The tilt of the earth provides the earth with seasons. As the earth revolved around the sun different portions (northern or Southern Hemisphere) is exposed more directly to the suns radiation, thus it is hotter in those regions. (Why the United States experiences winter in December but Australia experience summer in December.)
Answer:
a) 600 J
b) 75 W
Explanation:
Force= 400 N, distance = 150 cm = 1.5 m, time= 8s
a) Work is the product of force acting on an object and distance (or displacement). The S.I unit of work is the joules.
Work = force × distance = 400 × 1.5 = 600 J
b) Power is the amount of energy transferred per unit time. It is the ratio of work to time. The S.I unit of power is watt
Power = work/time = 600 / 8 = 75 W
The reaction creates dihydrogen, hence if it's uncontrolled it could lead to potentially dangerous amounts of gas being released at once.
Answer:
C. To determine how efficient reactions are.
D. To determine how much reactant they need.
Explanation:
When you are doing a reaction, you are hoping for a percent yield to close of 100%. You make the reaction and determine how many product you obtain. If you know the percent yield of a reaction you can calculate the amount of reactant you need to obtain a determined amount of product.
Having this in mind:
A. To balance the reaction equation. false. To calculate percent yield you need to balance the reaction before. You don't use percent yield to balance the reaction
B. To determine how much product they will need. false. You determine how much product you obtain after the reaction. How much product you need is independent of percent yield
C. To determine how efficient reactions are. true. A way to determine efficience of a reaction is with percent yield. An efficient reaction has a high percent yield.
D. To determine how much reactant they need. true. If you know percent yield of a reaction you can know how many reactant you must add to obtain the amount of product you want.
