Answer:
what is the valency of carbon in CH3-CH3,CH2=CH2AND HC=CH. The valency of carbon in all the given structures is fourplanation:
Carbon can form a wide variety of organic compounds because:
Each carbon atom covalently bonds with toms of carbon, hydrogen oxygen, and nitrogen
A carbon atom can have 4 single valence electrons around it. This allows it to form covalent bonds with many different atoms.
You have to use density=mass/volume formula:

Solve for x and you get
2282.75 grams
There are 18 Elements in the fifth period.
Remembering the equation Q=MCdeltaT where
q=is the amount of heat energy
M=mass
C=specific heat
deltaT= change in temperature
Therefore, using the equation we can substitute values and solve for q.
Q= (15 grams) (0.129 J/(gx°C))(85-22)
Q=(15) ((0.129 J/(gx°C)) (63)
Q=121.9 Joules
The energy needed to raise the temperature of 15 grams of gold from 22 degrees Celsius to 85 degrees Celsius is then 121.9 Joules or 122 Joules (if rounded up).