Prep Worksheet -1
Language of chemistry
Q1. Answer the following questions:I.
What is meant by the term symbol? Give two examples
Ans-
II.
Explain the term valency. State why the valency of potassium metal is +1 and non metal
chlorine is-1.
Ans –
III.
What is meant by the term variable valency? give examples
Ans –
IV.
Give the valency in each case and name the element:a) K
b) Cr2O7
c) Cl
d) Ni
e) Br
f) Ba
g) I
h) Zn
i) ClO
j) Al
k) OH
l) C
m) CO
n) N
o) H
p) Ca
q) Li
r) Mg
s) Cr
V.
What do the symbols given below represent in a chemical equation:a) 
b) (s)
c) (l)
d) (g)
e) (aq)
VI.
Explain the meaning of the term compound with a suitable example. State the main
characteristics of a compound.
Ans –
VII.
Explain the term chemical formula. State why the molecular formula of zinc carbonate is
ZnCO3.
Ans –
VIII.
Fill in the blanks :a) A symbol represent a short form of a /an…………………………[atoms/element/molecule]
b) Compounds are also ……………………………..[heterogeneous/homogeneous]in nature.
c) Variable valency is exhibited ,since electrons are lost from an element from the
………………………………….[valency/penultimate]shell.
d) A chemical equation is a short hand form for a ………………………………..
[physical/chemical]change.
IX.
X.
Balance the following simple equations:a) C
+
O2


O2
CO
b) N2
+
c) ZnS
+
O2

ZnO
d) Al
+
O2

Al2O3
e) Mg
+
N2

Mg3N2
f) NO
+
O2

NO2
g) NaHCO3
+
H2SO4 
Na2SO4

H2O

H2O
h) NaOH
+
H2SO4

Na2SO4
i) FeCl3
+
NaOH 
NaCl
+
j) CuSO4
+
NaOH

Na2SO4
Fe(OH)3
Write balanced equation for the following word equation:a) Potassium nitrate  potassium nitrate + oxygen
b) Calcium + water  calcium hydroxide + hydrogen
c) Iron + hydrochloric acid  iron [II]chloride + hydrogen
d) Nitrogen dioxide + water +oxygen nitric acid
e) Lead[IV]oxide  Lead monoxide + oxygen.
NO

+ Cu(OH)2
+SO2
+
CO2