Arthur is testing how well various types of disinfectants can kill e. coli bacteria. he starts with a petri dish that is covered with e. coli. he puts exactly one milliliter of each different disinfectant at a different location on the petri dish. if a disinfectant works, it will eliminate the bacteria in the area in which it was placed. two days later, arthur will measure the amount of bacteria that has been cleared out by each disinfectant. which of the following is a variable in this experiment?

a. the type of disinfectant used

b. the type of bacteria used

c. the petri dish used

d. the length of time that the disinfectant is used

  1.the balanced   chemical equation is as below

cu +   2 ag(no)₃ → cu(no₃)₂   +2 ag

2.the   much silver   produced   is   50.9 g

step 1: find the   moles of cu

moles =   mass÷   molar mass

  from periodic table the molar mass of cu = 63.5 g/mol

moles is therefore = 15.00 g÷ 63.5 g/mol = 0.236   moles

step 2: use the mole ratio to determine the   moles of ag

from equation above   cu: ag   is 1: 2

therefore the moles of ag   =0.236   moles   x 2/1 =0.472   moles

step 3: find the mass   of ag

mass = moles x molar mass

from periodic table   the molar mass of ag =107.87 g/mol

mass   = 0.472   moles x 107.87 g/mol = 50.9 g

3.   the   much   silver   collected worth is   1.797 oz

  convert   50.9 g   to oz

that is   1 gram = 0.0353 oz

          50.9 grams =?   oz

by cross multiplication

={(50.9 grams x 0.0353 oz) / 1   gram}   =1.797 oz