Oxygen gains two electrons when it bonds to form a complete outer shell and magnesium loses two electrons when bonding to gain its full outer shell.

As electrons are negative, the oxygen (which gains electrons) will become negative and the magnesium (which loses electrons) will become positive.

The negative and positive ions will then attract to one another due to the magnetic pull of the positive and negative.

8 0

3 years ago

Calculate the concentration expressed in percent, if 10 g of NaOH is diluted to 500 ml with water.

Zepler [3.9K]

If 10 g of NaOH is diluted to 500 ml with water then the concentration expressed in percent is 0.5 mol/L .

Calculation ,

Given mass in gram = 10 g

Number of moles = given mass /molar mass = 10 g / 40 g/mol = 0.25mole

Given volume in ml = 500 ml

Given volume in liter = 0.5 L

Putting the value of mass and volume in equation i we get concentration expressed in percent .

C = number of moles ×100/ volume in liter = 0.25mole ×100/ 0.5 L

C = 0.5 mol/L

Concentration of solution in terms of percentage can be expressed in two ways

1) percentage by mass

2) percentage by volume

Hence, for liquid solutions, concentration is expressed in terms of percentage by volume.

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5 0

1 year ago

What volume (in liters) of a solution contains 0.14 mol of KCl?

oksano4ka [1.4K]

Answer:

$\boxed {\boxed {\sf 0.078 \ L }}$

Explanation:

We are asked to find the volume of a solution given the moles of solute and molarity.

Molarity is a measure of concentration in moles per liter. It is calculated using the following formula:

$molarity= \frac{moles \ of \ solute}{liters \ of \ solution}$

We know there are 0.14 moles of potassium chloride (KCl), which is the solute. The molarity of the solution is 1.8 molar or 1.8 moles of potassium chloride per liter.

moles of solute = 0.14 mol KCl
molarity= 1.8 mol KCl/ L
liters of solution=x

Substitute these values/variables into the formula.

$1.8 \ mol \ KCl/ L = \frac { 0.14 \ mol \ KCl}{x}$

We are solving for x, so we must isolate the variable. First, cross multiply. Multiply the first numerator and second denominator, then the first denominator and second numerator.

$\frac {1.8 \ mol \ KCl/L}{1} = \frac{0.14 \ mol \ KCl}{x}$

$1.8 \ mol \ KCl/ L *x = 1*0.14 \ mol \ KCl$

$1.8 \ mol \ KCl/ L *x = 0.14 \ mol \ KCl$

Now x is being multiplied by 1.8 moles of potassium chloride per liter. The inverse operation of multiplication is division, so we divide both sides by 1.8 mol KCl/L.

$\frac {1.8 \ mol \ KCl/ L *x}{1.8 \ mol \ KCl/L} = \frac{0.14 \ mol \ KCl}{1.8 \ mol \ KCl/L}$

$x= \frac{0.14 \ mol \ KCl}{1.8 \ mol \ KCl/L}$

The units of moles of potassium chloride cancel.

$x= \frac{0.14 }{1.8 L}$

$x=0.07777777778 \ L$

The original measurements of moles and molarity have 2 significant figures, so our answer must have the same. For the number we found, that is the thousandth place. The 7 in the ten-thousandth place tells us to round the 7 up to a 8.

$x \approx 0.078 \ L$

There are approximately <u>0.078 liters of solution.</u>

5 0

3 years ago