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valina [46]
3 years ago
11

Which of these is an element?

Chemistry
2 answers:
Yanka [14]3 years ago
6 0

Answer:

A.

Explanation:

The rest are molecules and/or compounds

just olya [345]3 years ago
3 0
B
Sksnksnsksksksksksksks
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What is the function of the cell membrane
enot [183]
It is supposed to protect the cell from it's surroundings, or from the outside.
8 0
3 years ago
13. A mixture of MgCO3 and MgCO3.3H2O has a mass of 3.883 g. After heating to drive off all the water the mass is 2.927 g. What
rjkz [21]

Answer:

63.05% of MgCO3.3H2O by mass

Explanation:

<em>of MgCO3.3H2O in the mixture?</em>

The difference in masses after heating the mixture = Mass of water. With the mass of water we can find its moles and the moles and mass of MgCO3.3H2O to find the mass percent as follows:

<em>Mass water:</em>

3.883g - 2.927g = 0.956g water

<em>Moles water -18.01g/mol-</em>

0.956g water * (1mol/18.01g) = 0.05308 moles H2O.

<em>Moles MgCO3.3H2O:</em>

0.05308 moles H2O * (1mol MgCO3.3H2O / 3mol H2O) =

0.01769 moles MgCO3.3H2O

<em>Mass MgCO3.3H2O -Molar mass: 138.3597g/mol-</em>

0.01769 moles MgCO3.3H2O * (138.3597g/mol) = 2.448g MgCO3.3H2O

<em>Mass percent:</em>

2.448g MgCO3.3H2O / 3.883g Mixture * 100 =

<h3>63.05% of MgCO3.3H2O by mass</h3>
6 0
3 years ago
A chemist has some 40% acid solution, some 60% acid solution, and a wholebunch of free time. How many liters of each should be u
TiliK225 [7]

Answer:

30 Liters of 40% acid solution and 10 L of 60% acid solution is needed.

Explanation:

Let volume of the 40% acid solution be x.

Let volume of the 60% acid solution be y.

Volume of solution formed after mixing both solution = 40 L

x + y = 40 L..[1]

Volume of acid 40% solution = 40% of x= 0.4x

Volume of acid 60% solution = 60% of y= 0.6y

Volume of acid formed = 45% of 40 L = \frac{45}{100}\times 40=18L

0.4x+0.6y=18 L..[2]

Solving [1] and [2]

x = 30 L  ,   y = 10 L

30 Liters of 40% acid solution and 10 L of 60% acid solution is needed.

8 0
3 years ago
How does the VSEPR theory explain molecular shape?
Advocard [28]

Answer:

D. Electron pairs repelling each other push atoms apart

Explanation:

Hope this helps :) I just got it wrong on ap3x so I'm sure this is right

3 0
3 years ago
Read 2 more answers
Q3. A bridge is built without expansion gaps.
marshall27 [118]

Answer:

Q3. A bridge is built without expansion gaps.

Explain what could happen to the bridge if the temperature became:

a) much hotter than the day it was built.

b) much colder than the day it was built.

P.s. (this is not a select option question, explain each according to the question)

5 0
4 years ago
Read 2 more answers
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