Answer:
A and D
Explanation:
I took the test, and choose both B and C and got it wrong
Answer: (3) silicon
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane
, propanone
and water 
Well the formula for the volume of a cube is
V=length×width×height
so input it
V=25×5×15
V=1875 cubic meters
Answer:
473 year
Explanation:
Using integrated rate law for first order kinetics as:
Where,
is the concentration at time t
is the initial concentration
Given:
To reach 12.5% of reactant means that 0.125 of
is decomposed. So,
= 0.125
t = ?
t = 473 year