Answer: The concentration of unknown sample is 1.8 mg/ml
Explanation:
According to the dilution law,
where,
= concentration of stock solution = ?
= volume of stock solution = 0.25 ml
= concentration of diluted solution = 0.45 mg/ml
= volume of diluted solution = (0.25+0.75) ml = 1.00 ml
Putting in the values we get:
Therefore, concentration of unknown sample is 1.8 mg/ml
The volume of 6.40 grams of O₂ gas at STP is 4.48L (option A). Details about volume can be found below.
<h3>How to calculate volume?</h3>
The volume of a gas can be calculated using the following formula:
p = m/v
Where;
- p = density
- m = mass
- v = volume
According to this question, the mass of O₂ gas at STP is 6.40 grams. The density of the gas at STP is 1.43 g/L.
1.43g/L = 6.4g/V
Volume of O2 = 6.4 ÷ 1.43 = 4.48L
Therefore, the volume of 6.40 grams of O₂ gas at STP is 4.48L.
Learn more about volume at: brainly.com/question/1578538
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