PHYSICS & CHEMISTRY
I Fall in the blanks:-
3 x 10 = 5
1. Formation of nitric oxide from nitrogen and oxygen is a
reaction.
2. New substance formed after a chemical reaction is called
3. A balanced chemical equation is always obeys a law of
4. The potato chips manufacturers' uses
gas to flush up the chips bags to prevent the
chips getting oxidized
5. Bases are generally identified by their
taste and
touch.
6.
is used for softening the hard water.
7
is used in pickling
8. Aquaregia is a Latin word which means
9. Electric current flows from
potential to
potential.
10. The device which is measure the potential difference is called
I Answer in one sentence:- (Any 5)
1x5 =
1. Define electric power. Mention its Sl unit.
2. How much energy is given to each coulomb of charge passing through a 6V battery?
3. Why do we apply paint on iron articles?
4. Why chemical equation should be balanced ?
5. What is the common name of CaoCl2?
6. What is roasting?
Answers
Answer:
1....Almost 181kJ of heat is absorbed during the reaction of Nitrogen and Oxygen to produce nitric oxide. Since heat is absorbed, the reaction is endothermic in nature.
2....A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.
3...law of conservation of mass
4....Potato chip bags are not full of air, but of nitrogen gas. This is done to prevent the chips from oxidizing, which is part of what makes them go stale. Oxygen is very reactive, and likes to combine with other molecules whenever it can, causing chemical changes to take place