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Alenkinab [10]
3 years ago
7

A chemist weighed out 20.7 g of sodium . Calculate the number of moles of sodium she weighed out

Chemistry
1 answer:
Pachacha [2.7K]3 years ago
8 0

Answer:

about 0.9 mol

Explanation:

there are 22.990 g/mol of Na

20.7/22.99 = 0.900391 mol

about 0.9 mol

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The following are formed as white precipitates in solution except
aniked [119]

Answer:

A. Iron (III) hydroxide

Explanation:

Orange-brown or rust

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3 years ago
Read 2 more answers
How much time would it take to distribute one avagadro's number of wheat grains if 10^10 grains are A)1.9*10^2 years B)1.9*10^10
Makovka662 [10]

Answer:

It takes  1.9 \times 10^{6} years to distribute all the grains.

Explanation:

In one second, 10^{10} grains of wheat are distributed.

We are supposed to find the time it would take to Distribute Avogadro number of grains.

1 avogadro number = 6.022 \times 10^{23}

Number of grains distributed in 1 day = 86400 \times 10^{10}

                                                             = 8.64 \times 10^{14}

Number of grains distributed in 1 year= 8.64 \times 10^{14} \times 365

                                 = 3.1536 \times 10^{17}

Time taken = \frac{Number of grains to be distributed}{grains distributed in 1 year}

            = \frac {6.022 \times 10^{23}}{3.1536\times 10^{17}}

            = 1.9 \times 10^{6}

7 0
3 years ago
Pre-lab questions 1. a concentration gradient affects the direction that solutes diffuse. describe how molecules move with respe
VLD [36.1K]

Just like how heat moves from a region of higher temperature to a region of lower temperature, molecules also tend to move from a region of higher concentration to a region of lower concentration. This is called natural diffusion and is naturally happening to reach stability.

7 0
4 years ago
Which of the following groups of elements have no electronegativity?
natulia [17]

Answer: Noble gases

Explanation:

Electronegativity is the ability of an atom to gain an electron. Noble gases already have 8 electrons, so they don’t need to gain electrons. If they don’t gain electrons, it has no electronegativity.

6 0
3 years ago
At what pressure does the mean free path of argon at 20 degrees celsius become comparable to the diameter of a 100 cm3​vessel th
inn [45]

Answer:

The mean free path of argon molecules becomes comparable to the diameter of this container at a pressure of 0.195 Pa

Explanation:

<u>Step 1</u>: Calculate the volume of a spherical container V

V = (4π*r³)/3

r = (3V/4π)^1/3

2r = d = 2*(3V/4π)^1/3

with r= radius

with d= diameter

The diameter is:

d= 2*(3V/4π)^1/3

d= 2*(3*100cm³/4π)^1/3

d= 5.76 cm

<u>Step2 </u>: Define the free path lambda  λ of argon

with  λ =k*T/ σp

with p = kT/σλ

with T= temperature = 20°C = 293.15 Kelvin

with k = Boltzmann's constant = 1.381 * 10^-23 J/K

with p = the atmospheric pressure

with σ = 0.36 nm²

p = kT/σλ

p = (1.38 * 10^-23 J*K^-1 * 1Pa *m³/1J)*(293,15K) /(0.36 nm²*(10^-9/ 1nm)² *(5.76cm* 10^-2m/1cm)

p = 0.195 Pa

The mean free path of argon molecules becomes comparable to the diameter of this container at a pressure of 0.195 Pa

5 0
3 years ago
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