lilai3
  • lilai3
WILL REWARD MEDAL/ FAN!!((((: The fuel value of peanuts is 25 kj/ gram. If an average adult needs 2800 kilocalories of energy a day, what mass of peanuts would meet an average adult's energy needs for the day? Assume all of the fuel value of the peanuts can be converted to useful energy.
Mathematics
  • Stacey Warren - Expert brainly.com
Hey! We 've verified this expert answer for you, click below to unlock the details :)
SOLVED
At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga. Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus. Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
chestercat
  • chestercat
I got my questions answered at brainly.com in under 10 minutes. Go to brainly.com now for free help!
UnkleRhaukus
  • UnkleRhaukus
1 adult's energy requirement = 2800 kc/day how many kilo calories are required "for the day"?
lilai3
  • lilai3
2800?
UnkleRhaukus
  • UnkleRhaukus
yes,

Looking for something else?

Not the answer you are looking for? Search for more explanations.

More answers

UnkleRhaukus
  • UnkleRhaukus
how many joules of energy, is 1 kilocalorie?
lilai3
  • lilai3
4.184
UnkleRhaukus
  • UnkleRhaukus
so how many joule of energy is 2800 kilocalories, i.e. 2800 [kc] x 4.184 [j/kc] =
lilai3
  • lilai3
11715.2 joules?
UnkleRhaukus
  • UnkleRhaukus
So , we have a requirement of 11715.2 [ j ] . And, we know the fuel value of peanuts is 25 [ kj / g ]
lilai3
  • lilai3
yeah
UnkleRhaukus
  • UnkleRhaukus
wait a minute 4.184 kilojoules* of energy, is 1 kilocalorie!
UnkleRhaukus
  • UnkleRhaukus
so we have 11715.2 [kj ] .
lilai3
  • lilai3
yeah. how do you set it up?
UnkleRhaukus
  • UnkleRhaukus
food value [ kj/g ] = energy [ kj ] / mass [ g ] so mass [ g ] = energy [ kj ] / food value [ kj/g ]
lilai3
  • lilai3
mass = 4.184 kj / 25?
lilai3
  • lilai3
oh and then you just divide it and the answer will be in grams?
UnkleRhaukus
  • UnkleRhaukus
yeah , what do you get?
UnkleRhaukus
  • UnkleRhaukus
doe it seem like a reasonable result?
lilai3
  • lilai3
0.17 grams
lilai3
  • lilai3
is that correct?
UnkleRhaukus
  • UnkleRhaukus
wait, a minute
UnkleRhaukus
  • UnkleRhaukus
mass of peanuts [g] = 11715.2 [kj ] / 25 [kj/g]
UnkleRhaukus
  • UnkleRhaukus
the energy required is the 11715.2 [kj]
lilai3
  • lilai3
468.61 grams?
lilai3
  • lilai3
that feels more correct than the answer I got less than 1 last time
UnkleRhaukus
  • UnkleRhaukus
yeah, about half a kilo seems reasonable to me
lilai3
  • lilai3
so basically we just had to convert kilocalories to kilojoules to get the mass?
UnkleRhaukus
  • UnkleRhaukus
first, we found the energy required in the time considered (one day) then we converted the energy from kilocalories to kilojoules and then from kilojoules, we used the fuel value of peanuts to find the mass of peanuts that provides this energy
lilai3
  • lilai3
Oh, okay. I see how it relates to the problem now. Thanks.
lilai3
  • lilai3
I have one more if you don't mind.
lilai3
  • lilai3
The specific heat of aluminum is 0.902 joule / g x Celsius and that of silver is 0.235 joules / grams x Celsius. You have two spoons of equal masses. One is made of aluminum and other silver. Which spoons would increase in temperature faster in a pot of hot soup? Why?
lilai3
  • lilai3
This one is so hard
lilai3
  • lilai3
Do you think you can help me with this one?
UnkleRhaukus
  • UnkleRhaukus
if we look at the units of specific heat capacity, that is \([\frac{\textrm j}{\text g\,°\text C}]\)
lilai3
  • lilai3
yep
UnkleRhaukus
  • UnkleRhaukus
the units say the specific heat capacity is: the energy [joules] to heat a mass [grams] by a temperature [°C]
lilai3
  • lilai3
yeah, i understand that.
UnkleRhaukus
  • UnkleRhaukus
so which spoon takes the lesser amount energy transfer to heat up
lilai3
  • lilai3
Would it be the silver? Since 0.235 is less than 0.902 joules? So then it would take less amount for energy to heat?
UnkleRhaukus
  • UnkleRhaukus
yep, from experience, we know that metals are good conductors of heat [ metals feel very cold on a normal day, or burn us quickly if they are hot and we touch them ]
UnkleRhaukus
  • UnkleRhaukus
silver is a 'better' metal than aluminium more shiny and much better conductor
lilai3
  • lilai3
so the aluminum will be faster to heat up in a pot of hot soup because 0.902 joules is greater than 0.235 joules.
UnkleRhaukus
  • UnkleRhaukus
nope the Al takes more energy to transfer temperature
UnkleRhaukus
  • UnkleRhaukus
(which takes more time)
lilai3
  • lilai3
wait so the higher the joule, the more energy it requires for it to heat something up?
UnkleRhaukus
  • UnkleRhaukus
more to heat it up AND more to cool it down
lilai3
  • lilai3
so silver will increase the temperature faster due to it's smaller joule, which makes the process of heating faster than the alumiunum?
UnkleRhaukus
  • UnkleRhaukus
the mass are the same , the comparison is the joule to degree ratio
lilai3
  • lilai3
So my answer is going to be The silver spoon will increase in temperature faster than aluminum since silver has a smaller joule. The higher the number of joules, the more energy it requires to heat up something.
lilai3
  • lilai3
is it okay? should i add anything?
UnkleRhaukus
  • UnkleRhaukus
The silver spoon will increase in temperature faster than aluminium spoon, since the masses are the same, and silver has a smaller specific heat than aluminium: The greater the specific heat, the more joules of energy must transfer to the spoon; the more time is required for soup to heat the spoon by a given amount.

Looking for something else?

Not the answer you are looking for? Search for more explanations.