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2 years ago

3. How are the protons held in the

Chemistry

1 answer:

sergiy2304 [10]2 years ago

8 0

They are help together by the strong nuclear force from neutrons

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A plastic 2L soda bottle is flexible enough that the volume of the bottle can change even without opening it. If you have an emp

Aneli [31]

Answer: The new volume be if you put it in your freezer is 1.8 L

Explanation:

To calculate the final temperature of the system, we use the equation given by Charles' Law. This law states that volume of the gas is directly proportional to the temperature of the gas at constant pressure.

Mathematically,

$\frac{V_1}{T_1}=\frac{V_2}{T_2}$

where,

$V_1\text{ and }T_1$ are the initial volume and temperature of the gas.

$V_2\text{ and }T_2$ are the final volume and temperature of the gas.

We are given:

$V_1=2L\\T_1=25^oC=(25+273)K=298K\\V_2=?\\T_2=-4.0^oC=((-4)+273)K=269K$

Putting values in above equation, we get:

$\frac{2}{298}=\frac{V_2}{269}\\\\V_2=1.8L$

The new volume be if you put it in your freezer is 1.8 L

8 0

3 years ago

Which one of the following statements BEST describes a chemical reaction?

Natalija [7]

Answer: The correct statement is (A new substance is formed and the process can usually NOT be undone.)

Explanation:

A chemical reaction is simply defined as the reaction between two or more elements in which a new substance is formed and the process can usually not be undone. Different types of chemical reaction includes:

-- combination reaction: this occurs when two or more reactants form a product. For example: In the burning of coal, It combines with oxygen to produce carbon dioxide. Also in the burning of wood, carbon dioxide is given off and ashes are formed. Because new substance is being formed, they often can't be undone. The ashes formed can't be changed back into wood. Other types of chemical reaction are listed below.

-- Decomposition reaction

-- Single displacement reaction

-- Double displacement reaction

-- combustion reaction

-- Redox reaction

For the product of a chemical reaction to be undone (reversed), it has to undergo another chemical process different from the one that produced it.

8 0

2 years ago

Which of the following describes the arrangement of valence electrons in a bond between H and F?

Sloan [31]

C; The Valence electrons spend more time around the atom of F

6 0

2 years ago

A compound is 42.9% C, 2.4% H, 16.7% N, and 38.1% O, by mass. Addition of 6.45 g of this compound to 50.0 mL benzene, lowers the

Romashka [77]

This is an incomplete question, here is a complete question.

A compound is 42.9% C, 2.4% H, 16.7% N and 38.1% O by mass. Addition of 6.45 g of this compound to 50.0 mL benzene, C₆H₆ (d= 0.879 g/mL; Kf= 5.12 degrees Celsius/m), lowers the freezing point from 5.53 to 1.37 degrees Celsius. What is the molecular formula of this compound?

Answer : The molecular of the compound is, $C_6H_4N_2O_4$

Explanation :

First we have to calculate the mass of benzene.

$\text{Mass of benzene}=\text{Density of benzene}\times \text{Volume of benzene}$

$\text{Mass of benzene}=0.879g/mL\times 50.0mL=43.95g$

Now we have to calculate the molar mass of unknown compound.

Given:

Mass of unknown compound (solute) = 6.45 g

Mass of benzene (solvent) = 43.95 g = 0.04395 kg

Formula used :

$\Delta T_f=K_f\times m\\\\\Delta T_f=K_f\times\frac{\text{Mass of unknown compound}}{\text{Molar mass of unknown compound}\times \text{Mass of benzene in Kg}}$

where,

$\Delta T_f$ = change in freezing point = $5.53-1.37=4.16^oC$

$\Delta T_s$ = freezing point of solution

$\Delta T^o$ = freezing point of benzene

Molal-freezing-point-depression constant $(K_f)$ for benzene = $5.12^oC/m$

m = molality

Now put all the given values in this formula, we get

$4.16^oC=(5.12^oC/m)\times \frac{6.45g}{\text{Molar mass of unknown compound}\times 0.04395kg}$

$\text{Molar mass of unknown compound}=180.6g/mol$

If percentage are given then we are taking total mass is 100 grams.

So, the mass of each element is equal to the percentage given.

Mass of C = 42.9 g

Mass of H = 2.4 g

Mass of N = 16.7 g

Mass of O = 38.1 g

Molar mass of C = 12 g/mole

Molar mass of H = 1 g/mole

Molar mass of N = 14 g/mole

Molar mass of O = 16 g/mole

Step 1 : convert given masses into moles.

Moles of C = $\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{42.9g}{12g/mole}=3.575moles$

Moles of H = $\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{2.4g}{1g/mole}=2.4moles$

Moles of N = $\frac{\text{ given mass of N}}{\text{ molar mass of N}}= \frac{16.7g}{14g/mole}=1.193moles$

Moles of O = $\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{38.1g}{16g/mole}=2.381moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{3.575}{1.193}=2.99\approx 3$

For H = $\frac{2.4}{1.193}=2.01\approx 2$

For N = $\frac{1.193}{1.193}=1$

For O = $\frac{2.381}{1.193}=1.99\approx 2$

The ratio of C : H : N : O = 3 : 2 : 1 : 2

The mole ratio of the element is represented by subscripts in empirical formula.

The Empirical formula = $C_3H_2N_1O_2$

The empirical formula weight = 3(12) + 2(1) + 1(14) + 2(16) = 84 gram/eq

Now we have to calculate the molecular formula of the compound.

Formula used :

$n=\frac{\text{Molecular formula}}{\text{Empirical formula weight}}$

$n=\frac{180.6}{84}=2$

Molecular formula = $(C_3H_2N_1O_2)_n=(C_3H_2N_1O_2)_2=C_6H_4N_2O_4$

Therefore, the molecular of the compound is, $C_6H_4N_2O_4$

3 0

3 years ago

Do atoms lend and borrow electrons from inner shells

zaharov [31]

False. They don't borrow electrons at all. They already have their respective electron affinities. This is called as electronegativity, and it's an occurence where it already has its own from its actual structure. It never borrows any electrons at all.

4 0

3 years ago