Answer:
a. 0.119mol Kr
Explanation:
To solve this problem, we must understand that;
Mass = number of moles x molar mass
Molar mass of Kr = 83.3g/mol
Ar = 40g/mol
He = 4g/mol
Ne = 20.18g/mol
a0.119 mol Kr mass = 0.119 x 83.3 = 9.9g
b 0.400 mol Ar mass = 0.4 x 40 = 16g
C 1.25 mol He mass = 1.25 x 4 = 5g
d 2.02 mol Ne mass = 2.02 x 20.18 = 40.8
Krypton is the answer
Answer:
Considering the half-life of 10,000 years, after 20,000 years we will have a fourth of the remaining amount.
Explanation:
The half-time is the time a radioisotope takes to decay and lose half of its mass. Therefore, we can make the following scheme to know the amount remaining after a period of time:
Time_________________ Amount
t=0_____________________x
t=10,000 years____________x/2
t=20,000 years___________x/4
During the first 10,000 years the radioisotope lost half of its mass. After 10,000 years more (which means 2 half-lives), the remaining amount also lost half of its mass. Therefore, after 20,000 years, the we will have a fourth of the initial amount.
With a physical change you can actually see it change like ice turning into water, then with a chemical change you can't see it change, although within the molecules themselves they change which makes that possible.
Hope this helps!
Answer:
- <em>A solution that contains many dissolved molecules in a fixed amount of solution is called</em> <u>concentrated</u>.
Explanation:
Solutions are homogeneous mixtures.
A solution contains at least one solute component and one solvent component all in the same phase.
The term solubility is used to express the maximum amount of solute that can be dissolved in certain amount of solvent, and is measured at a given temperature and pressure.
You may refer to a solution as <em>concentrated</em> or diluted. These are kind of vague terms, in the sense that they do not express how much solute is dissolved. They just tell if there are many dissolved particles (molecules or ions), which is expressed as concentrated, or just a few particle, which is express as diluted.
Other more specific terms used to refer the amount of solute dissolved in a solution are: unsaturated solution, saturated solution, and supersaturated solution.
<u>Unsaturated solution</u>: the solution contains less solute than what it can have. The solution may dissolve more solute.
<u>Saturated solution</u>: the solution has the maximum amount of solute that it can dissolve, at certain temperature and pressure. If you add more solute to a saturated solution, it will not get dissolved (unless you change the temperature or pressure).
<u>Supersaturated solution</u>: a special condition where the solution contains more solute than the saturated solution, at the same temperature and pressure. This is a very unstable situation and any perturbation will make that the excess solute precipitate.
