This may help you
Use an arbitrary mass, 100 g is an easy number to work with.
60% of 100 g is 60 g, there are two A's. Each A is 30 g
40 g is B, and there is only one, so B is 40 g.
<span>A<span>B2</span></span>, would have a mass of 30 g + 2*40 g = 110 g
The new percent by mass composition of A is: <span><span><span>30g</span><span>110g</span></span>∗100%=27.3%</span>
The new percent by mass composition of B is: <span><span><span><span>80g</span><span>110g</span></span>∗100%=72.7%</span></span>
2 Al + 6 HCl → 2 AlCl₃ + 3 H₂ (single displacement)
Ca + Br₂ → CaBr₂ (synthesis)
4 NH₃ + 5 O₂ → 4 NO + 6 H₂O (combustion)
2 NaCl → 2 Na + Cl₂ (decomposition)
FeS + 2 HCl → FeCl₂ + H₂S (double displacement)
single displacement - is a chemical reaction of the following type: A + BC → AC + B
double displacement - is a chemical reaction of the following type: AB + CD → AC + BD
synthesis - the chemical product is obtained by combining in a synthesis the constituent elements
combustion - usually a exothermic reaction of a particular compound with oxygen
decomposition - degradation of a compound in simpler elements
Three groups
gases, metals, metalliods/nonmetals
It is the mass of one mole of the substance.