The chart shows the bids provided by four contractors to complete a job. Which contractor is the most cost-effective? Joshua Carmen Dante Alicia

Chart for question attached

Joshua

Explanation:

By cost-effective here, we mean the contractor that does the job best at the shortest time and lowest money cost. To get this, we calculate total cost for each contractor and then consider time for completion of the job:

Joshua charges $25 per hour for 5 hrs

Carmen charges $20 per hour for 7 hrs

Dante charges $30 per hour for 6 hrs

Alicia charges $20 per hour for 8 hrs

Joshua's cost= $25×5=$125 in 5 hours

Carmen's cost = $20×7= $140 in 7 hours

Dante's cost= $30×6=$180 in 6 hours

Alicia's cost= $20×8= $160 in 8 hours

From the above we can see that Joshua is the most cost-effective contractor given that he completes the job in less time and with less money.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"

a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o