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tensa zangetsu [6.8K]
3 years ago
11

How many neutrons of atomic mass is 31 and atomic number is 12

Chemistry
1 answer:
kogti [31]3 years ago
3 0

▪▪▪▪▪▪▪▪▪▪▪▪▪  {\huge\mathfrak{Answer}}▪▪▪▪▪▪▪▪▪▪▪▪▪▪

As we know, Number of protons = Atomic Number

So,

  • Number of protons = 12

And, Atomic mass = Number of protons + Number of Neutrons (N)

therefore ~

  • 31 = 12 + N

  • N = 31 - 12

  • N = 19

Number of Neutrons = 19

You might be interested in
Aqueous concentrated nitric acid is 69% hno3 by weight and has a density of 1.42 g/ml.
OleMash [197]

Answer: -

15.55 M

35.325 molal

Explanation: -

Let the volume of the solution be 1000 mL.

Density of nitric acid = 1.42 g/ mL

Total Mass of nitric acid Solution = Volume of nitric acid x Density of nitric acid

= 1000 mL x 1.42 g/ mL

= 1420 g.

Percentage of HNO₃ = 69%

Amount of HNO₃ = \frac{69} {100} x 1420 g

= 979.8 g

Molar mass of HNO₃ = 1 x 1 + 14 x 1 + 16 x 3 = 63 g /mol

Number of moles of HNO₃ = \frac{979.8 g}{63 g/ mol}

= 15.55 mol

Molarity is defined as number of moles per 1000 mL

We had taken 1000 mL as volume and found it to contain 15.55 moles.

Molarity of HNO₃ = 15.55 M

Mass of water = Total mass of nitric acid solution - mass of nitric acid

= 1420 - 979.8

= 440.2 g

So we see that 440.2 g of water contains 15.55 moles of HNO₃

Molality is defined as number of moles of HNO₃ present per 1000 g of water.

Molality of HNO₃ = \frac{15.55 x 1000}{440.2}

= 35.325 molal

3 0
3 years ago
A gas has a volume of 6.35 L at 88.6 kPa. What will be the volume at standard pressure? Standard Pressure = 101.3 kPa
alukav5142 [94]

Answer:

5.55 L

Explanation:

This excersise can be solved by the Boyle's law.

This law for gases states that the pressure of a gas in a vessel is inversely proportional to the volume of the vessel.

P₁ . V₁  = P₂ . V₂

The law comes from the Ideal Gases Law, in the first term.

P . V = n . R . T  In this case, n . R . T are all constant.

6.35 L . 88.6 kPa = 101.3 kPa . V₂

V₂ = (6.35 L . 88.6 kPa) / 101.3 kPa

V₂ = 5.55 L

It is inversely proportional because, as it happened in this case, pressure was increased, therefore volume decreased.

5 0
3 years ago
Please help me l don’t understand please !!!!!!
garik1379 [7]

Answer: C

Explanation:

he never had evidence in the first place that was nearly enough.

7 0
3 years ago
if we add mass to a paper airplane then the distance of the plane flies will increase or decrease why?
Ann [662]
It matters to the aerodynamics of it because sometimes it's good to have the weight but only if it can take it.
8 0
3 years ago
The compound methylamine, CH3NH2, is a weak base when dissolved in water. Write the Kb expression for the weak base equilibrium
Veronika [31]

Answer:

Kb = [CH₃NH₃⁺] × [OH⁻] / [CH₃NH₂]

Explanation:

According to Brönsted-Lowry acid-base theory:

  • An acid is a substance that donates H⁺.
  • A base is a substance that accepts H⁺.

When methylamine reacts with water, it behaves as a Brönsted-Lowry base, according to the following reaction.

CH₃NH₂(aq) + H₂O(l) ⇄ CH₃NH₃⁺(aq) + OH⁻(aq)

The basic equilibrium constant (Kb) is:

Kb = [CH₃NH₃⁺] × [OH⁻] / [CH₃NH₂]

3 0
3 years ago
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