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2 years ago

Which of the following statements about semi-empirical methods are true?

Chemistry

1 answer:

juin [17]2 years ago

5 0

Answer:

Explanation:

The correct statement about semi-empirical methods is

It combines a theoretically sound model of bonding with some experimentally determined parameters.

These methods are typically referred to by acronyms which encode some of the underlying theoretical assumptions.

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Which condition must exist in order for conduction to occur between two substances?

Sveta_85 [38]

Answer: B

Explanation:

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2 years ago

Read 2 more answers

In order for rock formations to move the plates__________ .

ANEK [815]

Igneous rocks are found where plates diverge, as lava rises and fills the gap between the plates. Igneous rocks also form where plates converge. The subducting plate melts as it sinks into the crust of the Earth, and the melt rises into the overriding plate forming volcanoes.

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3 years ago

A 0.15 m solution of chloroacetic acid has a ph of 1.86. What is the value of ka for this acid?

dem82 [27]

Answer: $1.67\times 10^{-3}$

Explanation:

$ClCH_2COOH\rightarrow ClCH_2COO^-+H^+$

cM 0 0

$c-c\alpha$ $c\alpha$ $c\alpha$

So dissociation constant will be:

$K_a=\frac{(c\alpha)^{2}}{c-c\alpha}$

Given: c = 0.15 M

pH = 1.86

$K_a$ = ?

Putting in the values we get:

Also $pH=-log[H^+]$

$1.86=-log[H^+]$

$[H^+]=0.01$

$[H^+]=c\times \alpha$

$0.01=0.15\times \alpha$

$\alpha=0.06$

As $[H^+]=[ClCH_2COO^-]=0.01$

$K_a=\frac{(0.01)^2}{(0.15-0.15\times 0.06)}$

$K_a=1.67\times 10^{-3]$

Thus the vale of $K_a$ for the acid is $1.67\times 10^{-3}$

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3 years ago

The photograph below shows the East African Rift Valley in Africa. Which tectonic movement

GalinKa [24]

Answer:

divergence of continental crust

Explanation:

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3 years ago

If the volume occupied by 0.500 mol of nitrogen gas at 0°C is 11.2 L, then the volume occupied by 2.00 mol of nitrogen gas at th

Paraphin [41]

Avagadros law states that volume of gas is directly proportional to number of moles of gas at constant pressure and temperature.
$\frac{V1}{n1} = \frac{V2}{n2}$
where V -volume , n - number of moles
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
substituting these values in the equation
$\frac{11.2 L}{0.500 mol} = \frac{V}{2.00 mol}$
V = 44.8 L
answer is C. 44.8 L

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3 years ago