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2 years ago

Convert 4.92 L of hydrogen at STP to moles.

2 answers:

5 0

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$\sf C) \: 0.220 \: mol \: H_2$

Explanation:

1 mol = 22.4 litres

4.92 = how many moles?

$\sf \implies \frac{4.92}{22.4} \\ \\ \sf \implies 0.2196 \\ \\ \sf \implies 0.220 \: mol \: H_2$

patriot [66]2 years ago

3 0

Answer:

c. 0.220 mol H₂

Explanation:

No. of moles

Volume present / Volume at STP
4.92 L / 22.4 L
0.220 mol H₂

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Information-

tekilochka [14]

Answer:

So first thing to do in these types of problems is write out your chemical reaction and balance it:

Mg + O2 --> MgO

Then you need to start thinking about moles of Magnesium for moles of Magnesium Oxide. Based on the above equation 1 mole of Magnesium is needed to make one mole of Magnesium Oxide.

To get moles of magnesium you need to take the grams you started with (.418) and convert to moles by dividing by molecular weight of Mg (24.305), this gives you .0172 moles of Mg.

The theoretical yield would be the assumption that 100% of the magnesium will be converted into Magnesium Oxide, so you would get, based on the first equation, .0172 mol of MgO. Multiplying this by the molecular weight of MgO (24.305+16) gives us .693 g of MgO.

The percent yield is what you actually got in the experiment, and for this you subtract off the total mass from the crucible mass, or 27.374 - 26.687, which gives .66 g of MgO obtained.

Percent yield is acutal/theoretical, .66/.693, or 95.24%.

I'll let you do the same for the second trial, and average percent yield is just an average of the two trials percent yield.

Hope this helps.

6 0

3 years ago

- How many grams are in 4.6 x 1016 molecules of phosphorus trichloride (PCI)?

MariettaO [177]

Answer:

0.0000101 grams.

Explanation:

First of all, use Avogadro's number to convert from molecules to moles.

Avogadro's number is 6.02 x 10^23.

Second of all, to convert from moles to grams, find the substance formula of phosphorus trichloride. After finding the substance formula, then find the molar mass of phosphorus trichloride.

Phosphorus trichloride is PCl3

Now find the molar mass of PCl3

P = 31.0 amu

Cl = 35.5 amu

They are three chlorine atoms and one phosphorus atom. So you do this.

31.0(1) + 35.5(3) = 137.5 g/mol

Now use dimensional analysis to show your work

4.6 x 10^16 grams of PCl3 * 1 mol/ 6.02 x 10^23 * 137.5 g/mol / 1 mol

The grams and the moles cancel out.

So now do [(4.6 x 10^16) / (6.02 x 10^23)] x 137.5

and you will get 0.000010507

4.6 has the fewest digits which is 2.

So use sig figs and the answer rounds to the nearest millionths.

0.000010507 rounds to 0.0000101

So the final answer is 0.0000101 grams(don't forget the units)

Hope it helped!

4 0

3 years ago

The continents are made up of mostly what type of rock

raketka [301]

Granite and basalt is the answer
hope it helps

3 0

3 years ago

Read 2 more answers

__ P4(s) + __ O2(g) → __ P4O10(s) To balance this reaction equation, first write correct formulas for the reactants and products

Vedmedyk [2.9K]

Answer:

P4(s) + 5 O2 (g)→ P4O10

Explanation:

If we desire to write a balanced chemical reaction equation, the rule of thumb is simple; the number of atoms of each element on the right hand side of the reaction equation must be the same as the number of atoms of the same element on the left hand side of the reaction equation. Once this condition is satisfied, the reaction equation is said to be balanced.

As we can see, we need one mole of P4 and five moles of O2 to produce one mole of P4O10.

8 0

4 years ago

When two ionic compounds are dissolved in water, a double replacement reaction can... Group of answer choices occur if two of th

sergey [27]

Answer:

occur if two of the ions form an insoluble ionic compound, which precipitates out of solution

Explanation:

When two ionic compounds are dissolved in water, a double replacement reaction takes place if two of the ions form an insoluble ionic compound, which precipitates out of solution. In double displacement reaction ions switch partners. And hence, produce an insoluble precipitate.

5 0

3 years ago