Question
Use the following heating curve for water to answer the questions5100 L 50energy added (cal)Label each pracess number whether its a heating step ar phase change step: For each process, also indicate whether we would apply the heat equatian q mCAT or enthalpy 4H to determine amount of energy required:1. step 1:Select ]equation used:Select _2. step 2:Select ]equation used:Select ]3. step 3:Select ]equation used:Select ]4. step 4Select ]equation used:Select ]5. step 5:Select ]equation used:Select ]
Use the following heating curve for water to answer the questions 5100 L 50 energy added (cal) Label each pracess number whether its a heating step ar phase change step: For each process, also indicate whether we would apply the heat equatian q mCAT or enthalpy 4H to determine amount of energy required: 1. step 1: Select ] equation used: Select _ 2. step 2: Select ] equation used: Select ] 3. step 3: Select ] equation used: Select ] 4. step 4 Select ] equation used: Select ] 5. step 5: Select ] equation used: Select ]
Answers
In the questions that follow, you may need to use the specific heat capacities shown in Table 2.1 on page 163 and the latent heats shown in Table 2.2 on page 165. (a) How much thermal energy is required to warm $1.0 \mathrm{kg}$ ice initially at $-10^{\circ} \mathrm{C}$ to ice at $0^{\circ} \mathrm{C} ?$ (b) How much thermal energy is required to melt the ice at $0^{\circ} \mathrm{C}$ (c) How much thermal energy is required to further increase the temperature of the water from $0^{\circ} \mathrm{C}$ to $10^{\circ} \mathrm{C}$. (d) In which stage (warming the ice, melting the ice, warming the water) is the thermal energy requirement largest?
In the given question we have a container And three things are added. Number one, Okay gram of ice. Which is a zero DB. Number two is this dig them of 15. Which is that readily associates. And the number 30s 1 50 g of water. What? Which is that? So the question is asking, what is a final temperature of all these mixtures? So first of all, what is the total mass? Mm. It is 100 plus 50 plus 150. That is £300. Mm. Okay now let's talk about the energy balance. Let's see that 50 grand of On history won 50 g of water Is at zero level. It is a residence. Okay, so this is the difference. Now how much the ice will gain and how much the esteem will lose energy. So delta you can see delta H plus high esteem, how much it is more than water. It is. It will be called to. The value is 100 g sorry, 50 g of Esteem and two C. V. Delta T. Into C. V. Which is 4.2 Illogical. In two Delta P. Which is $60. 40 70 degrees From 30 200. Yes. How much the latent energy is? Will we? 2257. It is the latent energy specific latent hit specific. Layton. Yeah. In two mm. Mass. That is 51. So converting it into kg. We'll get 1-0. Right? It will be also .05. Okay mm. Zero fight. So finally see what is a value. So this total value comes out to be 1 to 7 0.55 Doesn't he loves you make No. We will calculate delta H minus or ice with the same reference that is starting with associates of water. So it will be and seven delta T. Last M. S. So it will be 0.1 and two 4.2230. As it is going some 320 less. 0.1 into who's leading it Which will lose 3 3 4.4. The final value becomes 46.04. Okay so we are seeing that this value the steam part has is more than this negative part. We can let's say minus sign because it is in a reference to water. So now final H final hit Value is 1 27.55 miners. But the 6.04 that becomes 81.51. So this is the final amount of additional energy we have. Final additional energy. Okay. No we know that our new must is a combination of both ice water and this time. So now our new mass has become 50 plus 100 15 plus 100. This all values attached. So it will be 300 grounds. So we can say zero 10 kg. No we will increase the final for it. We will use M c v Delta T. We have assumed that whole system. Is that 30°. So how much the additional heat will change the temperature. Additionally, it was 81.51 and he snapped it. So our mask is finally 0.3 the value of CVS 4.2. And we have the LDA which is t minus party. That's the question, 81.51. So being minus 30 is approximately coming 65 0.4. So our the final will be 95.4°. So yes, this near so final temperature is nearly equal to 95 points for the senses.
The given system. We have calorie meter, a heater and some liquid. Okay, So it is a closed system, closed system. So we can say energies consult. Yes and so no. What are the units given? Is This heater is producing 20 watt for three minutes. So we will write as delta X. Generated by hater equals two 20 word for three minute, which is 20 to 60 into three jewels, which will be 36 In 202. Let it be in this way. Now the heat gained white calorie meter calorie meter. His m. c. v. deal 30 Mm is 0.09 which is 90 g. It isn't kg in two CV value is 400. So we can guide us 400 into The bill that is four, which becomes cut P six into four. Mhm. So remaining hippies actually meaning is 26 into 100 minus four, which is 56 into 1962. So this remaining energy will increase the temperature of liquid. So no. Since energy balance energy, millions M c V delta T And see we did 30 what liquid is questioned. This will 2016 to 96. Now we will put the values here masses 300 g. So 0.32. See the value we have to calculate and Delta Delta T is 19-15 As opposed to 36 into 96. This is unit in jewels and other this unitary KGM kg and killing. So see we will be forced to 26 into 96 upon 0.32 four. And you know, it will be june four kg for kelvin. So severely will finally we this calculation which turns out to be see vehicles to mm 880 control RPG or killed. So this is our final answer.
Okay. So we've got our water at 20°C and we're going to move it into a freezer At at -20°C. So this temperature is eventually going to lower. That must mean it's losing heat. So Q. For our system is going to be negative after a few hours It's going to be very cold, right? It's going to be below 0°C. So our water is going to become ice so the state will be solid. So we said that Q is negative. All right, this is our heat of reaction is going to be negative so to start and then to finish plus some heat. So at the start our water has a higher entropy then at the finish and then finally, if we leave it in the freezer at negative 20 degrees Celsius for several hours, the final temperature is simply going to be negative 20 degrees Celsius.
Question Number 43 wants you to prepare a figure similar to a figure found on page three or 5 38 figure ah 15. 15. It shows positive. Delta H is a formation from elements to form no to and negative. Delta H is of formation when forming eso three from the elements. So we will start from the elements that form water in the gas phase and in the liquid phase. The elements that are used to form water are molecular, hydrogen and molecular oxygen, Molecular hydrogen and molecular oxygen both have delta h of formation values of zero, so they will be up here high in our figure. Then the delta H of formation of gaseous H 20 is negative 241 8 killed jewels, Permal and the formation of hydrogen. Our water liquid is negative to 85.8 kg goals per mole. So this means mawr energy is released in the formation of liquid water than in gaseous water. To determine the delta h of vaporization. It's simply going to be the difference in Delta H is of formation of liquid water and gaseous water, meaning we want to go from liquid water to gaseous water to solve for the Delta h of this process. Delta, referring to change, is always final state at this Delta H value, minus the initial state at this Delta H value. So we'll take the final state at negative 241.8 killed jewels for mole minus the initial state at negative to 85.8 kg per mole. And we get positive. 44 kill a Jules per mole and it should be positive because we need to add energy in to go from the liquid state to the gaseous state, meaning we need to go up the energy diagram as shown here.