Answer:Since 1743 the Celsius scale has been based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm pressure. Prior to 1743 the values were reversed (i.e. the boiling point was 0 degrees and the freezing point was 100 degrees).
Explanation: i no it
Explanation:
Carbon exists in several isotopes. ... Carbon has the atomic number of 6 which means that all isotopes have the same proton number. However, the number of neutrons is different, thus giving different mass numbers. Carbon-12 has 6 neutrons, carbon-13 has 7 neutrons, and carbon-14 contains 8 neutrons.
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 %
