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4 years ago

Why is the average atomic mass used when calculating grams of a substance?

Chemistry

2 answers:

GarryVolchara [31]4 years ago

6 0

The elements in the substance are mixtures of their isotopes.

galina1969 [7]4 years ago

4 0

The average atomic mass includes all of the isotopes of that atom which exist in nature. Almost all elements have at least two isotopes which naturally occur.
Recall that isotopes are atoms with the same atomic number (protons), but a different number of neutrons. Since neutrons contribute the same amount of mass as a proton (1 amu), differing numbers of neutrons will change the mass of the atoms.

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34.1 mg NaCl in 117.3 mL of solution

Solnce55 [7]

The molarity of the solution will be 4.97 M.

<h3>What is molarity?</h3>

It is the number of moles of solutes per 1 liter of solvent or solution.

Mole of 34.1 g NaCl = 34.1/58.44 = 0.5835 mol

117.3 mL = 117.3/1000 = 0.1173 L

Molarity of the solution = 0.5835/0.1173 = 4.97 M

More on molarity can be found here: brainly.com/question/2817451

#SPJ1

6 0

2 years ago

The heat capacity of water is 1cal degree'g1 (1 calorie per degree centigrade, per gram). You are given 1 gallon of water at 25

sdas [7]

Answer:

The heat needed to boil 1 gallon of water is 81,490.62 Joules.

Explanation:

$Q=mc\Delta T$

Where:

Q = heat absorbed or heat lost

c = specific heat of substance

m = Mass of the substance

ΔT = change in temperature of the substance

We have :

Volume of water = V = 1 gal = 4546.09 mL

Density of water , d= 1 g/mL

mass of water = m = d × V = 1g/mL × 4546.09 mL = 4546.09 g

Specific heat of water = c = 1 Cal/g°C

ΔT = 100°C - 25°C = 75 °C

9 (boiling pint of water is 100°C)

Heat absorbed by the water to make it boil:

$Q= 4546.09 g\times 1 Cal/g^oC\times 75^oC=340,956.75 Cal$

1 calorie = 4.184 J

$Q=\frac{340,956.75}{4.184} J = 81,490.62 J$

The heat needed to boil 1 gallon of water is 81,490.62 Joules.

5 0

3 years ago

4. Evaluate the information contained in this calculation and complete the

Neporo4naja [7]

Since you did not give a calculation, I will just give an example. Suppose that you are to burn 5 kg of methane (CH4) from 0 to 10°C. The specific heat capacity of methane is 4.475 kJ/kg-K.

H = mCpT

H = (5kg)( 4.475 kJ/kg-K)(10-0)

H = 223.75 kJ

Because the enthalpy is positive in value, methane takes in heat.

7 0

4 years ago

A 33.6 mL solution of KCl has a mass of 27.29 g. After evaporating to dryness, the dry salt residues has a mass of 6.31 g. Calcu

bixtya [17]

For the molarity and the percentage of the mass of kcl are mathematically given as

%m/m = 23.1%, molarity = 3.38M

<h3>What is the molarity?</h3>

Generally, the equation for the percentage of the mass of kcl is mathematically given as

(mass of kcl/mass of solution)x 100

therefore

%m/m = (6.31/27.29)x100

%m/m = 23.1%

The molarity

(no of mol/ vol of sol)

molarity = 0.0846mol/0.0250 L

molarity = 3.38M

In conclusion, the molarity is given as

molarity = 3.38M