monthly service charge is flat. you have to pay it no matter how many therms you use.
since you've used only 25 therms, they'll charge you $0.6686/therm
so, total charge for using 25 therms in one month
= 8.8 + 25*0.6686=16.715+8.8 = 25.52
What is the charge for using 45 therms in one month?
45 = 25 + 20
so for first 25 therms they'll charge u .6686/therm, and rest of the 20 they'll charge u 0.85870/therm
8.8 + 25*.6686 + 20*.85870
25.52+17.174 = 42.694
In order to find the number of moles with a given mass of Helium, we need to use its molar mass, which is 4.0026g/mol, therefore we will have:
4.0026g = 1 mol of Helium
91.5g = x moles of Helium
x = 22.86 moles of Helium in 91.5 grams
The correct options are as follows:
1. A.
A synthesis reaction is a type of reaction in which two or more reactants combine together to form only one product. Synthesis reaction always release energy in form of light and heat, therefore, they are usually exothermic reactions. In the option given in A, nitrogen and nitrogen combine together to form ammonia; this is a synthesis reaction.
2. D
A radioactive half life refers to the amount of time it will take for half of an original radioactive isotope to decay.
In the question given above, the half life of the element is 1000. Thus, in 1000 years only half of the original amount will remain. In another 1000 years only 1/4 of the original amount will remain and in another 1000 years only 1/8 of the original amount will remain. Therefore, it will take 3 half lives before 1/8 of the original sample remain.<span />
Three of the functions of proteins are as antibodies, as enzymes and as messengers. As antibodies, they protect the cells from diseases ie they fight diseases. As enzymes, they regulate the chemical reactions within cells, and thirdly they transmit signals as messengers such as hormones do in co-ordinating biological processes. Proteins are so diverse because of their unique 3-D structures which their polymers form from the 20 amino acids available as their building blocks.
