Chemical Reactions and Equations: Class 10 Chemistry Q&A · Page 6
120 free answers on Chemical Reactions and Equations (Chemistry) for Class 10 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ChemistryClass 10ICSE
What are the various ways in which a chemical equation can be made more informative? Give examples to illustrate your answer. (b) Write balanced chemical equation from the following information: An aqueous calcium hydroxide solution (lime water) reacts with carbon dioxide gas to produce a solid calcium carbonate precipitate and water.
(a) Ca(OH)2 (aq)+ CO2 (g)---3000°C →CaCO3(s)+H2O(l) A chemical equation can be informative by 1) The chemical states is indicated by (s) for solids, (l) for liquids and (g) for gases and (aq) for aqueous solution 2) Temperature written on the above of arrow 3) Arrow upwards shows compound or any gas formed escaped or liberated 4) Arrow downwards shows precipitated 5) Heat is written on reactant side to indicate exothermic and when on written product side it will be endothermic b) Ca(
- ChemistryClass 10ICSE
When hydrogen is passed over copper oxide, copper and steam are formed. Write a balanced equation for this reaction and state which of the chemicals are: (i) Elements (ii) Compounds (iii) Reactants (iv) Products (v) Metals Non-metals
Solutions: H2 + CuO→ Cu + H2O Elements : H2 and Cu Compounds : CuO and H2O Reactants: H2 and CuO Products: Cu and H2O Metal: Cu Non-metal: H2
- ChemistryClass 10ICSE
What is a chemical equation? Explain with the help of an example. (b) Giving examples, state the difference between balanced and unbalanced chemical equations. (c) Balance the following chemical equations: (i) NH3 → N2 + H2 (ii) C +CO2→ CO
(a) Solutions: Chemical equations are the symbolic representation of chemical reactions in which the reactants and products are expressed in terms of chemical formulae. Reactant entities are given on the left side and product entities are given on the right side of a chemical equation Example: Zn + H2SO4→ZnSO4 + H2 A balanced chemical equation is always energy and mass conservative whereas un
- ChemistryClass 10ICSE
(a) Give one example of a chemical reaction. (b) State two characteristics of the chemical reaction which takes place when dilute sulphuric acid is poured over zinc granules. (c) Give two characteristics of the chemical reaction which occurs on adding potassium iodide solution to lead nitrate solution.
A chemical reaction results in new substances by undergoing certain reactions and There will be reactants on the left hand side and products on the right hand side. An example for chemical reaction is An example of combustion is methane + oxygen forms carbon dioxide and water. This can be written as a balanced symbol equation: CH4 + 2O2 →CO2 + 2H2O When dilute sulphuric acid is poured over zinc granules heat will libe
- ChemistryClass 10ICSE
Fill in the following blanks with suitable words: (a) Chemical equations are balanced to satisfy the law of . A solution made in water is known as an solution and indicated by the symbo
Conservation of mass Aqueous; (aq)
- ChemistryClass 10ICSE
Balance the following equations: (i) Na + O2 → Na2O (ii) H2O2→ H2O + O2 (iii) Mg(OH)2 + HCl → MgCl2 +H2O (iv) Fe +O2 → Fe2O3 (v) Al(OH)3 → Al2O3 +H2O (vi) NH3 + CuO → Cu +N2 +H2O (vii) Al2(SO4)3 + NaOH → Al(OH)3 + Na2SO4 (viii) HNO3 +Ca(OH)2 → Ca(NO3)2 (ix) NaOH +H2SO4 → Na2SO4 +H2O (x) BaCl2 + H2SO4 → BaSO4 +HCl
4Na + O2 → 2Na2O 2H2O2 → 2H2O + O2 Mg(OH)2 + 2HCl → MgCl2 + 2H2 4Fe + 3O2 → 2Fe2O3 2Al(OH)3 → Al2O3 + 3H2O 2NH3 + 3CuO → 3Cu + N2 + 3H2O Al2(SO4)3 + 6NaOH → 2Al(OH)3 + 3Na2SO4 2HNO3 + Ca(OH)2→ Ca(NO3)2 + 2H2O 2NaOH + H2SO
- ChemistryClass 10ICSE
Write complete balanced equations for the following reactions: (a) Calcium (solid) + Water (liquid) →Calcium hydroxide (solution) + Hydrogen (gas) Sulphur dioxide (gas) + Oxygen (gas) → Sulphur trioxide (gas)
Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g) 2SO2 (g) + O2 (g) → 2SO3 (g)
