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2 years ago

an element has atomic number 10 and an atomic mass of 20. how many neutrons are in the atom of this element

Chemistry

2 answers:

Flura [38]2 years ago

6 0

Hey there!

n = A - Z

n = 20 - 10

n = 10

11111nata11111 [884]2 years ago

5 0

Answer:

There are 10 neutrons in this atom of an element.

Explanation:

Atomic mass of an element = 20

Atomic mass number is the sum of number of protons and neutrons that are present in an atom.

Atomic Mass number = Number of protons + Number of neutrons

Atomic number of an element = 10

Atomic number is the number of protons or number of electrons that are present in an atom.

Atomic number = Number of electrons = Number of protons

Number of protons = 10

Atomic Mass number = Number of protons + Number of neutrons

20 = 10 + Number of neutrons

Number of neutrons = 10

There are 10 neutrons in this atom of an element.

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What ion is at a higher concentration in the extracellular fluid than in the intracellular fluid?

Phoenix [80]

There are two types of fluid in the body extracellular fluid and intracellular fluid (ECF and ICF), together they are account for total body water.
The Sodium (Na+) ion is at higher concentration in the extracellular fluid than in the intracellular fluid. The function of extracellular fluid is that it provide cells to watery environment so that they can easily live and perform their function.

8 0

2 years ago

ASAPPP. Describe how you could determine the specific heat of a sample of a solid substance. You may

Allushta [10]

Answer:

I would use calorimetric to determine the specific heat and I would measure the mass of a sample

Explanation:

I would use calorimetry to determine the specific heat.

I would measure the mass of a sample of the substance.

I would heat the substance to a known temperature.

I would place the heated substance into a coffee-cup calorimeter containing a known mass of water with a known initial temperature.

I would wait for the temperature to equilibrate, then calculate temperature change.

I would use the temperature change of water to determine the amount of energy absorbed.

I would use the amount of energy lost by substance, mass, and temperature change to calculate specific heat.

8 0

2 years ago

What is the molarity (M) of the following solutions?

Dennis_Churaev [7]

Answer:

The molarity (M) of the following solutions are :

A. M = 0.88 M

B. M = 0.76 M

Explanation:

A. Molarity (M) of 19.2 g of Al(OH)3 dissolved in water to make 280 mL of solution.

Molar mass of Al(OH)3 = Mass of Al + 3(mass of O + mass of H)

= 27 + 3(16 + 1)

= 27 + 3(17) = 27 + 51

= 78 g/mole

$Al(OH)_3$ = 78 g/mole

Given mass= 19.2 g/mole

$Mole = \frac{Given\ mass}{Molar\ mass}$

$Mole = \frac{19.2}{78}$

Moles = 0.246

$Molarity = \frac{Moles\ of\ solute}{Volume\ of\ solution(L)}$

Volume = 280 mL = 0.280 L

$Molarity = \frac{0.246}{0.280)}$

Molarity = 0.879 M

Molarity = 0.88 M

B .The molarity (M) of a 2.6 L solution made with 235.9 g of KBr

Molar mass of KBr = 119 g/mole

Given mass = 235.9 g

$Mole = \frac{235.9}{119}$

Moles = 1.98

Volume = 2.6 L

$Molarity = \frac{Moles\ of\ solute}{Volume\ of\ solution(L)}$

$Molarity = \frac{1.98}{2.6)}$

Molarity = 0.762 M

Molarity = 0.76 M

4 0

2 years ago

A sample of helium gas initially at 37.0°C, 785 torr and 2.00 L was heated to 58.0°C while the volume expanded to 3.24 L. What i

spayn [35]

Answer:

0.681 atm

Explanation:

To solve this problem, we make use of the General gas equation.

Given:

P1 = 785 torr

V1 = 2L

T1 = 37= 37 + 273.15 = 310.15K

P2 = ?

V2 = 3.24L

T2 = 58 = 58+273.15 = 331.15K

P1V1/T1 = P2V2/T2

Now, making P2 the subject of the formula,

P2 = P1V1T2/T1V2

P2 = [785 * 2 * 331.15]/[310.15 * 3.24]

P2 = 515.715 Torr

We convert this to atm: 1 torr = 0.00132 atm

515.715 Torr = 515.715 * 0.00132 = 0.681 atm

8 0

3 years ago

What volume (L) of 0.250 M HNO3 is required to neutralize a solution prepared by dissolving 17.5 g of NaOH in 350 mL of water ?

IRINA_888 [86]

<h3>Answer:</h3>

1.75 L HNO₃

<h3>Explanation:</h3>

We are given;

Molarity of HNO₃ as 0.250 M

Mass of NaOH as 17.5 g

Volume of NaOH = 350 mL

We are required to calculate the volume of 0.250 M

We are going to first write the balanced reaction:

NaOH(aq) + HNO₃(aq) → NaNO₃(aq) + H₂O(l)

Then, we calculate the number of moles of NaOH

Moles = Mass ÷ Molar mass

Molar mass of NaOH = 39.997 g/mol

= 17.5 g ÷ 39.997 g/mol

= 0.4375 moles

We can now calculate the number of moles of HNO₃ using the mole ratio from the equation;

Mole ratio of NaOH to HNO₃ is 1 : 1

Therefore, if moles of NaOH are 0.4375 moles then;

Moles of HNO₃ will also be 0.4375 moles

We can now calculate the volume of HNO₃

Morality = Number of moles ÷ Volume

Thus;

Volume = Number of moles ÷ Molarity

= 0.4375 moles ÷ 0.250 M

= 1.75 L

Therefore, the volume of HNO₃ is 1.75 L

5 0

3 years ago