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worty [1.4K]
2 years ago
12

Which of the following is the fundamental element found in all living organisms? A-iron B-carbon C-calcium D-magnesium

Chemistry
2 answers:
V125BC [204]2 years ago
8 0

Answer:

For me

Explanation:

it's carbon because it's part of our regular respiration

Elodia [21]2 years ago
5 0

Answer:

D

Explanation:

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knowing that the reaction of potassium in water is extremely exothermic, what would be the problem with adding a large piece of
anygoal [31]

Answer:

Explanation:

If the reaction is really exothermic (and it is) then the water would spatter all over the place. It would boil off if the container could hold it. It would also react according to the following reaction.

You are talking about a reaction like

2K + 2HOH = 2KOH + H2

8 0
3 years ago
Which of the following months would be the darkest at the South Pole?
son4ous [18]

Answer:

December.

Explanation:

6 0
3 years ago
Submit At 25.0 C, a 10.00 L vessel is filled with 5.00 atm of Gas A and 7.89 atm of Gas B. What is the mole fraction of Gas B?
Firlakuza [10]

Answer:

the mole fraction of Gas B is xB= 0.612 (61.2%)

Explanation:

Assuming ideal gas behaviour of A and B, then

pA*V=nA*R*T

pB*V=nB*R*T

where

V= volume = 10 L

T= temperature= 25°C= 298 K

pA and pB= partial pressures of A and B respectively = 5 atm and 7.89 atm

R= ideal gas constant = 0.082 atm*L/(mol*K)

therefore

nA= (pA*V)/(R*T) = 5 atm* 10 L /(0.082 atm*L/(mol*K) * 298 K) = 2.04 mole

nB= (pB*V)/(R*T) = 7.89 atm* 10 L /(0.082 atm*L/(mol*K) * 298 K) = 3.22 mole

therefore the total number of moles is

n = nA +nB= 2.04 mole +  3.22 mole = 5.26 mole

the mole fraction of Gas B is then

xB= nB/n= 3.22 mole/5.26 mole = 0.612

xB= 0.612

Note

another way to obtain it is through Dalton's law

P=pB*xB , P = pA+pB → xB = pB/(pA+pB) = 7.69 atm/( 5 atm + 7.89 atm) = 0.612

5 0
3 years ago
How many milliliters of water are needed to prepare a 3.5M solution of NaOH if you have .5mol of the solute
Mamont248 [21]

Answer:

1335.12 mL of H2O

Explanation:

To calculate the mililiters of water that the solution needs, it is necessary to know that the volume of the solution is equal to the volume of the solute (NaOH) plus the volume of the solvent (H2O).

From the molarity formula we can first calculate the volume of the solution:

M=\frac{solute moles}{solution volume}

Solutionvolume=\frac{solute moles}{M} =\frac{5mol}{3.5\frac{mol}{L} } =1.429L

The volume of the solution as we said previously is:

Solution volume = solute volume + solvent volume

To determine the volume of the solute we first obtain the grams of NaOH through the molecular weight formula:

MW=\frac{mass}{mol}

Mass=MW*mol=39.997\frac{g}{mol} *5mol=199.985g

Now with the density of NaOH the milliliters of solute can be determined:

d=\frac{mass}{volume}

Volume=\frac{mass}{d} =\frac{199.985g}{2.13\frac{g}{mL} } =93.88mL of NaOH

Having the volume of the solution and the volume of the solute, the volume of the solvent H2O can be calculated:

Solvent volume = solution volume - solute volume

Solvent volume = 1429 mL -  93.88 mL = 1335.12 mL of H2O

7 0
3 years ago
1. If 22.5 L of nitrogen at 734 mm Hg are compressed to 702 mm Hg at constant
Alika [10]

Answer:

The answer to your question is   V2 = 23.52 l

Explanation:

Data

Volume 1 = V1 = 22.5 l

Pressure 1 = P1 = 734 mmHg

Volume 2 = V2 = ?

Pressure 2 = 702 mmHg

Process

To solve this problem use Boyle's law.

                      P1V1 = P2V2

-Solve for V2

                          V2 = P1V1 / P2

-Substitution

                          V2 = (734 x 22.5) / 702

-Simplification

                           V2 = 16515 / 702

-Result

                           V2 = 23.52 l

-Conclusion

If we diminish the pressure, the volume will be higher.

8 0
3 years ago
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