Answer:
1) 90.0 mL
2) 11.25 M
3) 0.477 M
4) 144 mL
Explanation:
The main formula that will be used for all these calculations is:
C₁V₁ = C₂V₂
C stands for concentration and V stands for volume and the subscripts 1 and 2 indicate an initial concentration or volume and a final concentration or volume.
For each problem, it's best to start by figuring out what you have and what you need to find. Figure out if you're looking for an initial value or a final value.
1) We need to find the initial volume. So, take what values you have and plug them in and then solve for whatever variable:
5.00 M · V₁ = 500.0mL · 0.900 M - divide by 5.00
C₁ = 90.0 mL
2) This time we're finding the initial concentration:
20.0mL · C₁ = 150.0mL · 1.50 M - divide by 20.0mL
C₂ = 11.25 M
3) Now we're finding the final concentration:
12.00mL · 3.50 M = 88.0mL · C₂ - divide by 88.0mL
C₂ = 0.477 M
4) Finally, we're looking for the final volume:
9.0mL · 8.0 M = 0.50 M · V₂ - divide by 0.50 M
V₂ = 144mL
D. The number of electrons equals the atomic number for a neutral element. Each number after the letter refers to the number of electrons in that shell. So for D, 2+2+6+2+6+2 = 20 electrons, which is equal to the atomic number.
Answer:
C. Fluorine because the model has 9 protons which is represented by the atomic number
Explanation:
We usually identify an element by the number of protons in them. The number of protons is the atomic number of an atom.
- Every atom has a specific number of protons in them.
- This number of protons is the atomic number.
- According to the periodic law, atoms are arranged on the periodic table based on their atomic number.
- The given fluorine atom has 9 protons which represents the atomic number of the atom.
- This way, the given number clearly shows the right model for identifying the chemical specie.
Purple stem plants can be formed by genetics, they use their energy slightly different from other plants, they use less energy, but that may also be because of bad nutrition, and because they may be hungry for nutrients.
