Which substance can be decomposed chemically (1) cao and ca (2)mgo and mg (3) co and co (4) cao and mgo

Answer;

4) CaO and MgO

Explanation;

-Both CaO and MgO are compounds .

-Compounds are substances that are formed when two or more chemical elements are chemically bonded together. CaO is formed when Calcium and oxygen atom chemically combine while MgO is formed when magnesium atom and oxygen atom chemically combines.

-While elements can not be broken down (decomposed) into simpler substances by chemical means, compounds can be broken down into simpler substances chemically (into constituent atoms).

your answer would be a. 12.5 kg

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml