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3 years ago

BRAINLIEST + 20 POINTS

Chemistry

2 answers:

vichka [17]3 years ago

8 0

Answer:

The answer is C (filler)

Zina [86]3 years ago

4 0

Answer: b hope im not wrong

Explanation:

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What is the mass of arsenic that is contained in a 50.0 g sample if the concentration is 5 ppm?

faltersainse [42]

Answer: The mass of arsenic found in the sample is 0.25 mg

Explanation:

ppm is the amount of solute (in milligrams) present in kilogram of a solvent. It is also known as parts-per million.

To calculate the ppm of oxygen in sea water, we use the equation:

$\text{ppm}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^6$

Both the masses are in grams.

We are given:

Concentration of arsenic = 5 ppm

Mass of sample = 50 g

Putting values in above equation, we get:

$5=\frac{\text{Mass of arsenic}}{50g}\times 10^6\\\\\text{Mass of arsenic}=\frac{5\times 50}{10^6}=0.00025g=0.25mg$

Conversion factor used: 1 g = 1000 mg

Hence, the mass of arsenic found in the sample is 0.25 mg

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3 years ago

Which of the following is a chemical change?

Scorpion4ik [409]

Answer: D, splitting water into hydrogen and oxygen is a chemical change.

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2 years ago

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When a magnet spins within a coil of wires, what is produced?

Andrei [34K]

Decreasing the turns of wire

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What happens when a solid compound dissolves in water?

IRINA_888 [86]

It becomes a liquid with the water

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2 years ago

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A chemist dissolves 867. mg of pure barium hydroxide in enough water to make up 170. mL of solution. Calculate the pH of the sol

Ilya [14]

Answer: The pH of the solution is 11.2

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

$Molarity=\frac{n\times 1000}{V_s}$

where,

n = moles of solute

$V_s$ = volume of solution in ml

moles of $Ba(OH)_2$ = $\frac{\text {given mass}}{\text {Molar mass}}=\frac{0.867g}{171g/mol}=0.00507mol$ (1g=1000mg)

Now put all the given values in the formula of molality, we get

$Molarity=\frac{0.00507\times 1000}{170}$

$Molarity=0.0298$

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration.

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

$Ba(OH)_2\rightarrow Ba^{2+}+2OH^{-}$

According to stoichiometry,

1 mole of $Ba(OH)_2$ gives 2 mole of $OH^-$

Thus 0.0298 moles of $Ba(OH)_2$ gives = $\frac{2}{1}\times 0.0298=0.0596$ moles of $OH^-$

Putting in the values:

$pOH=-\log[0.0596]=2.82$

$pH+pOH=14$

$pH=14-2.82$

$pH=11.2$

Thus the pH of the solution is 11.2

8 0

3 years ago