It’s b. The earth is heated by energy from the sun The sun gives off radiation and heat in the form of ultraviolet rays which is what causes the earth to heat :)
It seems your question is incomplete, however, that same fragment has been found somewhere else in the web:
" <em>A chemist prepares a solution of silver nitrate (AgNO3) by measuring out 85.g of silver nitrate into a 150.mL volumetric flask and filling the flask to the mark with water.</em>
<em>Calculate the concentration in mol/L of the chemist's silver nitrate solution. Be sure your answer has the correct number of significant digits.</em> "
In this case, first we <u>calculate the moles of AgNO₃</u>, using its molecular weight:
85.0 g AgNO₃ ÷ 169.87 g/mol = 0.500 mol AgNO₃
Then we<u> convert the 150 mL of the volumetric flask into L</u>:
Polarity is classified by the difference in two or more atoms that is the electronegativity value (EN) En for Fluorine =4.0, Bromine=2.96 Chlorine =3.16 Hydrogen=2.1 for the molecules HF=4.0-2.I=1.9 HCl=3.16-2.1=1.06 Hbr=2.96-2.1=0.86 Hi=2.66-2.1=0.56 H2=2.1-2.1=0 from the EN value above HF has the mast highest value of EN hence it is the most polar.
