dissolving sugar in water is a physical change but heating sugar to form a caramel is a chemical change .Explain
1 answer:
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Answer:
61.5096 %
Explanation:
Let the amount of gold in the jewelry = x g
Let the amount of silver in the jewelry = y g
Total mass of jewelry = 9.85 g
So,
x + y = 9.85 g .................................1
Density = Mass / Volume
Given that:
Density of gold = 19.3 g/cm³
Thus, volume is:
Volume = Mass / Density = x / 19..3 cm³
Given that:
Density of silver = 10.5 g/cm³
Thus, volume is:
Volume = Mass / Density = y / 10.5 cm³
The total volume of the jewelry = 0.675 cm³
So,
Or,
10.5 x + 19.3 y = 136.78875 ................2
Solving 1 and 2, we get that:
<u>x = 6.0587 g</u>
<u>y = 3.7913 g</u>
So, mass % of gold:
<u>Mass % = (6.0587 / 9.85)×100 = 61.5096 %</u>
Answer:
1335.12 mL of H2O
Explanation:
To calculate the mililiters of water that the solution needs, it is necessary to know that the volume of the solution is equal to the volume of the solute (NaOH) plus the volume of the solvent (H2O).
From the molarity formula we can first calculate the volume of the solution:
The volume of the solution as we said previously is:
Solution volume = solute volume + solvent volume
To determine the volume of the solute we first obtain the grams of NaOH through the molecular weight formula:
Now with the density of NaOH the milliliters of solute can be determined:
Having the volume of the solution and the volume of the solute, the volume of the solvent H2O can be calculated:
Solvent volume = solution volume - solute volume
Solvent volume = 1429 mL - 93.88 mL = 1335.12 mL of H2O