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mihalych1998 [28]

3 years ago

7

On a cool morning, Uyen’s breath can form a cloud when she breathes out. Which changes of state are most responsible for Uyen se

eing her breath in this way?
melting
condensation
deposition
sublimation

2 answers:

Dima020 [189]3 years ago

8 0

Condensation because condensation is a process of freezing

sergiy2304 [10]3 years ago

7 0

The 2nd one is the correct answer

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Who was the scientist responsible for the discovery of the keystone species

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Answer:

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Explanation:

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How do you Calculate the molarity of 250 ml of solution in which 2.7 g of MgCl2 are dissolved

IRINA_888 [86]

Answer:

Molar mass of MgCl2 is 95 g/mol

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moles = mass given/ molar mass

= 2.7/95 = 0.028 mol

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molarity of MgCl2 = moles/volume

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2 years ago

What is the mass of CO2 lost at 20 min from the limestone sample?

harkovskaia [24]

Answer:

The mass, CO2 and CO3 from the limestone sample is discussed below in details.

Explanation:

(A) mass loss of sample of limestone after 20 min

= 0.8437g-0.5979g = 0.2458 g

From the given reaction of limestone, 2 mol of the sample gives 2 moles of CO 2.

Therefore

184.4 g ( molar mass of limestone) gives2× 44 g of carbon dioxide.

1 g of sample gives 88/184.4 g of carbon dioxide

Hence 0.2458 g sample gives

= 88/184.4 × 0.2458 g = 0.117 g carbon dioxide

(B) mole of CO 2 lost = weight/ molar mass

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(C). 1 mol of limestone contain 2 mol of carbonate ion

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Hence lost carbonate ion = 0.2458 g

(D) we know that

1 mol limestone contain 1mol CaCO 3

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8 0

3 years ago

How many hydrogen atoms are in 4.40 mol of ammonium sulfide

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The number of hydrogen atoms that are in 4.40 mol of ammonium sulfide is 2.12 x10^25 atoms

calculation
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moles is therefore= 4.40 x8= 35.2 moles

by use of Avogadro's law constant

that is 1mole = 6.02 x10^23 atoms
35.2 moles=?

by cross multiplication
{35.2 moles x 6.02 x10^23} /1 mole = 2.12 x10^25 atoms

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3 years ago

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katen-ka-za [31]

I wrote the answer on this paper and here is the calculations step by step

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