What is the symbol for the ion that contains 12 protons, 10 electrons, and 12 neutrons?

What mass of sodium chloride is needed to prepare 200 ml of a 0.1 M solution

Nikolay [14]

Answer:

C. 1.17 grams

Explanation:

The molarity is the no. of moles of solute in a 1.0 L of the solution.

M = (mass/molar mass)solute x (1000/ V)

M = 0.1 M, mass = ??? g, molar mass of NaCl = 58.44 g/mol, V = 200.0 mL.

∴ mass of NaCl = (M)(molar mass)(V)/1000 = (0.1 M)(58.44 g/mol)(200.0 mL)/1000 = 1.168 g ≅ 1.17 g.

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3 years ago

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How many molecules of carbon dioxide are dissolved in 0.550 L of water at 25 °C if the pressure of CO2 above the water is 0.250

Grace [21]

Answer: The number of molecules of carbon dioxide gas are $2.815\times 10^{21}$

Explanation:

To calculate the molar solubility, we use the equation given by Henry's law, which is:

$C_{CO_2}=K_H\times p_{CO_2}$

where,

$K_H$ = Henry's constant = $0.034mol/L.atm$

$C_{CO_2}$ = molar solubility of carbon dioxide gas

$p_{CO_2}$ = pressure of carbon dioxide gas = 0.250 atm

Putting values in above equation, we get:

$C_{CO_2}=0.034mol/L.atm\times 0.250atm\\\\C_{CO_2}=8.5\times 10^{-3}M$

To calculate the number of moles for given molarity, we use the equation:

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

Molarity of carbon dioxide = $8.5\times 10^{-5}M$

Volume of solution = 0.550 L

Putting values in above equation, we get:

$8.5\times 10^{-3}M=\frac{\text{Moles of }CO_2}{0.550L}\\\\\text{Moles of }CO_2=(8.5\times 10^{-3}mol/L\times 0.550L)=4.675\times 10^{-3}mol$

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of molecules

So, $4.675\times 10^{-3}$ moles of carbon dioxide will contain = $(6.022\times 10^{23}\times 4.675\times 10^{-3})=2.815\times 10^{21}$ number of molecules

Hence, the number of molecules of carbon dioxide gas are $2.815\times 10^{21}$

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What does the group number on the periodic table tell you about the electron configuration of a

jarptica [38.1K]

Answer:

The group number in the periodic table represents number of valence electrons of the elements in a certain group.

Explanation:

There are s, p, d, and f blocks, which you can see in periodic table

The s-block and p-block together are usually considered main-group elements, the d-block corresponds to the transition metals, and the f-block encompasses nearly all of the lanthanides (like lanthanum) and the actinides (like actinium)

There are three main principles, which may useful for you:

The Pauli exclusion rule basically says that at most, 2 electrons are allowed to be in the same orbital.
Hund’s rule explains that each orbital in the subshell must be occupied with one single electron first before two electrons can be in the same orbital.
The Aufbau process describes the process of adding electron configuration to each individualized element in the periodic table.

Hope this helps!

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3 years ago

In which 2 states of matter can a substance take the shape of its container?

Natasha2012 [34]

Answer:

solid and liquid

Explanation:

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People who work with radioactive materials often wear a _________ to reveal how much radiation they have been exposed to. A. fil

nekit [7.7K]

People who work with radioactive materials often wear a film badge to reveal how much radiation they have been exposed to. The film badge dosimeter or the film badge is a dosimeter worn by these people working with materials that are radioactive for the purpose of monitoring cumulative radiation dose due to ionizing radiation. The badge has two parts; the photographic film, and a holder.

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3 years ago

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