How many atoms are there in 90.2 grams of selenium?

1 answer:

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

A gas at 1.2 atm has a

Papessa [141]

Answer:

1.26 mole

Explanation:

Using ideal gas law

PV=nRT

R= 0.08206

T=273+87=360

1.2×31=n×0.08206×360

37.2 =n × 29.54

n= 1.26 mole

8 0

3 years ago

Select the correct answer.

Fittoniya [83]

Answer:

subscribe to me on you-tube for brainliest custom link since u cant do a you-tube link :/

https://screenshare.host/B7N8NT

Explanation:

7 0

2 years ago

Determine if these molecules and ion are polar.

Colt1911 [192]

Answer:

a. Polar

b. Polar

c. Non-polar

d. Non-polar

Explanation:

a. $H_3O^+$ , hydronium cation contains a positive charge. Just as any other ion, it is polar, as it has a net charge.

b. $H_2S$ has the same shape as water. There are two lone pairs on sulfur atom which produce an overall dipole moment in this molecule, the bent structure is polar.

c. $PCl_5$ is non-polar, as the central atom, phosphorus, doesn't contain any lone pairs, all the dipole moments cancel out: two dipole moments in the vertical plane, P-Cl, and three P-Cl dipoles in the horizontal plane within a trigonal bipyramidal shape.

d. $CF_4$ is non-polar, since it's a tetrahedral molecule with no lone pairs on carbon atom, all four C-F dipole moments cancel out to yield a net 0 dipole moment.