc nitrate - $\sf\:Zn\left(NO_{3}\right)_{2}$

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Balance the following equations :

Before jumping into the question let's first know the steps involved in balancing a chemical reaction.

» Step 1 :

⠀⠀⠀⠀ List all the elements present on each side i.e., the reactant and the product side.

» Step 2 :

⠀⠀⠀⠀ Observe how many atoms of each element are present ob each side.

Goal is to have same number of atoms of each element on both sides.

» Step 3 :

⠀⠀⠀⠀ Multiply the most propable coefficient on each side until each side has same number of atoms.

» Step 4 :

⠀⠀⠀⠀ Count and check the number of atoms of each element on either side to avoid any mistake.

Following all these steps we would end up balancing the chemical reactions. So let's proceed with the given questions. ‎

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1) $\sf\small\:CH_{4} + O_{2} \to CO_{2} + H_{2}O$

• $\sf\small\:CH_{4} + 2O_{2} \to CO_{2} + 2H_{2}O$

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2) $\sf\small\:Mg + N_{2} \to Mg_{3}N_{2}$

• $\sf\small\:3Mg + N_{2} \to Mg_{3}N_{2}$

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3) $\sf\small\:CO + O_{2} \to CO_{2}$

• $\sf\small\:2CO + O_{2} \to 2CO_{2}$

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4) $\sf\small\:Ca + H_{2}O \to Ca\left(OH\right) _{2} + H_{2}$

• $\sf\small\:Ca + 2H_{2}O \to Ca\left(OH\right) _{2} + H_{2}$

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5) $\sf\small\:H_{2}S + SO_{2} \to H_{2}O + S$

• $\sf\small\:2H_{2}S + SO_{2} \to 2H_{2}O + 3S$

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6) $\sf\small\:NaCl + Pb\left(NO_{3}\right) _{2} \to PbCl_{2} + NaNO_{3}$

• $\sf\small\:2NaCl + Pb\left(NO_{3}\right) _{2} \to PbCl_{2} + 2NaNO_{3}$

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7) $\sf\small\:KClO_{3} \to KCl + O_{2}$

• $\sf\small\:2KClO_{3} \to 2KCl + 3O_{2}$

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8) $\sf\small\small\:CuSO_{4} + NH_{4}OH \to \left(NH_{4}\right)_{2}SO_{4} + Cu\left(OH\right) _{2}$

• $\sf\small\:CuSO_{4} + 2NH_{4}OH \to \left(NH_{4}\right)_{2}SO_{4} + Cu\left(OH\right) _{2}$

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9) $\sf\small\:ZnCl_{2} + Na_{2}CO_{3} \to NaCl + ZnCO_{3}$

• $\sf\small\:ZnCl_{2} + Na_{2}CO_{3} \to 2NaCl + ZnCO_{3}$

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10) $\sf\small\:CaSO_{4} + K_{2}CO_{3} \to K_{2}SO_{4} + CaCO_{3}$

• The given reaction is already balanced.

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