- ChemistryClass 10ICSE
1. Correct and balance the following equations: (i) Ca + H2O → CaOH + H (ii) N + H → NH3
Ca + 2H2O → Ca(OH)2 + H2 N2 + 3H2 →2NH3
- ChemistryClass 10ICSE
Complete and balance the following equations: (a) NaOH + → Na2SO4 + H2O (b) Ca(OH)2 + → CaCO3 + H2O
2NaOH + H2SO4 → Na2SO4 + 2H2O Ca(OH)2 + CO2 → CaCO3 + H2O
- ChemistryClass 10ICSE
Write the balanced chemical equations for the following reactions: (a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water (b) Aluminium + Copper chloride → Aluminium chloride + Copper
Ca(OH)2 + CO2 → CaCO3 + H2O 2Al + 3CuCl2 → 2AlCl3 + 3Cu
- ChemistryClass 10ICSE
Translate the following statements into chemical equations and then balance the equations: (a) Hydrogen sulphide gas burns in air to give water and sulphur dioxide. (b) Phosphorus burns in oxygen to give phosphorus pentoxide. (c) Carbon disulphate burns in air to give carbon dioxide and sulphur dioxide. (d) Aluminium metal replaces iron from ferric oxide, Fe2O3, giving aluminium oxide and iron. (e) Barium chloride reacts with zinc sulphate to give zinc chloride and barium sulphate.
2H2S + 3O2 → 2H2O + 2SO2 P4 + 5O2 → 2P2O5 CS2 + 3O2 → CO2 + 2SO2 2Al + Fe2O3 →Al2O3 + 2Fe BaCl2 + ZnSO4 →ZnCl2 + BaSO4
- ChemistryClass 10ICSE
How will you indicate the following effects in a chemical equation? (a) A solution made in water (b) Exothermic reaction Endothermic reaction
The solution made in water can be indicated by the symbol (aq) which shows it is aqueous An exothermic reaction can be indicated by Heat, heat energy or energy on the product side An endothermic reaction can be indicated by Heat, heat energy or energy on the reactant side
- ChemistryClass 10ICSE
Why is photosynthesis considered an endothermic reaction?
Endothermic reactions are those which heat is absorbed in the reaction. As we know that photosynthesis is a process that green plants and some other organisms use sunlight to synthesize food from carbon dioxide and water and turns to oxygen and glucose. Plants absorb direct energy from sun thus considered photosynthesis as endothermic reaction
- ChemistryClass 10ICSE
What does the symbol (aq) represent in a chemical equation?
In a chemical equation (aq) always represents for aqueous solution
- ChemistryClass 10ICSE
What is wrong with the following chemical equation? Mg + O → MgO Correct and balance it.
Oxygen should be in molecular form, O2 2Mg + O2 → 2MgO
- ChemistryClass 10ICSE
State whether the following statement is true or false: A chemical equation can be balanced easily by altering the formula of a reactant or product.
False
- ChemistryClass 10ICSE
Why should magnesium ribbon be cleaned before burning in air?
Magnesium ribbon is made up of pure magnesium metal and it is highly reactive with oxygen which further leads to the oxidation of magnesium when it comes in contact with air. On the surface of the magnesium ribbon it forms a layer of oxide and act as a protective layer. So it is necessary to clean the magnesium ribbon before burning in air
- ChemistryClass 10ICSE
What happens chemically when quicklime is added to water filled in a bucket?
Quick lime is chemically calcium oxide. When it is added to water filled in a bucket, it forms calcium hydroxide (slaked lime) and reacts vigorously by releasing large amount of heat which is an exothermic reaction.
- ChemistryClass 10ICSE
On what basis is a chemical equation balanced?
A chemical equation is always balanced by comparing the number of atoms of each element on reactant side as well as product side. It is based on the Law of conservation of mass, i.e. number of atoms on the left hand side should be equal to the right hand side
- ChemistryClass 10ICSE
Why is respiration considered as an exothermic process?
Exothermic reaction is a reaction in which the energy is liberated. In the process of respiration, energy is released thus considered as an exothermic reaction