3. you are a nascar pit crew member. your driver is leading the race with 20 laps to go. he just finished
a pit stop which included refueling. you know that 3500g of fuel are in the tank. will your driver be able
to finish the race without another pit stop? if he can drive 20 more laps on the tank of fuel, he can win the
race. how (grams) much oxygen will the driver use during this time.

All of the following are part of the biosphere except

7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation. 8. when a 2.5 mol of sugar (c12h22o11) are added to a certain amount of water the boiling point is raised by 1 celsius degree. if 2.5 mol of aluminum nitrate is added to the same amount of water, by how much will the boiling point be changed? show all calculations leading to your answer or use 3 – 4 sentences to explain your answer. 9. if 5.40 kcal of heat is added to 1.00 kg of water at 100⁰c, how much steam at 100⁰c is produced? show all calculations leading to an answer. 10. the freezing of water at 0⁰c can be represented as follows: h2o (l) ↔ h2o(s) the density of liquid water is 1.00 g/cm3. the density of ice is 0.92 g/cm3. in 3 – 4 sentences explain why applying pressure causes ice to melt.

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?