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Alexxx [7]
4 years ago
11

Naturally occurring element X exists in three isotopic forms: X-28 (27.979 u, 77.11% abundance), X-29 (28.976 u, 8.00% abundance

), and X-30 (29.974 u, 14.89% abundance). Calculate the atomic weight of X.
Chemistry
1 answer:
slava [35]4 years ago
7 0

Answer:

The atomic weight of X is 28.356 amu

Explanation:

Step 1: Data given

X-28 has an isotopic mass of 27.979 u and an baundance of 77.11%

X-29 has an isotopic mass of 28.976 u and an baundance of 8.00 %

X-30 has an isotopic mass of 29.974 u and an baundance of 14.89 %

Step 2:  Calculate the atomic weight of X.

Atomic weight of X = 27.979 * 0.7711 + 0.28.976 * 0.08 + 29.974 *0.1489

Atomic weight of X = 28.356 amu

The atomic weight of X is 28.356 amu

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If a man has a mass of 83 kilograms on Earth, what will the force of gravity on his body be on the moon?
VladimirAG [237]
The answer is (A.) 135.6 N

————

Here is the formula you will need to answer the question.

Formula:
Force(N) = Mass(kg) x Acceleration(m/s²)
or... F(N) = m(kg) x a(m/s²)

————

We need to be certain of the information presented. The problem says the man has a "Mass" of 83 kilograms on Earth. If a man has a Mass of 83 kilograms on Earth, he has a mass of 83 kilograms everywhere. The mass for this problem (even on the moon) is 83.

Mass(kg): 83

————

To find the acceleration of object on other planets, moons, ect, you'll need to search the internet or ask a teacher. There are ways to calculate this, but the problem didn't supply the necessary information to do so.

Acceleration: 1.625 m/s²

————

Now just plug the information into the formula.

F(N) = m(kg) x a(m/s²)

N = 83 x 1.625
N= 135.875

When considering that there could be a slighty more accurate number for acceleration, it can be concluded that the best answer is (A.)

3 0
4 years ago
Zinc Mass If a 1.85 g mass of zinc produces 475 mL of gas and your balloon weighs 0.580 g and the room temperature is 21.5°C. Ca
Alexus [3.1K]
The weight of the balloon is irrelevant because it is the gas that lifts it in the air. We are already given with the required volume, so we use this instead. The atomic weight of zinc is 65.38 g/mol. Assuming ideal gas behavior,

PV=nRT
P(475 mL)(1 L/1000 mL) = (1.85/65.38)(0.0821 L·atm/mol·K)(21.5 + 273)
P = 1.44 atm

Then, we use this pressure and the volume to find the moles of zinc.

(1.44 atm)(475 mL+1 mL)(1 L/1000 mL) = n(0.0821 L·atm/mol·K)(21.5 + 273)
Solving for n,
<em>n = 0.02836 moles of zinc</em>
3 0
4 years ago
What is the molar mass of a gas with a density of 3.50 g/L at a
Kruka [31]

Answer:

  • <u>104 g/mol</u>

Explanation:

Use the ideal gas equation:

      pV=nRT

Where:

  • p is pressure: 0.950atm
  • V is volume: unknown
  • n is number of moles: unknown
  • R is the universal constat of gases: 0.08206 atm.liter/ (K.mol)
  • T is the absolute temperature: 345K

Use the <em>molar mass</em> of the gas to include the density in the formula:

  • molar mass = mass in grams / number of moles

  • ⇒ mass in grams = number of moles × molar mass

  • density = mass in grams / volume

  • ⇒ density = number of moles × molar mass / volume

  • density = (n/V) × molar mass

  • ⇒ n/V = density / molar mass

Clear n/V from the gas ideal equation and subsittute with density/molar mass:

  • n/V = p/(RT)
  • density / molar mass = n/V
  • density/molar mass = p/(RT)
  • molar mass = density × RT / p

Now you can subsitute the data:

molar mass = (3.50g/liter) × 0.08206 atm.liter/(K.mol) × 345K / 0.950 atm

  • molar mass = 104.3 g/mol

  • Round to the nearest whole number: 104g/mol ← answer
3 0
3 years ago
Assuming the boiling point increased by 2 °C, what is the approximate molality of NaCl when the video ends? Kbp(water) = 0.512
makkiz [27]

Answer : The molality of NaCl is, 1.95 mol/kg

Explanation :

Formula used for Elevation in boiling point :

\Delta T_b=i\times k_b\times m

where,

\Delta T_b = change in boiling point = 2^oC

k_b = boiling point constant  for water = 0.512^oC/m

m = molality

i = Van't Hoff factor = 2 (for electrolyte)

The dissociation NaCl will be,

NaCl\rightarrow Na^++Cl^{-}

So, Van't Hoff factor = Number of solute particles = Na^++Cl^{-} = 1 + 1 = 2

Now put all the given values in the above formula, we get:

2^oC=2\times (0.512^oC/m)\times m

m=1.95mol/kg

Therefore, the molality of NaCl is, 1.95 mol/kg

6 0
3 years ago
What happens when two objects when they are brought closer together The mass of both objects decrease The mass of both objects i
Maurinko [17]

Answer:

The correct option is

The gravitational force between them increases

Explanation:

According to Newton's law of universal gravitation states that the force of attraction between two bodies is directly proportional to the product of the masses of the bodies and inversely proportional to the square of the distance of their centers from each other.

The formula for universal gravitation is given as follows;

F_{1} = F_{2} =G \times \dfrac{m_{1}  \times m_{2}}{r^{2}}

Where;

F₁, and F₂ = The gravitational forces of attraction on each mass

G = The gravitational constant

m₁ = The mass of one body

m₂ = The mass of the body

r = The distance between the centers of the two bodies

Therefore, the gravitational force of attraction on each object is inversely proportional to the as the distance between the centers of the two bodies

When the distance between the centers of the two bodies decreases, the two objects are brought closer together, the gravitational force of attraction between them increases.

8 0
3 years ago
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