CHEMISTRY

 


The soul of chemistry is its dealing with
a. Internal structural changes in matter
b. Composition of matter
c. Properties of matter
d. Composition and properties of matter


All of the following statements are incorrect for 20 mol of hydrogen peroxide
except
a. it has 20 mol of hydrogen atoms
b. it has 30 mol of oxygen atoms
c. it has 80 mol of atoms
d. 30 mol of hydrogen atoms


If proton number of two atoms is same then it can be concluded that
a. they are isotopes
b. compounds of both with CI2 will be similar in reactivity towards other
compounds
c. both have same colors
d. both have same melting points


A chemist poured lemon juice on soil, the idea that he may have in his mind is
that
a. there may be a possibility of a chemical reaction
b. lemon juice is dangerous to health
c. lemon juice is dangerous to health
d. water should be preferred over lemon juice for drinking


Dr. Khan has discovered two isotopes of an element with atomic number 119.
The relative abundance of isotopes 119Uue300 and 119Uue305 is 70% and 30%
respectively. The average atomic weight of Uue is

301.5 a.m.u
b. 302.5 a.m.u
c. 303.5 a.m.u
d. 304.5 a.m.u


Which of the following is not related to a.m.u
a. gram
b. kilogram
c. microgram
d. gram/lit


The number of significant figures in 0.00200 is
a. two
b. three
c. five
d. one


All of the following statements are incorrect except
a. precision and accuracy should go side by side in a scientific work
b. scientific work must be precise, accuracy is not essential
c. scientific work must be accurate, precision is not essential
d. +calculations must be made before any experiment


Empirical formula and formula unit of an ionic compound
a. are always similar
b. are always different
c. may be similar or different
d. ionic compounds don’t’ have any empirical formula


Copper (II) oxide is mixed with organic compound during combustion analysis.
The purpose is
a. to carry out complete combustion
b. to reduce the economy of the process
c. to reduce the time for completion of the reaction
d. all of the above


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