Answer:
The answer for number one is .A
The answer for number two is heat rises
Explanation:
Answer: 0.0345 sec
Explanation:
Rate law says that rate of a reaction is directly proportional to the concentration of the reactants each raised to a stoichiometric coefficient determined experimentally called as order.
![Rate=k[H_3PO_4]^2](https://tex.z-dn.net/?f=Rate%3Dk%5BH_3PO_4%5D%5E2)
k= rate constant = 
Expression for rate law for first order kinetics is given by:

where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
for completion of 20 % of reaction



The time taken for the concentration of
to decrease to 20% to its natural value is 0.0345 sec
In an unsaturated solution, the amount of solute is less than required in the solution. So, it can dissolve more solute.
Solid state is more dense than the liquid state as the molecules are closely packed in a solid.
Density is temperature dependent as with increase in temperature volume increases. So, the density decreases.
Like dissolves like. A polar solute will dissolve in a polar solvent.
So, the correct statement among the given options is B.For most substances, the solid state is more dense than the liquid state.
Electrovalent or ionic bonding
Answer:
Elements only contain one type of atoms while compounds contain two or more types of atoms.
Explanation:
An example of an element is sodium --> Na (only Na atoms)
An example of a compound can be water --> H2O (contain H and O atoms)
*But the particles within a compound are all the same.