Answer:
The mass percent of sulfur is 9.98%.
Explanation:
<em>The percentage of sulfur in coal can be determined by burning a sample of the solid and passing the resulting sulfur dioxide gas into a solution of hydrogen peroxide, which oxidizes it to sulfuric acid, and then titrating the acid.</em>
The corresponding balanced equations are:
S + O₂ ⇄ SO₂ [1]
SO₂ + H₂O₂ ⇄ H₂SO₄ [2]
H₂SO₄ + 2 NaOH ⇄ Na₂SO₄ + 2 H₂O [3]
First, we have to calculate how many moles of NaOH we have.
n = 0.114 mol/L × 0.441 L = 0.0502 mol
Then, we will use the following relations:
- According to [3], 2 moles of NaOH react with 1 mole of H₂SO₄
- According to [2], 1 mole of H₂SO₄ is produced per mole of SO₂
- According to [1], 1 mole of SO₂ is produced per mole of S
- The molar mass of S is 32.0 g/mol
Then, for 0.0502 moles of NaOH:
If there are 0.803 g of S in an 8.05 g sample, the mass percent of sulfur is:
Answer:
Nitrogen A would be more nucleophilicity (figure 1.)
Explanation:
In the <u>DMAP </u>molecule we will have 2 nitrogens label as "nitrogen A" and "nitrogen B". For nitrogen B we will have more<u> steric hindrance</u> due to the 2 methyls groups and the benzene ring. What will hinder the attack from this nitrogen (nitrogen B) to an <u>electrophile</u>. On the contrary, the attack of nitrogen A could easily occur.
Answer:
irreversible changes
Explanation:
Most chemical changes are permanent and cannot be reversed. That is because a chemical change involves changing the molecular composition which can't be reversed. A common example of a chemical change would be burning wood. The wood burning into ash is changing the molecular composition of the wood transforming it to ash. Now can ash be changed back into wood? No, it is a "irreversible change."
Hope this helps.
multimeter is an electronic instrument used to measure the three basic electrical characteristics: voltage, current and resistance. It has multiple functions and acts like ohmmeter, voltmeter and ammeter and also used for household wiring, electric motors, testing batteries and power supplies.