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shtirl [24]
3 years ago
12

How many atoms are there in 90.2 grams of selenium?

Chemistry
1 answer:
Neko [114]3 years ago
4 0
First calculate the moles of selenium by multiplying the mass x molar mass
90.2 × 78.96 = 7122.2 moles

Number of moles multiplied by avogadros number gives number of atoms
7122.2 × 6.022 × 10^{23} = 4.289×10^{27} atoms
You might be interested in
What is the difference in uniformity between heterogeneous and homogeneous mixtures?
Aneli [31]

Answer:

The correct answer according to the uniformity the difference is whether you can distinguish more than one part in the mixture.

Explanation:

A homogeneous mixture is one in which with the naked eye or with a microscope no different parts can be distinguished. Its composition and properties are the same at all points, the substance is uniform.

In a heterogeneous mixture, we can observe different parts. Its composition is variable.  It can be broken down into simpler substances by physical processes. The substance, in this case, is not uniform.

Have a nice day!

4 0
3 years ago
Certain compound contains 7.3% carbon, 4.5% hydrogen, 36.4% oxygen, and 31.8% nitrogen. It’s reality molecular mass is 176.0. Fi
erastovalidia [21]

Answer:

The answer to your question is:

Explanation:

Data

carbon        7.3%          =     7.3g

hydrogen    4.5%         =      4.5g

oxygen       36.4%         =     36.4 g

nitrogen     31.8%         =     31.8 g

Now

For carbon

                    12 g --------------------1 mol

                    7.3 g     -------------     x

                       x = 7.3/12 = 0.608 mol

For hydrogen

                 1 g   --------------------  1 mol

                 4.5 g  ------------------    x

                   x = 4.5 mol

For oxygen

             16 g ------------------- 1 mol

             36.4 g ----------------    x

             x = 2.28 mol

For nitrogen

              14 g   ----------------   1 mol

              31.8 g ---------------    x

             x = 2.27 mol

Now divide by the lowest result, the is 0.608 from carbon

carbon              0.608/0.608 = 1

hydrogen           4.5/ 0.608 = 7.4

oxygen              2.28/0.608 = 3.75

nitrogen             2.27/0.608 = 3.73

Empirical formula = CH₇O₄N₄

     

6 0
2 years ago
Write the chemical reaction for  ammonia in water
Otrada [13]
NH3 + H2O -> NH4+ + OH-  is the answer I think I just did this in class today

6 0
3 years ago
Density is given in ____. a. Pa/cm3 c. g/s2 b. N/m2 d. g/cm3 Please select the best answer from the choices provided A B C D
Ray Of Light [21]
Density is given in Mass/Volume so the answer is D
7 0
3 years ago
Read 2 more answers
A 25.0 mL sample of sulfuric acid is completely neutralized by adding 32.8 mL of 0.116 mol/L ammonia solution. Ammonium sulfate
Paul [167]

Answer:

0.08 mol L-1

Explanation:

Sulfuric acid Formula: H2SO4

Ammonia Formula: NH3

Ammonium sulfate Formula: (NH₄)₂SO₄

H2SO4 + 2NH3 = 2NH4+ + SO4 2-

H2SO4 + 2NH3 = (NH₄)₂SO₄

H2SO4 = (1/2)x (32.8 x 10^-3 L x 0.116 mol L-1)/25 x 10^-3 L

= 0.08 mol L-1

7 0
2 years ago
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