Please help urgently with question 3!!!

Serga [27]

It is very important to know the shape of a molecule if one is to understand its reactions. It is also desirable to have a simple method to predict the geometries of compounds. For main group compounds, the VSEPR method is such a predictive tool and unsurpassed as a handy predictive method.

7 0

3 years ago

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Which gas below has the largest number of moles at STP?

ArbitrLikvidat [17]

Answer:

a.) 22.4 L Ne.

Explanation:

It is known that every 1.0 mol of any gas occupies 22.4 L.

For the options:

22.4 L Ne:

It represents 1.0 mol of Ne.

20 L Ar:

using cross multiplication:

1.0 mol occupies → 22.4 L.

??? mol occupies → 20 L.

The no. of moles of (20 L) Ar = (1.0 mol)(20 L)/(22.4 L) = 0.8929 mol.

2.24 L Xe:

using cross multiplication:

1.0 mol occupies → 22.4 L.

??? mol occupies → 2.24 L.

The no. of moles of (2.24 L) Xe = (1.0 mol)(2.24 L)/(22.4 L) = 0.1 mol.

So, the gas that has the largest number of moles at STP is: a.) 22.4 L Ne.

6 0

3 years ago

What effect would the incomplete drying of a sample (for example, the incomplete removal of a re-crystallization solvent) on per

Varvara68 [4.7K]

Answer:

It will lead to overestimation of the percent recovery

Explanation:

The percent recovery refers to the percentage of the pure compound recovered after a chemical process. It is a ratio of the pure compound recovered to the original substance multiplied by 100%.

If the sample was incompletely dried and the recrystallization solvent is still present, the percent recovery will be overestimated and we will have a value that is greater than the accurate percent recovery due to solvent impurities present.

5 0

2 years ago

Suppose you need to heat food. What wave type from the electromagnetic spectrum could you use?

N76 [4]

Answer:

Microwave radiation

Explanation:

This radiation is the one used in microwaves.

8 0

2 years ago

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RATE LAW QUESTION !

vivado [14]

In general, we have this rate law express.:

$\mathrm{Rate} = k \cdot [A]^x [B]^y$
we need to find x and y

ignore the given overall chemical reaction equation as we only preduct rate law from mechanism (not given to us).

then we go to compare two experiments in which only one concentration is changed

compare experiments 1 and 4 to find the effect of changing [B]
divide the larger [B] (experiment 4) by the smaller [B] (experiment 1) and call it Δ[B]

Δ[B]= 0.3 / 0.1 = 3

now divide experiment 4 by experient 1 for the given reaction rates, calling it ΔRate:

ΔRate = 1.7 × 10⁻⁵ / 5.5 × 10⁻⁶ = 34/11 = 3.090909...

solve for y in the equation $\Delta \mathrm{Rate} = \Delta [B]^y$

$3.09 = (3)^y \implies y \approx 1$

To this point, $\mathrm{Rate} = k \cdot [A]^x [B]^1$

do the same to find x.
choose two experiments in which only the concentration of B is unchanged:

Dividing experiment 3 by experiment 2:
Δ[A] = 0.4 / 0.2 = 2
ΔRate = 8.8 × 10⁻⁵ / 2.2 × 10⁻⁵ = 4

solve for x for $\Delta \mathrm{Rate} = \Delta [A]^x$

$4= (2)^x \implies x = 2$

the rate law is

Rate = k·[A]²[B]

6 0

2 years ago