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3 years ago

Look up sodium in the Periodic Table (Na). Then, answer the following questions

1 answer:

4 0

There are 11 electrons in Sodium(Na)
The first shell can hold 2 electrons
The second shell can hold 8 electrons
The third shell can also hold 8 electrons but there is only 1 left

so the answer is 2, 8, 1

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inysia [295]

Answer:

Explanation:

Solar panels are not toxic, so option A goes out the window.

Aesthetics don't really matter, so option B follows it out.

Option C makes a little sense, but less so than Option D. They aren't nearly as heavy as some of our current energy production methods.

Solar panels are expensive, hard to store properly, and most are between 15 and 20 percent efficiency, compared with a diesel motor's 40 percent.

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3 years ago

Which three temperature readings all mean the same thing?

allochka39001 [22]

Answer: The correct answer is D. 273 Kelvin, 0 degrees Celsius, 32 degrees Fahrenheit.

Explanation:

Conversion of degree Celsius to Kelvin :

K=^oC+273

Conversion of degree Celsius to degrees Fahrenheit :

^oF=(\frac{9}{5}\times ^oC)+32

By using these two conversion factors, we get the three temperature readings all mean the same thing.

For option A :

K=^oC+273=100+273=373K

^oF=(\frac{9}{5}\times ^oC)+32=(\frac{9}{5}\times 100)+32=212^oF

For option B :

K=^oC+273=100+273=373K

^oF=(\frac{9}{5}\times ^oC)+32=(\frac{9}{5}\times 100)+32=212^oF

For option C :

K=^oC+273=0+273=273K

^oF=(\frac{9}{5}\times ^oC)+32=(\frac{9}{5}\times 0)+32=32^oF

For option D :

K=^oC+273=0+273=273K

^oF=(\frac{9}{5}\times ^oC)+32=(\frac{9}{5}\times 0)+32=32^oF

From the given options, only option (D) is correct.

Hence, the correct option is, (D) 273 Kelvin, 0 degrees Celsius, 32 degrees Fahrenheit

Hope this helps!

8 0

3 years ago

Read 2 more answers

What type of combustion will happen in a bunsen burner when the flame is yellow

andrew11 [14]

Answer:

combustion of methane gass will take place when the flame is yellow

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3 years ago

An unknown salt is either NaF, NaCl, or NaOCl. When 0.050 mol of the salt is dissolved in water to form 0.500 L of solution, the

victus00 [196]

Answer: The unknown salt is NaF

Explanation:

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Moles of salt = 0.050 moles

Volume of solution = 0.500 L

Putting values in above equation, we get:

$\text{Molarity of salt}=\frac{0.050mol}{0.500L}\\\\\text{Molarity of salt}=0.1M$

To calculate the hydroxide ion concentration, we first calculate pOH of the solution, which is:

pH + pOH = 14

We are given:

pH = 8.08

$pOH=14-8.08=5.92$

To calculate pOH of the solution, we use the equation:

$pOH=-\log[OH^-]$

Putting values in above equation, we get:

$5.92=-\log[OH^-]$

$[OH^-]=10^{-5.92}=1.202\times 10^{-6}M$

The unknown salt given are formed by the combination of weak acid and strong acid which is NaOH

The chemical equation for the hydrolysis of $X^-$ ions follows:

$X^-(aq.)+H_2O(l)\rightleftharpoons HX(aq.)+OH^-(aq.);K_b$

Initial: 0.1

At eqllm: 0.1-x x x

Concentration of $OH^-=x=1.202\times 10^{-6}M$

The expression of $K_b$ for above equation follows:

$K_b=\frac{[OH^-][HX]}{[X^-]}$

Putting values in above expression, we get:

$K_b=\frac{(1.202\times 10^{-6})\times (1.202\times 10^{-6})}{(1-(1.202\times 10^{-6}))}\\\\K_b=1.445\times 10^{-11}M$

To calculate the acid dissociation constant for the given base dissociation constant, we use the equation:

$K_w=K_b\times K_a$

where,

$K_w$ = Ionic product of water = $10^{-14}$

$K_a$ = Acid dissociation constant

$K_b$ = Base dissociation constant = $1.445\times 10^{-11}$

Putting values in above equation, we get:

$10^{-14}=1.445\times 10^{-11}\times K_a\\\\K_a=\frac{10^{-14}}{1.445\times 10^{-11}}=6.92\times 10^{-4}$

We know that:

$K_a\text{ for HF}=6.8\times 10^{-6}$

$K_a\text{ for HCl}=1.3\times 10^{6}$

$K_a\text{ for HClO}=3.0\times 10^{-8}$

So, the calculated $K_a$ is approximately equal to the $K_a$ of HF

Hence, the unknown salt is NaF

6 0

3 years ago

“What is the group number for the elements that have a stable number of electrons in their outer energy level?”

Studentka2010 [4]

Answer:

A. 18

Explanation:

Sulfur number sixteen forms a negative

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3 0

3 years ago