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प्रश्न
What are products? Explain with the help of example.
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उत्तर
- The substances formed as a result of a chemical reaction by the formation of new bonds are called products.
- e.g. Decomposition of calcium carbonate by heating to form calcium oxide and carbon dioxide is a chemical reaction. In this reaction, calcium carbonate is the reactant while calcium oxide and carbon dioxide are the products.
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संबंधित प्रश्न
Methyl orange is used as an indicator. It shows colour change in acid, base and neutral substance. Tabulate your result as follows:
| Indicator | Colour change | Inference |
| Methyl Orange | No change | ...................... |
| .................... | Acid | |
| Yellow | ....................... |
Translate the following statement into chemical equation and then balance the equation:
Phosphorus burns in oxygen to give phosphorus pentoxide.
What is a chemical equation? Explain with the help of an example.
With the help of an appropriate example, justify that some of the chemical reactions are determined by Evolution of a gas.
Give chemical equation for the reaction involved in the above case.
With the help of an appropriate example, justify that some of the chemical reactions are determined by Change in temperature.
Give chemical equation for the reaction involved in the above case.
Give one example of a chemical reaction characterised by change in state.
State one characteristic of the chemical reaction which takes place when wax is burned in the form of a candle?
Is Photosynthesis an endothermic reaction or an exothermic reaction?
One of the following does not happen during a chemical reaction. This is:
(a) Breaking of old chemical bonds and formation of new chemical bonds
(b) Formation of new substances with entirely different properties
(c) Atoms of one element change into those of another element to form new products.
(d) A rearrangement of atoms takes place to form new products.
A metal X forms a salt XSO4. The salt XSO4 forms a clear solution in water which reacts with sodium hydroxide solution to form a blue precipitate Y. Metal X is used in making electric wire and alloys like brass.
(a) What do you think metal X could be?
(b) Write the name, formula and colour of salt XSO4.
(c) What is the blue precipitate Y?
(d) Write a chemical equation of the reaction which takes place when salt XSO4 reacts with sodium hydroxide solution. Give the state symbols of all the reactants and products which occur in the above equation.
Balance the following chemical equation:
A colourless lead salt, when heated, produces a yellow residue and brown fumes.
(a) Name the lead salt.
(b) Name the brown fumes.
(c) Write a chemical equation of the reaction involved.
Write word equation for the following skeletal equation:
\[\ce{FeCl2 + Cl2 -> FeCl3}\]
Write symbolic representation for the following word equation and balance them :
Aluminium + Chlorine → Aluminium chloride.
Balance the following equation .
N2 + O2 → NO
Balance the following equation. Also name the product formed.
PbCO3 → PbO +CO2
Write the chemical equation for the following word equation and balance them.
Sodium reacts with water to form sodium hydroxide and hydrogen
Balance the following equation:
PbS + O2 → PbO + SO2
Balance the following equation:
C + H2SO4 → CO2 + H2O + SO2
Balance the following equation:
NO2 +H2O → HNO2 + HNO3
What information do the following chemical equations convey? Mg + 2HCl → MgCl2+ H2
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
0.02 moles of pure MnO2 is heated strongly with conc. HCl. Calculate moles of chlorine gas formed.
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
0.02 moles of pure MnO2 is heated strongly with conc. HCl. Calculate the mass of chlorine gas formed.
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
0.02 moles of pure MnO2 is heated strongly with conc. HCl. Calculate moles of acid required.
(a) Give only one suitable chemical test to identify the following gases.
- Ammonia
- Sulphur dioxide
- Hydrogen Chloride
- Chlorine
- Carbon Dioxide
- Oxygen
- Hydrogen
(b) Select a basic gas mentioned in Q.1 (a). How is the basic nature suspected?
(c)Select acidic gases from the gases mentioned in Q.1 (a). How is the acidic nature suspected?
(d) State the gas responsible for bleaching action.
(e)Which gas turn blue cobalt chloride paper light pink?
How is a flame test performed?
Answer the following question:
How do acids and bases react with each other? What is the name of the process? What product is obtained from these reactions?
Name the substances that are getting oxidised and reduced in the process.
Write word equation for the following molecular equation:
CuCo3 → CuO + CO2 [g]
Word equation:
State the characteristics or indications occurring in the above reaction.
Write word equation for the following molecular equation:
\[\ce{NH3 [g] + HCl [g] ⇌ NH4Cl [s]}\]
Word equation:
State which characteristic is observed in the above reaction.
Give an-example of a similar above characteristic, seen between two other gaseous reactants.
A chemical reaction is generally accompanied by certain external indications or characteristics. These include – change of – (a) colour (b) state (c) smell (d) evolution of gas (e) formation of precipitate (f) evolution or absorption of heat. With reference to change of colour – state the change in colour seen when the following are heated – lead [IV] oxide.
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:
Lead nitrate to ammonium hydroxide.?
Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.
Light energy
Name the following:
Two non-metal which react explosively when brought in close contact.
Balance the following simple equation:
ZnS + O2 → ZnO + SO2
Balance the following simple equation:
K + H2O → KOH + H2
Balance the following chemical equation.
- Na + O2 → Na2O3
- Ca + N2 → Ca3N2
- N2 + H2 →NH3
- CaCO3 +HCl → CaCl2 + CO2 +H2O
- Pb(NO3)2 → PbO + NO2 + O2
The following reaction is an example of a `4"NH"_3("g") + "SO"_2 -> 4"NO"("g") + 6"H"_2"O"("g")`
- displacement reaction
- combination reaction
- redox reaction
- neutralisation reaction
Which of the following are exothermic processes?
- Reaction of water with quick lime
- Dilution of an acid
- Evaporation of water
- Sublimation of camphor (crystals)
