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1 year ago

What is the mass of 3.91 × 1024 molecules of seo2? the molar mass of seo2 is 110.96 g/mol?

Chemistry

2 answers:

frozen [14]1 year ago

8 0

Answer:

Mass of $3.91\times 10^{24}$ number of $SeO_{2}$ molecules is 720.3g

Explanation:

Mass of 1 mol of $SeO_{2}$ is 110.96 g

We know, 1 mol of molecule = $6.023\times 10^{23}$ number of molecules

So, mass of $6.023\times 10^{23}$ number of $SeO_{2}$ molecules is 110.96 g

Hence mass of $3.91\times 10^{24}$ number of $SeO_{2}$ molecules = $\frac{110.96\times 3.91\times 10^{24}}{6.023\times 10^{23}}g=720.3g$

3241004551 [841]1 year ago

4 0

The answer is 720.68, but to 3 sig. figs it would be 721. You get this by:

3.91x10^24 (1mol/ 6.02x10^3 molecules) (110.96/ 1mol)= 720.68

Hope that helps!

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A balance measures mass to 0.001 g. If you determine the mass of an object that weighs about 30 g, would you record the mass as

solong [7]

Answer:

The mass is recorded as 32.075 g

Explanation:

"The first digit of uncertainty is taken as the last significant digit", this is the rule for significant figures in the analysis. The balance measures the mass up to three decimal places, so it makes the most sense to note the whole figure.

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2 years ago

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A voltaic cell is constructed with two silver-silver chloride electrodes, where the half-reaction is AgCl (s) + e− → Ag (s) + Cl

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Answer : The cell emf for this cell is 0.118 V

Solution :

The half-cell reaction is:

$AgCl(s)+e^\rightarrow Ag(s)+Cl^-(aq)$

In this case, the cathode and anode both are same. So, $E^o_{cell}$ is equal to zero.

Now we have to calculate the cell emf.

Using Nernest equation :

$E_{cell}=E^o_{cell}-\frac{0.0592}{n}\log \frac{[Cl^{-}{diluted}]}{[Cl^{-}{concentrated}]}$

where,

n = number of electrons in oxidation-reduction reaction = 1

$E_{cell}$ = ?

$[Cl^{-}{diluted}]$ = 0.0222 M

$[Cl^{-}{concentrated}]$ = 2.22 M

Now put all the given values in the above equation, we get:

$E_{cell}=0-\frac{0.0592}{1}\log \frac{0.0222M}{2.22M}$

$E_{cell}=0.118V$

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A sample of pure iron has a mass of 5.00 g. Calculate its volume.

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It's volume is 0.48 cm3Specific

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2 years ago

What volume will 6.745g of neon gas occupy at standard temp and pressure?

Thepotemich [5.8K]

First, multiply the mass by the molar mass of neon to find out how many moles of neon there are. Then, multiply by 22.4 to find out how many liters there are.

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2 years ago

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A compound of barium and oxygen was dissolved in hydrochloric acid to give a solution of barium ion, which was then precipitated

n200080 [17]

Answer:

The empiricial formula of the compound is BaO2

Explanation:

Step 1: Data given

Barium and oxygen dissolved in hydrochloric acid gives a solution of barium ion. This was precipitated with an excess of potassium chromate and gives barium chromate.

The original compound weighs 1.345g and gives 2.012g of BaCrO4

Step 2: Calculate moles of BaCrO4

moles of BaCrO4 = mass of BaCrO4 / molar mass of BaCrO4

moles of BaCrO4 = 2.012g / 253.37 g/mol = 0.0079 moles

Step 3: Calculate moles of Ba

Mole ratio for Ba and BaCrO4 is 1:1 so this means for 0.0079 moles of BaCrO4, there are 0.0079 moles of Ba-ion

Step 4: Calculate mass of Ba-ion

Mass of Ba = Moles of Ba / Molar mass of Ba

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Step 5: Mass of oxygen

Since the original compound has barium and oxygen, the mass of oxygen is the difference between the original mass and the mass of the Ba-ion

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Step 6: Calculate moles of Oxygen

moles oxygen = mass of oxygen / Molar mass of oxygen

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We divide the number of moles by the smallest number of moles which is 0.0079

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This gives us the empirical formula of BaO2 for this compound

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