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प्रश्न
How will you indicate Exothermic reaction in a chemical equation?
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उत्तर
Exothermic reaction is indicated by writing “heat” or “heat energy” or “energy” on the products’ side of a chemical reaction.
Example: CH4 + 2O2 → CO2 + 2H2O + Heat
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संबंधित प्रश्न
Giving examples, state the difference between balanced and unbalanced chemical equations.
When water is added gradually to a white solid X, a hissing sound is heard and a lot of heat is produced forming a product Y. A suspension of Y in water is applied to the walls of a house during white washing. A clear solution of Y is also used for testing carbon dioxide gas in the laboratory.
(a) What could be solid X? Write its chemical formula.
(b) What could be product Y? Write its chemical formula.
(c) What is the common name of the solution of Y which is used for testing carbon dioxide gas?
(d) Write chemical equation of the reaction which takes place on adding water to slid X.
(e) Which characteristic of chemical reactions is illustrated by this example?
The metal M reacts vigorously with water to form a solution S and a gas G. The solution S turns red litmus to blue whereas gas G, which is lighter than air, burns with a pop sound. Metal M has a low melting point and it is used as a coolant in nuclear reactors.
(a) What is metal M?
(b) What is solution S? Is it acidic or alkaline?
(c) What is gas G?
(d) Write a balanced chemical equation for the reaction which takes place when metal M reacts with water.
(e) Is this reaction exothermic or endothermic?
Balance the following chemical equation :
Na20 + H20 → NaOH
Balance the following equation. Also name the product formed.
FeCI2 + CI2 → FeCI3
Write your observation and name the product when An aqueous solution of barium chloride is added to dilute sulphuric acid.
Balance the equation stepwise.
Ag(s) + HCl(aq) → AgCl ↓+ H2 ↑
Write the chemical equation for the following word equation and balance them.
Calcium + Nitrogen → Calcium nitride
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
0.02 moles of pure MnO2 is heated strongly with conc. HCl. Calculate the volume of chlorine gas formed at S.T.P.
Write word equation for the following molecular equation:
\[\ce{CuSO4 + 2NaOH -> Na2SO4 + Cu(OH)2↓}\]
Word equation:
State the colour of the products.
In certain reaction an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in the following reaction involving addition of:
Dilute hydrochloric acid to silver nitrate.
What is meant by ‘reactants’ and ‘products’ in a chemical equation?
Balance the following simple equation:
NaHCO3 + H2SO4 → Na2SO4 + H2O + CO2
With reference to a chemical equation state which of the statements 1 to 5 pertain to A or B.
A: Information provided by a chemical equation.
B: Limitations of a chemical equation.
- The nature of the individual elements.
- The speed of the reaction.
- The state of matter in which the substance is present.
- The completion of the reaction.
- The direction of the reaction.
Underline the compound in the equation given below, it is incorrectly balanced and write the correct balancing for the same.
Cl2 + 2H2O + SO2 → 4HCl + H2SO4
In the chemical equation the _______ are written on the left-hand side.
Balance the given chemical reaction as per the instructions below.
\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]
Write the number of atoms of various elements in the reactants and products.
What is called thermolysis reactions?
Which of the following are exothermic processes?
- Reaction of water with quick lime
- Dilution of an acid
- Evaporation of water
- Sublimation of camphor (crystals)
Complete the following blank in the equation as indicated.
\[\ce{CaH2_{(s)} + 2H2O_{( aq)}-> Ca(OH)2_{(s)} + 2H2_{(g)}}\]
Grams: 42 g + ______ `→` ______ + ______
