Use a periodic table. Count the exponent for your atomic number. So, 1s2 2s2 2p5= Fluorine
1s2 2s2 2p6 3s2 3p5= Chlorine
1s2 2s2 2p6 3s2 3p6 4s2 3d6= Iron
<span>The first method to determine the chemical composition of a substance in space was using light. By determining red shift in the observed spectrum of light they could determine the elements they were observing. Different elements change the way light behaves and from this scientists can determine the makeup of things such as stars and nebulas.</span>
I think B. because of this picture??
CaCO₃ + 2HCl = CaCl₂ + CO₂ + H₂O
n(CaCO₃)=m(CaCO₃)/M(CaCO₃)
n(CaCO₃)=13.00/100.09=0.1299 mol
Δm=13.00+52.65-60.32=5.33 g
m(CO₂)=5.33 g
n(CO₂)=5.33/44.01=0,1211 mol
w=0.1211/0.1299=0,9323 (93.23%)
