Answer:
Here... Since there is excess HCl, you know the Zinc will be the limiting reagent. I was able to create the reaction equation based on the info you gave: Z + 2HCl ----> ZCl2 +2H. Now, in order to find the theoretical yield of ZCl, you need to convert Zinc from grams to moles. Do this by dividing by its molar mass (65.38), thus: 3.68 (g) / 65.38 (g/mol) = 0.056286... moles.
Now, using the balanced equation we made earlier, we see that 1 mole of Zinc creates 1 mole of ZCl2. Thus our ratio is 1:1. This makes the next step easy. Since it is 1:1, we multiply the number of moles we have of Zinc (0.056286...) by the number of moles it will create of ZCl (1). (0.056286)(1) = 0.056286 moles ZCl. Now convert this to grams by multiplying by its molar mass (136.28) and you get 7.67 grams. This is your theoretical yield. The percent yield is found by dividing the actual amount obtained (7.12 g.) by the theoretical yield (7.67 g.) then multiply that by 100%. When this is done, your Percent Yield is about 92.8%
Answer:
The mean value theorem tells us the average velocity must be between the minimum velocity and the maximum velocity. The only way it can be either the minimum or the maximum is if velocity is constant. So of course instantaneous velocity can be greater and can be less.
Explanation:
Answer: 8.7 grams
Explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number 
of particles.
To calculate the moles, we use the equation:
As oxygen is in excess, Aluminium is the limiting reagent and limits the formation of products.
According to stoichiometry:
4 moles of aluminium give = 2 moles of 
Thus 0.17 moles of aluminium give=
Mass of 
Thus the mass of is 8.7 grams
Stratosphere:) hope this helped
