I believe it’s D because phosphorus has the mass of 30.9.
Answer:
Rubidium Sulfide
Explanation:
The chemical name for Rb2S is Rubidium Sulfide
The density of the block will be "7.11 gm/cm³". A further explanation is provided below.
Given values are:
Density of iron,
Mass of block of metal,
Volume of block,
By using the formula,
→ 
then,
→ The density of block will be:
= 
= 
= 
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False
Explanation: Carbon is the central atom which has valency of 4 and can form 4 bonds to complete its octet. Each chlorine has valency of 1 and can form only one bond to complete its octet. Thus carbon can bond with four chlorine atoms through sharing of electrons to form four single bonds. Thus it cannot contain a double bond.
7. Large Intestine and chemical digestion
8.stomach
9.capillaries
4.neurons
hopefully this is correct