Answer:
Rubidium-85=61.2
Rubidium-87=24.36
Atomic Mass=85.56 amu
Explanation:
To find the atomic mass, we must multiply the masses of the isotope by the percent abundance, then add.
<u>Rubidium-85 </u>
This isotope has an abundance of 72%.
Convert 72% to a decimal. Divide by 100 or move the decimal two places to the left.
- 72/100= 0.72 or 72.0 --> 7.2 ---> 0.72
Multiply the mass of the isotope, which is 85, by the abundance as a decimal.
- mass * decimal abundance= 85* 0.72= 61.2
Rubidium-85=61.2
<u>Rubidium-87</u>
This isotope has an abundance of 28%.
Convert 28% to a decimal. Divide by 100 or move the decimal two places to the left.
- 28/100= 0.28 or 28.0 --> 2.8 ---> 0.28
Multiply the mass of the isotope, which is 87, by the abundance as a decimal.
- mass * decimal abundance= 87* 0.28= 24.36
Rubidium-87=24.36
<u>Atomic Mass of Rubidium:</u>
Add the two numbers together.
- Rb-85 (61.2) and Rb-87 (24.36)
Answer:
Red
Explanation:
Violet - shortest wavelength, around 400-420 nanometers with highest frequency. They carry the most energy.
Indigo - 420 - 440 nm
Blue - 440 - 490 nm
Green - 490 - 570 nm
Yellow - 570 - 585 nm
Orange - 585 - 620 nm
Red - longest wavelength, at around 620 - 780 nanometers with lowest frequency and least amount of energy
Therefore, <em>red </em>is the answer you're looking for.
I hope this helps and that you have a great day! :)
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.
Answer: They are less stable
Explanation:
Answer:
12
Explanation:
You will need a chemical equation with masses and molar masses, so let’s gather all the information in one place.
: 258.21 18.02
KAl(SO₄)₂·xH₂O ⟶ KAl(SO₄)₂ + xH₂O
Mass/g: 4.74 2.16
Step 1. Calculate the mass of the KAl(SO₄)₂.
Mass = 4.74 g – 2.16 g = 2.58 g.
Step 2. Calculate the moles of each product.
Step 3. Calculate the molar ratio of the two products.
1 mol of KAl(SO₄)₂ combines with 12 mol H₂O, so x = 12.
