Olympic cyclist fill their tires with helium to make them lighter. Calculate the mass of air in an air filled tire and the mass

Response:

This is my understanding.

Explanation:

(g) Titration curves

While I can't create two curves on a single graph, I can depict them separately for clarity.

In part (d), the graph indicated an equivalence point at 20 mL.

For the second titration, since the NaOH concentration is doubled, the volume to reach the equivalence point will be halved — 10 mL.

Below are the two titration curves.

(h) Evidence of reaction

Both HCl and NaOH are colorless solutions.

There is no gas released or precipitate formed during their reaction.

It’s likely the student observed that the Erlenmeyer flask heated up, indicating a chemical change.

Answer: second option: 1.70 to 1.40

Explanation:

1) pH is defined using the formula pH = - log [H₃O⁺]

2) Given that the initial concentration is x and after doubling it becomes 2x, we calculate:

pHi = - logx
pHf = - log 2x = - log 2 - logx

Thus, pHf - pHi = - log2 - logx - (- logx) = - log2 ≈ - 0.30

⇒ pHi - pHf = 0.30, indicating that the final pH (with twice the hydronium ions) is 0.30 lower than the starting pH.

3) The only option that indicates a 0.30 decline in pH is the second one: from 1.70 to 1.40. Therefore, that is the correct choice.

The result is 0.14303691.

Carbon-13 (¹³C) is a stable isotope of carbon with a mass number of 13, composed of six protons and seven neutrons.

Isotopes are elements that share the same atomic number but have different mass numbers, meaning they have a varying number of neutrons.

ω(¹³C) = 1.10% ÷ 100%.

ω(¹³C) = 0.0110; this indicates the natural abundance of carbon-13.

m(¹³C) = 13.003355; the atomic mass assigned to carbon-13.

ω(¹³C) · m(¹³C) = 0.0110 · 13.003355.

ω(¹³C) · m(¹³C) = 0.14303691.

1 percent of the solar radiation

Answer:

The empirical formula is =

The Valproic acid formula is =

Explanation:

Mass of the produced water = 0.166 g

Molar mass of water = 18 g/mol

The moles of are calculated as 0.166 g /18 g/mol = 0.00922 moles.

In 1 mole of water, there are 2 moles of hydrogen atoms.

Thus,

Moles of H = 2 x 0.00922 = 0.01844 moles

Each hydrogen atom's molar mass is 1.008 g/mol.

Hydrogen mass in the molecule = 0.01844 x 1.008 = 0.018588 g

Mass of produced carbon dioxide = 0.403 g

Molar mass of carbon dioxide = 44.01 g/mol

The moles of are calculated as 0.403 g  /44.01 g/mol = 0.009157 moles.

Each carbon atom's presence is 1 mole in 1 mole of carbon dioxide.

So,

Moles of C = 0.009157 moles

The molar mass of carbon is 12.0107 g/mol.

Carbon mass in molecule = 0.009157 x 12.0107 = 0.11 g

Since Valproic acid comprises only hydrogen, oxygen, and carbon, the oxygen mass in the sample = Total mass - Carbon mass  - Hydrogen mass.

The sample's overall mass = 0.165 g.

Oxygen mass in the sample = 0.165 - 0.11 - 0.018588 = 0.036412 g  

The molar mass of oxygen is 15.999 g/mol.

Moles of O  = 0.036412  / 15.999  = 0.002276 moles

Taking the simplest ratio for H, O, and C yields:

0.01844: 0.002276: 0.009157

= 8: 1: 4

The empirical formula becomes

While molecular formulas detail the precise count of atoms for each element, empirical formulas represent the simplest form or reduced ratio of these elements in the compound.

Consequently,  

The molecular mass equals n × Empirical mass.

Here, n is a positive integer from 1, 2, 3...

Empirical mass = 4×12 + 8×1 + 16 = 72 g/mol.

Molar mass = 144 g/mol.

Thus,  

The molecular mass = n × Empirical mass.

144 = n × 72

⇒ n = 2

The Valproic acid formula is =