Calculate the number of electrons constituting one coulomb of charge.
Charge is flow of number of electrons.
Q=ne
Q is charge, n = number, e = electron
Whereas, One electron possesses a charge of 1.6 × 10−19 C,
i.e., 1.6 × 10−19 C of charge is contained in 1 electron.
∴ 1 C of charge is contained in
Hence, 6x1018 electrons constitute one coulomb of charge.
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
Outline a project which aims to find the dominant coat colour in dogs.
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
How is the sex of the child determined in human beings?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
What is an homologous series? Explain with an example.
A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
Why is variation beneficial to the species but not necessarily for the individual?
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning.
An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be –
(a) 100 W (b) 75 W (c) 50 W (d) 25 W
A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.
Why is respiration considered an exothermic reaction? Explain.
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
If you could use any source of energy for heating your food, which one would you use and why?
How is the sex of the child determined in human beings?
Write the balanced equation for the following chemical reactions.
1. Hydrogen + Chlorine → Hydrogen chloride
2. Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
3. Sodium + Water → Sodium hydroxide + Hydrogen
How many structural isomers can you draw for pentane?
Samples of four metals A, B, C and D were taken and added to the following solution one by one. The results obtained have been tabulated as follows.
Metal | Iron(II) sulphate | Cooper(II) sulphate | Zinc sulphate | Silver nitrate |
A | No reaction | Displacement | ||
B | Displacement | No reaction | Displacement | |
C | No reaction | No reaction | No reaction | No reaction |