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3 years ago

8

ASAP ILL GIVE BRAINLIEST ! IF YOU CAN ANSWER AT LEAST ONE TY

1 answer:

lesantik [10]3 years ago

3 0

Answer:

Project shadow #KARMA be there

Explanation:

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4Cr(s)+3O2 (g )= Cr2O3 (s)<br> Find the theoretical yield in moles and grams

Assoli18 [71]

The balanced reaction is:

<span>4Cr(s)+3O2 (g )= Cr2O3 (s)

Since we are not given the amount of any of the reactants, we assume we have one gram of chromium. Calculations are as follows:

1 g Cr ( 1 mol Cr / 52 g Cr ) ( 1 mol Cr2O3 / 4 mol Cr ) = <span>0.005 mol Cr2O3

</span></span>0.005 mol Cr2O3 (151.99 g Cr2O3 / 1 mol Cr2O3 ) = 0.7307 g <span>Cr2O3
</span>
Therefore, the theoretical yield for 1 gram of Cr is 0.005 mol Cr2O3 or 0.7307 g Cr2O3.

7 0

3 years ago

The half-life of a radioactive isotope is the amount of time it takes for a quantity of radioactive material to decay to one-hal

finlep [7]

Answer: The statement is true

Explanation:

The half-life of a radioactive isotope is the time taken for half of the total number of atoms in a given sample of the isotope to decay.

For instance

The half-life of radium is 1622 years. This means that if we have 1000 radium atoms at the beginning, then at the end of 1622 years, 500 atoms would have disintegrated, leaving 500 undecayed radium atoms

Thus, the statement is true

3 0

3 years ago

What volume of barium chloride, BaCl2 is needed to make a 2.5 M barium

Zolol [24]

Answer:

0.18 L

Explanation:

You can find the volume using the molarity ratio:

Molarity = moles / volume (L)

You can plug the given values into the equation and simplify to find the volume.

Molarity = moles / volume <----- Molarity ratio

2.5 M = 0.45 moles / volume <----- Insert values

(2.5 M) x volume = 0.45 moles <----- Multiply both sides by volume

volume = 0.18 L <----- Divide both sides by 2.5

4 0

2 years ago

. The Henry's law constant for helium gas in water at 30 ∘C is 3.7×10−4M/atm; the constant for N2 at 30 ∘C is 6.0×10−4M/atm. a.

ludmilkaskok [199]

Explanation:

1) Henry's law states that the amount of gas dissolved or molar solubility of gas is directly proportional to the partial pressure of the liquid.

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$M_{g}=K_H\times p_{g}$

where,

$K_H$ = Henry's constant

$p_{He}$ = partial pressure of gas

a) $K_H=3.7\times 10^{-4} M/atm$

$p_{He}=2.1 atm$

Putting values in above equation, we get:

$M_{He}=3.7\times 10^{-4} M/atm\times 2.1 atm = 7.77\times 10^{-4} M$

The solubility of helium gas is $7.77\times 10^{-4} M$

b) $K_H=6.0\times 10^{-4} M/atm$

$p_{N_2}=2.1 atm$

Putting values in above equation, we get:

$M_{He}=6.0\times 10^{-4} M/atm\times 2.1 atm = 1.26\times 10^{-3} M$

The solubility of nitrogen gas is $1.26\times 10^{-3} M$

2)

a) Mass of solute or methanol , m= 14.7 g

Mass of solvent or water , m'= 186 g

Mass of the solution = M = m + m' = 14.7 g + 186 g = 200.7 g

$w/w\%=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 100$

$=\frac{14.7 g}{200.7 g}\times 100=7.32\%$

The mass percent of methanol is 7.32%.

b) Molality is defined as moles of solute per kilograms of solvent.

$m=\frac{\text{Moles of solute}}{\text{Mass of solvent in kg}}$

Moles of methanol = $\frac{14.7 g}{32 g/mol}=0.4594 mol$

Mass of solvent = 186 g = 0.186 kg

$m=\frac{0.4594 mol}{0.186 kg}=2.4610 mol/kg$

The molality of methanol is 2.4610 mol/kg.

4 0

3 years ago

Help me please.<br>List two properties of a material that you can observe using your senses

sasho [114]

Well I would guess the 5 common senses if thats what it is called like seeing hearing and stuff like that

5 0

4 years ago