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Assoli18 [71]
3 years ago
7

A chemist weighed out 70.8 g of magnesium. Calculate the number of moles of magnesium she weighed out. Round your answer to sign

ificant digits.

Chemistry
2 answers:
solniwko [45]3 years ago
8 0

Answer:

2.91 grams of Magnesium

Explanation:

I put a picture . I used the molar mass of magnesium which can be calculated from the periodic table or simply google it. :) I hope it helps - Enrique

AlekseyPX3 years ago
4 0
You first take the weighed out amount of magnesium then you divide by the actual mass of magnesium 24.305 g. 70.8/24.305 = 2.912980868134129. Then you multiply by Avagadros number 6.02x10^23. 2.9129 x 6.02x10^23 = 1.753614482617^24. Then round it to 1.75^24 moles of magnesium
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How many moles of helium are needed to fill a balloon to a volume of 5.3 L at 22 ℃ and 632 mmHg?
son4ous [18]

Answer:

0.18 moles

Explanation:

Applying,

PV = nRT................... Equation 1

Where P = pressure, V = volume, n = number of moles, R = molar gas constant, T = temperature.

make n the subject of the equation

n = PV/RT............... Equation 2

Given: V = 5.3 L, T = 22 °C = (22+272) K = 295 K, P = 632 mmHg = (0.00131579×632) = 0.8316 atm,  R = 0.083 L.atm/K.mol

Substitute these values into equation 2

n = (0.8316×5.3)/(0.083×295)

n = 0.18 moles

6 0
3 years ago
How many miles of C atoms are present in a sample of 3.85x1024 C atoms?
alekssr [168]
Answer:
number of moles = 6.393 moles

Explanation:
One mole of any substance contains Avogadro's number (6.022 * 10^23) of atoms. 
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1 mole ......................> 6.022 * 10^23
?? moles ..................> 3.85 * 10^24
number of moles = (3.85 * 10^24 *1) / (6.022 * 10^23)
number of moles = 6.393 moles

Hope this helps :)
8 0
2 years ago
An astronaut is free-floating in space near a space station and it is not tethered to anything. He has some tools and a fire ext
worty [1.4K]

Hey there

the answers are

A.

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7 0
3 years ago
Read 2 more answers
Which statement below best describes mutations?
Studentka2010 [4]

Answer:

C. Mutations are a change in DNA or a chromosome and can be helpful, harmful or may have no affect.

Explanation:

  • Mutations are spontaneous random changes that occurs in the genetic make up of an organisms. Mutations are rare and their rate of occurrence is random.
  • Mutations may occur on the gene level known as gene mutations or at chromosome levels called chromosomal mutations.
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8 0
3 years ago
15.0 g of Fe and 25.0 g of sand are added to 250.0 g of water. a. Determine the percent mass of Fe, sand, and water in the mixtu
lana [24]

Answer:

A. percentage mass of iron = 5.17%

percentage mass of sand  = 8.62%

percentage mass of water = 86.205%

B. (Iron + sand + water) -------> ( iron + sand) ------> sand

C. The step of separation of iron and sand

Explanation:

A. Percentage mass of the mixtures:

Total mass of mixture = (15.0 + 25.0 + 250.0) g =290.0 g

percentage mass of iron = 15/290 * 100% = 5.17%

percentage mass of sand = 25/290 * 100% = 8.62%

percentage mass of water = 250/290 * 100% = 86.205%

B. Flow chart of separation procedure

(Iron + sand + water) -------> separation by filtration using filter paper and funnel to remove water --------> ( iron + sand) -----------> separation using magnet to remove iron ------> sand

C. The step of separation of iron and sand by magnetization of iron will have the highest amount of error because during the process, some iron particles may not readily be attracted to the magnet as they may have become interlaced in-between sand grains. Also, some sand particle may also be attracted to the magnet as they are are borne on iron particles.

5 0
2 years ago
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