B is the answer. For an equation to be balanced there must be the same amount of each element on the two sides. The only one where this is the case is B.
Explanation:
Percentage ethylene by weight = 57%
Percentage propylene by weight = 43%
Suppose in 100 grams of polymer:
Mass of ethylene = 57 g
Mass of propylene = 43 g
Moles of ethylene = 
Moles of propylene = 
1 mole =
molecules/ atoms
Units of ethylene = 
Units of propylene = 
a) Fraction of ethylene units:

b ) Fraction of propylene units:

Answer:
3 m/s
Explanation:
24 m/s over 8 seconds would be 24/8 making it be 3 m/s avg
@pandamille help her please!!!!
The balanced chemical reaction for the described reaction above is,
Na2CO3 + 2HCl ---> 2NaCl + H2CO3
From the reaction, 1 mole of Na2CO3 is needed to produce 2 moles of NaCl. In terms of mass, 106 grams of Na2CO3 are needed to produce 116.9 grams of NaCl. From this,
(23.4 g NaCl) x (106 g Na2CO3 / 116.9 NaCl = 21.22 g Na2CO3
Thus, approximately 21.22 g Na2CO3 is needed for the desired reaction.