Advertisements
Advertisements
Question
Write any two observations in an activity which may suggest that a chemical reaction has taken place. Give an example in support of your answer.
Advertisements
Solution
Two observations that may suggest that a chemical reaction has taken place are
(i) evolution of a gas and
(ii) change in temperature.
For example, zinc granules react with dilute sulphuric acid to evolve hydrogen gas, which is easily observed by the bubbles of hydrogen gas appearing around zinc granules. Also, the flask becomes hot, which shows heat is evolved during the reaction—that is, change in temperature.
Zn + H2SO4 → ZnSO4 + H2↑ + Heat
RELATED QUESTIONS
Balance the following chemical equation.
\[\ce{NaCl + AgNO3 -> AgCl + NaNO3}\]
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 products.
State one characteristic of the chemical reaction which takes place when dilute hydrochloric acid is added to sodium carbonate.
What happens when silver nitrate solution is added to sodium chloride solution?
Write the equation for the reaction which takes place.
A white precipitate will be formed if we add common salt solution to:
(a) Ba(NO3)2 solution
(b) KNO3 solution
(c) AgNO3 solution
(d) Mg(NO3)2 solution
Write the balanced equation for the following chemical reaction.
\[\ce{Barium chloride + Aluminium sulphate -> Barium sulphate + Aluminium chloride}\]
Write word equation for the following skeletal equation:
\[\ce{Ca + O2 → CaO}\]
Write word equation for the following skeletal equation:
\[\ce{KNO3 -> KNO2 + O2}\]
Balance the following chemical equation :
Na2CO3 + HCl → NaCI + H2O + CO2
Balance the following equation Also name the product formed.
`"K" + "CI"_2 → "KCI"`
Balance the following equation. Also name the product formed.
`"CO" + "O"_2 → " CO"_2`
Dry raisins were soaked in water for 2 hours, to determine the percentage of water absorbed by raisins. Before final weighing of swollen raisins, the extra water left on the surface of soaked raisins was removed by:
What information does the following chemical equation convey?
Zn + H2SO4 → ZnSO4+ H2
When a potassium iodide solution is added to a solution of lead (II) nitrate in a test tube, a precipitate is formed.
What is the colour of this precipitate? Name the compound precipitated.
When a potassium iodide solution is added to a solution of lead (II) nitrate in a test tube, a precipitate is formed.
Write the balanced chemical equation for this reaction.
A student mixes sodium sulphate powder in barium chloride powder. What change would the student observe on mixing the two powders? Justify your answer and explain how he can obtain the desired change.
What is meant by ‘reactants’ and ‘products’ in a chemical equation?
\[\ce{2KClO3->[MnO2] 2KCl + 3O2[g] - is a balanced equation.}\]
Give a reason why the above equation is balanced.
Underline the compound in the equation given below, it is incorrectly balanced and write the correct balancing for the same.
CaC2 + N2 → 2CaCN2 + C
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.
