The answer is D.
The atomic number stands for the number of protons in each element. The number of protons is what is unique to each element. The number of neutrons varies; this is what isotopes are. The number of protons being the atomic number explains why the atomic number is an identifying characteristic of each element.
Amount of silver nitrate taken = 269.μmol 
Volume of the solution = 300. mL
Concentration of a solution is generally expressed in terms of molarity. Molarity is defined as the moles of a substance present per liter of the solution.
We want the concentration in millimoles/L.
Converting μmol to millimol solute:
μ
= 0.269 millimol
Volume from mL to L: 
Therefore concentration of the chemist's solution = 
<span>C7H16 + 11O2 ------> 7CO2 + 8H2O
</span><span>C- 7 C- 7
H- 16 H -8*2=16
O -11*2 =22 O - 7*2 +8 =14+8=22</span>
Answer: A solid has a defined shape and volume. A common example is ice.
A liquid has a defined volume, but can change state. An example is liquid water.
A gas has neither a defined shape nor volume. Water vapor is an example of a gas
The answer is iron III sulfate
