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mamaluj [8]
2 years ago
10

Molecules of SiO2 would have a mass of 12.40 g

Chemistry
1 answer:
creativ13 [48]2 years ago
7 0

Answer:

1.244x10^23 molecules

Explanation:

From Avogadro's hypothesis, 1mole of any substance contains 6.02x10^23 molecules.

This means that 1mole of SiO2 contains 6.02x10^23 molecules

1mole of SiO2 = 28 + (2x16) =28 +32 = 60g

If 1 mole(i.e 60) of SiO2 contains 6.02x10^23 molecules,

Therefore, 12.40g of SiO2 will contain = (12.40 x 6.02x10^23) / 60 = 1.244x10^23 molecules

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Which statement regarding serum magnesium (Mg ++) is true? (Select all that apply.) Alcohol-related diseases frequently cause lo
Elanso [62]

Answer:

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Alcohol-related diseases frequently cause low Mg+ levels.

- Mg+ deficiencies must be treated before potassium (K+) deficiencies.

- Mg+ deficiencies often result in low serum potassium (K+)

- Mg++ levels present similarly to calcium (Ca++) levels in the blood.

- Vomiting is not generally seen as a major cause of Mg+ loss

3 0
2 years ago
In 1-2 sentences, explain why weather can be predicted only as probable, not definite. (2 points) Plaese help me ​
anyanavicka [17]

Weather can be predicted only as probable, not definite because the daily weather conditions depends on winds and storms.

It is common observation that weather forecasts are often given as a probability and never in definite terms.

This is because, the weather condition at anytime depends on the temperature of the earth's atmosphere which causes air masses to move leading to wind.

The temperature of the earth's atmosphere changes frequently hence weather conditions also change frequently.

Learn more: brainly.com/question/21209813

8 0
1 year ago
Calculate the percent activity of the radioactive isotope strontium-89 remaining after 5 half-lives.
maria [59]
The answer to this question would be: 3.125%

Half-life is the time needed for a radioactive molecule to decay half of its mass. In this case, the strontium-89 is already gone past 5 half lives. Then, the percentage of the mass left after 5 half-lives should be:
100%*(1/2^5)= 100%/32=3..125%
5 0
1 year ago
Hydrogen peroxide, H2O2, is common in many households and is used as a bleaching agent. It usually comes in a dark, opaque bottl
sergij07 [2.7K]

Answer:

Hydrogen peroxide should be stored in

1) a cool environment

2) with amber bottles away from sunlight

3) with little drops of sodium phosphate

Explanation:

It has been confirmed that heat and light aids in the decomposition of hydrogen peroxide according to the equation; 2H2O2→2 H2O + O2.

This means that hydrogen peroxide must be stored in a cool place. This will reduce its rate of decomposition. Secondly, it should be stored in amber bottles away from light since light also aids in its decomposition.

Thirdly, drops of sodium phosphate may be added to prevent its catalytic decomposition during storage.

8 0
2 years ago
If 35.50 cm3 of a NaOH solution are required for the complete neutralization of a 25.00cm3 sample of 0.200mol dm-3 H2SO4, what i
Morgarella [4.7K]
In this question, you are given the NaOH volume but asked for concentration. 
Don't forget that for every 1 mol of NaOH there will be 1 mol OH- ion, but for every 1 mol of H2SO4 there will be 2 mol of H- ion.
To neutralize you need the same amount of OH- and H+, so the equation should be:

OH-= H+
<span>35.50cm3 * x*1= 25cm3* 0.2mol/dm3 *2
</span>x= 10/35.5 mol/dm3= 0.2816/dm3
6 0
2 years ago
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