It is the concept of surface tension that helps the coin to float on the top of the water in the glass. The surface tension acts just opposite to the gravitational force and that is why when any metal placed in the water it will float and come on the surface. Hope this helps!
Answer:
Percent yield = 22.8 %
Explanation:
Step 1: Data given
Numbers of moles copper = 0.0970 moles
Mass of copper(I) sulfide = 1.76 grams
Step 2: The balanced equation
2Cu + S ⇒ Cu2S
Step 3: Calculate moles of Cu2S
For 2 moles Cu we need 1 mol S to produce 1 mol Cu2S
For 0.0970 moles Cu we'll hace 0.0970 / 2 = 0.0485 moles
Step 4: Calculate mass of Cu2S
Mass Cu2s = moles Cu2S * molar mass Cu2S
Mass Cu2S = 0.0485 moles * 159.16 g/mol
Mass Cu2S = 7.72 grams
Step 5: Calculate percent yield
Percent yield = (actual yield/ theoretical mass) * 100%
Percent yield = (1.76 grams / 7.72 grams)*100%
Percent yield = 22.8 %
Answer:
It would be the first one
Explanation:
According the solubility rules if SO4 is with Pb then it is insoluble.
Answer:
1.61 × 10⁶ kJ
Explanation:
The human burns energy so as to be healthy.
The amount of energy burnt per day by an adult human is 2 × 20³ kcal per day. Since there is 24 hours in a day, the amount of energy burnt per hour is 2 × 20³ × 24 = 48 × 20³ kcal per hour.
The conversion rate of kcal to kJ is 1 kcal = 4.184 kJ. Therefore converting the kcal per hour to kJ per hour gives:
48 × 20³ × 4.184 = 200.882 × 20³ kJ = 1.61 × 10⁶ kJ
