Physics, 31.10.2019 01:31, quece233

Iced tea is made by adding ice to 1.8 kg of hot tea. the hot tea is initially at 80˚c. 1.4 kg of ice, initially at –10˚c, is placed in the tea and allowed to come to thermal equilibrium inside a thermos. you can assume the hot tea is essentially all water. what will be the final temperature of this system?

Answers: 1

Show answers

Answers

answered: danielle4124

$T_f=7.6619^\circ C$

Explanation:

Given:

mass of the tea, m_t=1.8kg

temperature of the tea, $T_t=80^\circ C$ mass of ice, m_i=1.4kg

temperature of the ice, $T_i=-10^\circ C$

We, know

specific heat of tea(water), $c_t=4.184 J.kg^{-1}.K^{-1}$ specific heat of ice, $c_i=2108 J.kg^{-1}.K^{-1}$ Latent heat of fusion of ice, $L_i=336000 J.kg^{-1}$

Heat required for warming of ice upto 0°C from -10°C

$Q_i=m_i\times c_i\times \Delta T$

$Q_i=1.4\times 2108\times 10$

Q_i=29512 J

Heat released during the cooling of tea upto 0°C from 80°C

$Q_t=m_t\times c_t\times \Delta T$

$Q_t=1.8\times 4184\times 80$

Q_t= 602496 J

∵ Q_t Q_i

∴The heat from the quantity that remains after bringing the ice to 0°C will be used for melting the ice.

Heat remaining afterthis process:

Q_0=(Q_t -Q_i) = 572984 J

Amount of heat energy required by the total mass of ice to melt at 0°C:

Q_L=m_i.L_i

$Q_L=1.4\times 336000$

Q_L=470400 J

Now, the remaining of the heat will be used to raise the temperature of the tea (water) from 0°C to a higher temperature.

Heat remaining after melting the total ice into water at 0°C which will increases the temperature of water:

Q_w= Q_0-Q_L

Q_w=572984-470400

Q_w=102584 J

Now, the final temperature of the tea(water)rising from 0°C:

∵whole ice(along with tea) is now water with initial temperature T_i = 0°C

$Q_w=(m_i+m_t)\times c_t\times(T_f-T_i)$

where:

T_f = final temperature

$102584=(1.8+1.4)\times 4184\times (T_f-0)$

$T_f= \frac{102584}{3.2\times 4184}$

$T_f=7.6619^\circ C$

answered: Guest

0.3x0.21x0.08kg=mass 1 sheet

mass 500 = 500xmass 1

volume pile = 0.3x0.2x0.048

density=mass/volume= 500xmass 1/0.3x0.2x0.048

v patient student

answered: Guest

elly's long hair:

a. if the salon only takes cash, then this isn't the problem. it doesn't matter how much she has in her checking account. she can't get a haircut until she has the cash.

b. if she has overdraft protection, then there's no problem. she can go ahead and write a check that her account can't cover, then sometime later, pay the bank some outrageous usury for loaning her a few bucks for a few days, but with beautiful hair.

c. if elly has some principles, and doesn't want to write a bad check, then now she has a problem. her desire for the new hairstyle is in conflict with her honesty and integrity.

d. if the bank will not process a check she writes, then even if she had a million $$ in her account, she couldn't use any of it. the amount she has in her account is not the problem. and if i may suggest, she might as well close her checking account, and put the money where it'll work for her. it's not doing her a bit of good in a checking account, since she can't write any checks.

justin can't pay the full balance:

a. he can't even handle the credit limit he has now. under no circumstances should he ask for a higher limit.

b. he can ask for the grace period to be extended. but that's no solution, the bank will almost certainly refuse anyway, and there are much better options. he knew the rules of his credit card when he started using it.

c. he definitely should pay the interest on the balance, plus as much of the balance as he can cover at the same time.

d. he definitely should pay the minimum otherwise they could shut down his card. he should also pay as much more as he possibly can. he should also remember the awkward situation he's in, stop buying stuff on credit that he can't afford, and avoid adding any more debt.

i'd say that justin's best best option isn't on this list of choices. what he has to do: pay as much as he can at least the minimum payment plus as much more as he can and then avoid adding more debt.