Nuclear Chemistry
1. Gamma rays are electromagnetic radiations of wavelengths of 10-6 to 10-5 cm. (1983)
Ans: False
2. In β-emission from a nuclues the atomic number of the daughter element decreases by one. (JEE 1990).
Answer: False
In β-emission, number of protons in the nucleus goes up by one.
3. In a given electric field, β-particles are deflected more than α-particles having larger charge. (JEE 1993)
True
The deflection of the particle depends on the acceleration produced in it. The acceleration depends on the force and mass. Thus, in case of electric field it depends on the e/m of the particles. For β-particles, e/m is larger than α-particles because electrons are very very light than He+ species. So charge on helium particle is only twice high but mass is very very high.
Nuclear Chemistry
1. An element under [A,Z]M undergoes an α-emission followed by two successive β-emissions. The element formed is __________ . (JEE 1982)
answer: [A-4, Z]M
2. The number of neutrons in the parent nucleus which gives 14N on beta emission is __________ . (JEE 1985)
Answer: 8
Reason: One proton increases to give 7 protons of nitrogen. Hence before beta emission there are 8 neutrons and 6 protons.
3. A radio active nucleus decays emitting one alpha and two beta particles; the daughter nucleus is ___________ of the parent. (JEE 1989)
Answer: isotope
Reason; Z is same but A is different.
Surface Chemistry
1. The absorption of hydrogen by palladium is commonly known as ___________ .
(JEE 1983)
Answer: occlusion
Chemical Kinetics
1. The rate of chemical change is directly proportional to ______________. (JEE 1985)
Answer: concentration of reactants
2. In the Arrhenius equation, k = A exp(-E0/RT), A may be termed as the rate constant at ____________ . (JEE 1997)
Answer: Very high temperature or zero activation energy.
As k becomes equal to A in either case.
1. Gamma rays are electromagnetic radiations of wavelengths of 10-6 to 10-5 cm. (1983)
Ans: False
2. In β-emission from a nuclues the atomic number of the daughter element decreases by one. (JEE 1990).
Answer: False
In β-emission, number of protons in the nucleus goes up by one.
3. In a given electric field, β-particles are deflected more than α-particles having larger charge. (JEE 1993)
True
The deflection of the particle depends on the acceleration produced in it. The acceleration depends on the force and mass. Thus, in case of electric field it depends on the e/m of the particles. For β-particles, e/m is larger than α-particles because electrons are very very light than He+ species. So charge on helium particle is only twice high but mass is very very high.
Nuclear Chemistry
1. An element under [A,Z]M undergoes an α-emission followed by two successive β-emissions. The element formed is __________ . (JEE 1982)
answer: [A-4, Z]M
2. The number of neutrons in the parent nucleus which gives 14N on beta emission is __________ . (JEE 1985)
Answer: 8
Reason: One proton increases to give 7 protons of nitrogen. Hence before beta emission there are 8 neutrons and 6 protons.
3. A radio active nucleus decays emitting one alpha and two beta particles; the daughter nucleus is ___________ of the parent. (JEE 1989)
Answer: isotope
Reason; Z is same but A is different.
Surface Chemistry
1. The absorption of hydrogen by palladium is commonly known as ___________ .
(JEE 1983)
Answer: occlusion
Chemical Kinetics
1. The rate of chemical change is directly proportional to ______________. (JEE 1985)
Answer: concentration of reactants
2. In the Arrhenius equation, k = A exp(-E0/RT), A may be termed as the rate constant at ____________ . (JEE 1997)
Answer: Very high temperature or zero activation energy.
As k becomes equal to A in either case.
0 on: "Exam questions on Surface Chemistry/ Nuclear Chemistry"