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3 years ago

11

A student finds that an unknown element reacts with elements from Group 2 (IIA). To which group does the unknown element most li

kely belong?
A.
Group 1 (IA)

B.
Group 3 (IIIB)

C.
Group 16 (VIA)

D.
Group 18 (VIIIA)

2 answers:

REY [17]3 years ago

8 0

Answer:

Explanation:

A because a

Sedaia [141]3 years ago

4 0

A just because though heh

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at room temperature table salt is a solid and mercury is a liquid. what conclusion can you draw about the melting points of thes

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Table slat has a low melting pointy while mercury has a high one
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Which gas would have the slowest rate of diffusion, assuming that all gases are at the same temperature?

Iteru [2.4K]

Answer: radon (atomic mass 222 amu

Explanation:

To calculate the rate of diffusion of gas, we use Graham's Law.

This law states that the rate of effusion or diffusion of gas is inversely proportional to the square root of the molar mass of the gas. The equation given by this law follows:

$\text{Rate of diffusion}\propto \frac{1}{\sqrt{\text{Molar mass of the gas}}}$

atomic mass of krypton= 83.8 amu

atomic mass of argon= 39.95 amu

atomic mass of xenon = 131.3 amu

atomic mass of radon= 222 amu

Thus as atomic mass of radon is highest, its rate of diffusion is slowest.

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3 years ago

Metals are considered to be ___________________ because they let electricity flow.

Yuri [45]

Answer:

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Explanation:

Because they consist of lattice of atoms with free electrons and these free electrons allows current to flow through.

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3 years ago

Three reasons for air is mixture and water is compound

zhannawk [14.2K]

1. air components change from place to place, while water will just stay the same

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Don't take my word for it, this is just what I learned back in middle school.

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Read 2 more answers

Tris is a molecule that can be used to prepare buffers for biochemical experiments. It exists in two forms: Tris (a base) and Tr

ale4655 [162]

Solution :

For the reaction :

$\text{TrisH}^+ + H_2O \rightarrow \text{Trish}^- + H_3O^+$

we have

$Ka = \frac{[\text{Tris}^- \times H_3O]}{\text{Tris}^+}$

$=\frac{x^2}{0.02 -x}$

$=8.32 \times 10^{-9}$

Clearing $x$ , we have $x = 1.29 \times 10^{-5} \text{ moles of acid}$

So to reach $\text{pH} = 7.8 (\text{pOH}= 14-7.8=6.2)$ , one must have the $\text{OH}^-$ concentration of the :

$\text{[OH}^-]=10^{-pOH} = 6.31 \times 10^{-7} \text{ moles of base}$

So we can add enough of 1 M NaOH in order to neutralize the acid that is calculated above and also adding the calculated base.

$\text {n NaOH}=1.29 \times 10^{-5}+6.31 \times 10^{-7}$

$= 1.35 \times 10^{-5} \text{ moles}$

Volume NaOH $= 1.35 \times 10^{-5} \text{ moles} \times \frac{1000 \text{ mL}}{1 \text{ mol}} = 0.0135 \text{ mL}$

Tris mass $H^+ = 0.02 \text{ mol} \times 157.6 \text{ g/mol}=3.152 \text{ g}$

Now to prepare the said solution we must mix:

$3.152 \text{ g Tris H} + 0.0135 \text{ mL NaOH} \ 1 M$ gauge to 1000 mL with water.

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3 years ago