The correct option is A,
Isotopes are atoms of an element, which have the same number of protons but different number of neutrons in the nucleus of the atom. Thus, isotopes have the same atomic number but different mass number.
Looking at the options given above, you will discover that Chlorine which is given in option A is correct. Both type of chlorine has the same atomic number, which is 17, but they have different atomic masses, the atomic mass of the first one is 35 while that of the second one is 37.<span />
Answer: 250 ml of stock solution with molarity of 12.0 M is measured using a pipette and 250 ml of water is added to volumetric flask of 500 ml to make the final volume of 500 ml.
Explanation:
According to the dilution law,

where,
= concentration of stock solution = 12.0 M
= volume of stock solution = ?
= concentration of diluted solution= 6.00 M
= volume of diluted acid solution = 500 ml
Putting in the values we get:


Thus 250 ml of stock solution with molarity of 12.0 M is measured using a pipette and 250 ml of water is added to volumetric flask of 500 ml to make the final volume of 500 ml.
Evaporation occurs when water molecules on the surface gain enough energy to enter the atmosphere. However, stronger intermolecular forces between water molecules cause them to be strongly attracted to each other and to tend to stay in the liquid phase. When the temperature is raised (when heat is applied), more molecules gain the energy needed to escape these intermolecular forces and go into the vapor phase.
Therefore the best answer is D.
The First 2 statements stated above were false whereas the third one is a true statement.
Explanation:
- The viscosity of bitumen is about 100 times greater than the viscosity of water - False
Reason - The viscosity of bitumen is about not 100 times greater than the viscosity of water, it is actually 100, 000 times greater.
- Oil from oil sand deposits is only obtained by first heating the sands at high temperatures is False.
Reason- Oil from oil sand deposits is not obtained by first heating the sands at high temperatures but by using steams
- Oil sands contain sand, water, and light crude oil is true.