True
the definition of matter is any substance that has mass and takes up space.
Answer:
snow and very low temperatures are predicted for tomorrow.
Explanation:
snow and very low temperatures are associated with average weather condition of a place thus making it a statement about climate.
Answer: (C) Dissolution is the process by which a solute form a solution in a solvent.
Explanation: Dissolution can be described as the process by which a solute dissolves in a solvent to give a solvent.
The solute may be a solid, liquid or gas and solvent is usually a liquid but can also be liquid, gas or supercritical fluid. The most common solvent is water and it is referred to as the universal solvent.
Example are:
1.Stirring of sugar in water.
In this case the solute is the sugar and the solvent is water.
2.Organic substances dissolves readily in solvent like kerosene and benzene and they are known as non-polar solvent while the organic substances are the solute
Answer: Energy of reactants = 30, Energy of products = 10
Exothermic
Activation energy for forward reaction is 10.
Explanation:
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and 
for the reaction comes out to be negative.
Energy of reactants = 30
Energy of products = 10
Thus as energy of the product < energy of the reactant, the reaction is exothermic.
Activation energy 
is the extra energy that must be supplied to reactants in order to cross the energy barrier and thus convert to products.
for forward reaction is (40-30) = 10.
To calculate the average mass of the element, we take the summation of the product of the isotope and the percent abundance. In this case, the equation becomes 186.207=187*0.626+185*x where x is the percent abundance of 185. The answer is 0.374 or 37.4%. This can also be obtained by 100%-62.6%= 37.4%.
