Question

(a) State law of conversion of mass. Write down one limitation of this law

(b) Write down three differences between physical and chemical changes
(c) Give an example of a non-metal which has very high density

(d) Give one example of liquid metal.​

Answer 1

1)But in a nuclear reaction, some the mass gets converted into energy creating an imbalance between the mass of reactants and the products. ... Therefore, the total mass is not conserved. This is the limitation of the conservation of mass.

2)A chemical change is a permanent change. A Physical change affects only physical properties i.e. shape, size, etc. ... Some examples of

physical change are freezing of water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning

of coal, rusting, etc.

3)Iridium and osmium have the highest densities where as lithium has the lowest density.

4)Mercury: Mercury is the only metal at natural temperatures and pressure and is a vapor. ... Hence, an example of a liquid metal is mercury and that of a liquid non-metal is bromine. 

Answer 2

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✪The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations.

✪According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.

✪The law of conservation of mass is useful for a number of calculations and can be used to solve for unknown masses, such the amount of gas consumed or produced during a reaction.