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2 years ago

How much of a 15.0M stock solution do you need to prepare 250ml of a 2.35ml hf solution?

1 answer:

3 0

Using the relationship M1V1 = M2V2 where M1 and M2 are the molar concentrations (mol/L or mmol/ml) and V1 and V2 are the volumes of the solutions, we can arrive at the following answer for the given problem:

15.0M (L of stock solution) = 2.35M (0.25L) *all volumes were converted to liters.

L of stock solution = (2.35*0.25)/15.0

Therefore, 0.0392L or 39.17 ml of stock solution is needed.

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The molar mass of an unknown gas was measured by an effusion experiment. It was found that it took 60 s for the gas to effuse, w

Marizza181 [45]

Answer:

The molar mass of the gas is 44 g/mol

Explanation:

It is possible to solve this problem using Graham's law that says: Rates of effusion are inversely dependent on the square of the mass of each gas. That is:

$\frac{r_1}{r_2} =\frac{\sqrt{M_2} }{\sqrt{M_1} }$

If rate of effusion of nitrogen is Xdistance / 48s and for the unknown gas is X distance / 60s and mass of nitrogen gas is 28g/mol (N₂):

$\frac{X/48s}{X/60s} =\frac{\sqrt{M_2} }{\sqrt{28g/mol} }$

6,61 = √M₂

44g/mol = M₂

The molar mass of the gas is 44 g/mol

I hope it helps!

4 0

3 years ago

What place is a landscape featured that forms when plate movement forces the crust to bend downward

Olenka [21]

The answer is syncline

7 0

2 years ago

a certain compound was found to contain 54.0 g of carbon and 10.5 grams of hydrogen. its relative molecular mass is 86.0. find t

dexar [7]

Answer:

empirical formula = C3H7

molecular formula = C6H14

3 0

3 years ago

Define shielding and effective nuclear charge. What is the connection between the two?

ivolga24 [154]

Answer:

The relation between the shielding and effective nuclear charge is given as

$Z_{eff} = Z -S$

where s denote shielding

z_{eff} denote effective nuclear charge

Z - atomic number

Explanation:

shielding is referred to as the repulsion of an outermost electron to the pull of electron from valence shell. Higher the electron in valence shell higher will be the shielding effects.

Effective nuclear charge is the amount of net positive charge that valence electron has.

The relation between the shielding and the effective nuclear charge is given as

$Z_{eff} = Z -S$

wheres denote shielding

z_{eff} denote effective nuclear charge

Z - atomic number

8 0

3 years ago

Give the quantum number set for one electron in the 3p sub level of a sulfur (S)

vesna_86 [32]

Answer:- Atomic number for sulfur is 16 and it's electron configuration is $1s^2 2s^2 2p^6 3s^2 3p^4$ . Here, there are total for electrons in 3p and the set of quantum numbers for these 4 electrons would be as..

For the first electron of 3p-

n = 3, l = 1, ml = -1 and ms = +(1/2)

for the second electron of 3p-

n = 3, l = 1, ml = 0 and ms = +(1/2)

for the third electron of 3p-

n = 3, l = 1, ml = +1 and ms = +(1/2)

and for the fourth electron of 3p-

n = 3, l = 1, ml = -1 and ms = -(1/2)

3 0

3 years ago