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 %
Explanation:
What is motion? define friction.
Friction is the resistance to motion of one object moving relative to another. It is not a fundamental force, like gravity or electromagnetism. Instead, scientists believe it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
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Answer:
E. 
Explanation:
From the ideal gasses equation we have:
PV=nRT
where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature.
The number of moles is also expressed as: 
If replacing this in the ideal gasses equation we have:
If we pass V to divide, we have:
And the density d = 
, so replacing, we have:
Solving for d, we have:
Now we have to be sure that we have the correct units, so we need to convert the units for pressure and temperature:
-Convert P=98kPa to atm
-Convert T=-25.2°C to K
Finally we can replace the values in the equation:
C. energy is released
(Forming bond is exothermic)
Answer:
A
Explanation:
If a convergent boundary involves a continental landmass and an ocean basin, a subduction zone forms. Subduction occurs where a plate moves underneath the other.
