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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
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How many Liters of 0.50M HCl are needed to neutralize 0.050L of 0.101M Ba(OH)2?
Aleksandr-060686 [28]

Answer:

V_{HCl}=5.05x10^{-3}L

Explanation:

Hello,

In this case, since hydrochloric acid and barium hydroxide are in a 2:1 molar ratio, for the neutralization, the following moles equality must be obeyed:

2*n_{HCl}=n_{Ba(OH)_2}

In such a way, in terms of molarities and volumes, we can compute the required volume of hydrochloric acid as shown below:

2*M_{HCl}V_{HCl}=M_{Ba(OH)_2}V_{Ba(OH)_2}\\\\V_{HCl}=\frac{M_{Ba(OH)_2}V_{Ba(OH)_2}}{2M_{HCl}} =\frac{0.101M*0.050L}{2*0.50M} \\\\V_{HCl}=5.05x10^{-3}L

Besr regards.

8 0
3 years ago
Read 2 more answers
What is the correct description of the components of an ATP molecule?
frosja888 [35]
It's adenosine triphosphate !

it has Penrose sugar and phosphate as backbone !
and nitrogenous base ... adenine.... in the middle !
4 0
3 years ago
The weight of the body in the air is .... the weight of the submerged body
stira [4]

Answer:

the correct answer is option 'b': More than

Explanation:

The 2 situations are represented in the attached figures below

When an object is placed in air it is acted upon by force of gravity of earth which is measured as weight of the object.

While as when any object is submerged partially or completely in any fluid the fluid exerts a force in upward direction and this force is known as force of buoyancy and it's magnitude is given by Archimedes law as equal to the weight of the fluid that the body displaces, hence the effective force in the downward direction direction thus the apparent weight of the object in water decreases.

4 0
3 years ago
Given the equation: HCl + Na2SO4 → NaCl + H2SO4, if you start with 8 moles of hydrochloric acid, how many grams of sulfuric acid
Simora [160]

Answer:

392g sulfuric acid are produced

Explanation:

Based on the balanced equation:

2HCl + Na2SO4 → 2NaCl + H2SO4

<em>2 moles of HCl produce 1 mole of sulfuric acid</em>

<em />

To solve the problem we need to find the moles of sulfuric acid produced based on the chemical equation. Then, using its molar mass -<em>Molar mass H2SO4 = 98g/mol- </em>we can find the mass of sulfuric acid produced:

<em>Moles sulfuric acid:</em>

8mol HCl * (1mol H2SO4 / 2mol HCl) = 4 mol H2SO4

<em>Mass sulfuric acid:</em>

4mol H2SO4 * (98g / mol) =

392g sulfuric acid are produced

4 0
3 years ago
What is the best definition for the atomic number in an element
arlik [135]
The atomic number in an element is usually how many protons the element has. For example, Hydrogen has a 1 on top of the H (on the periodic table), therefore, Hydrogen has 1 proton. Oxygen has an 8 on top of the O (on the periodic table) so therefore, Oxygen has 8 protons.
7 0
3 years ago
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