Answer:
2.8
Explanation:
First, we will calculate the molarity of the acetylsalicylic acid solution.
M = mass of solute (g) / molar mass of solute × volume of solution (L)
M = 0.327 g / 180.158 g/mol × 0.237 L
M = 7.66 × 10⁻³ M
For a weak acid such as acetylsalicylic acid, we can find the concentration of H⁺ using the following expression.
[H⁺] = √(Ca × Ka)
where,
Ca: concentration of the acid
Ka: acid dissociation constant
[H⁺] = √(7.66 × 10⁻³ × 3.3 × 10⁻⁴)
[H⁺] = 1.6 × 10⁻³ M
The pH is:
pH = -log [H⁺]
pH = -log 1.6 × 10⁻³ = 2.8
According to the periodic table, carbon's molar mass is 12.011 grams per mole (that's the small number under the element). So, just multiply like this to get the answer:

So, there are approximately 0.208 grams in 2.5 moles of carbon.
I don't exactly know but probably so.
Answer:
Br
|
Br-P-Br
|
Br
Explanation:
To calculate the valance electrons, look at the periodic table to find the valance electrons for each atom and add them together. P is in column 5A, so it has 5, Br is in column 7A, so it has 7 (multiply by 4 since there are 4 Br atoms to give 28) and there is a 1- charge, so add one more electron. 5+28+1=34, so there are 34 electrons to place. P would be the central atom, so place it in the middle. Place each Br around the P (as shown above) with a a single line connecting it. Each line represents 2 electrons, so 8 total have been place, leaving 26 remaining. Place 6 electrons around each Br (2 on each of the unbonded sides), which leaves 2 electrons remaining. The remaining pair of unbound electrons will be attached to the P between any two Br atoms. Phosphorus doesn't have to follow the octet rule, so it actually ends up with 10 valance electrons.