(A) Helium
(B) Neon
(C) argon
(D) all of the above
8. What does one mean by exothermic and endothermic reactions ? Give examples.
9. Write word equations and then balanced equations for the reaction taking place whe
(a) dilute sulphuric acid reacts with zinc granules.
(b) dilute hydrochloric acid reacts with magnesium ribbon
10. What were the limitations of Newland's law of octaves ?
11. Differentiate between metal and non-metal on the basis of their chemical properties
12. Write the balanced equation for the following:
(a) Chemical reactions :
(i) Hydrogen + Chlorine → Hydrogen chloride
(ii) Sodium + Water Sodium Hydroxide + Hydrogen
(b)
Write molecular formula, condenses structural formula and IUPAC name of f
of alkyne homologous series.
Or
(a) Explain the following terms with one example each :
Answers
Answer:
8 = Chemical reaction that release energy in the form of heat light or sound are card exothermic reaction.
example - C + O2 ---------- CO2 + Heat
Reaction that absorb energy or require energy in order to proceed are called endothermic reaction.
example - Na + O2 ----------- 2NO
12 = a 1 H2 + Cl2 ------------ 2HCl
2 2Na + 2H2O ----------- 2NaOH + H2
11 = chemical properties of metal are
it is electron donor
it form cation means( + ions )
it is electropositive
chemical properties of non metal are
it is gainer of electron.
it form anion ( - ions )
it is electronegative.
9 = 1 H2SO4 + Zn -------- ZnSO4 + H2
2 2HCl + Mg -------- MgCl2 + H2
10 = Newland could arrange elements only up to calcium, out of the total 56 elements known.
After calcium, every eighth element did not possess properties similar to that of the first.
Only 56 elements were known at the time of Newlands, but later several elements were discovered.
Explanation:
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