Express the following temperatures in the indicated units:
0 º C = 0 + 273 = 273 K
25 º C = 25 + 273 = 298 K
473 K = 473 - 273 = 200 ºC
-5 ºC = -5 + 273 = 268 K
253 K = 253 - 273 = -20 ºC
0ºC = 32 + 9/5 · 0 = 32ºF
25ºC = 32 + 9/5 · 25 = 77ºF
302ºF = (302 -32) · 5/9 = 150ºC
-5 ºC = 32 + 9/5 · (-5) = 32 - 5 · 9/5 = 23 ºF
-22ºF = (-22 - 32) · 5/9 = -30ºC
Read the paragraph below and complete the missing words.
1. minus - 273 ºC
0 K
2. B
ΔT = Q / (m · ce)
Since c e is in the denominator, the larger c e is, the smaller ΔT is. They are inversely proportional.
3. B
ΔT = Q / (m · ce)
Since m is in the denominator, the larger m is, the smaller ΔT is. They are inversely proportional.
4. If we put two bodies at different temperatures in contact, heat will be transferred from the hot to the cold until both reach the same temperature, at which point it is said that they have reached thermal equilibrium.
5. Heat can be measured in Joules or calories.
6. During a change of state the temperature remains constant, because the heat is used to overcome the forces of attraction between particles, instead of increasing their speed and kinetic energy.
Explain the following graph in your notebook. Justify at the molecular level what happens inside a body that explains the dependence of thermal energy on mass and temperature.
Audio:
Thermal energy is defined as the internal energy contained in a body or system, due to the vibration and movement of its particles.
The more mass the body has, the more particles it will have. And the higher its temperature, the faster they will move. Therefore, the greater the mass and the higher the temperature, the greater the thermal energy.
A 100 g lead bullet is at 90 ºC . How much heat must be extracted from it to cool it to 30 ºC? ce(Pb) = 130 J/(kg K)
Audio:
Q = m · ce · ΔT
ΔT =Tfinal - Tinitial = 30 - 90 = -60 ºC
Q = 0,1 · 130 · (-60) = - 780 J
Audio:
Read and complete :
Audio:
The process of heat transfer that involves the transfer of matter and thermal energy is called convection. When there is a transfer of thermal energy, but not of matter, we speak of conduction. And in cases where heat can be transmitted without the need for a material medium, it is called transfer by radiation.
Soup in a pot is heated by convection. The handles of the pot, if metal, are heated by conduction.
The sun's thermal energy reaches us by radiation.
Read and choose the correct word:
Convection currents are the result of temperature differences in a fluid. When part of the fluid is heated, it expands and becomes less dense, causing it to rise. At the same time, the cooler, denser fluid tends to sink. These upward and downward movements create currents that are known as convection currents.
One of the best-known examples of convection currents is found in the Earth's atmosphere, where they play a key role in shaping weather patterns and transporting heat around the planet.
The air closest to the Earth's surface absorbs heat that the Earth emits through greenhouse gases. This warm air rises from the Earth's surface and cooler air sinks, creating circulation patterns that influence climate and weather. These currents are also responsible for the formation of storms and clouds. Understanding these interactions is critical to improving weather predictions and studying climate change.
Read the paragraph below and fill in the missing words.
On an oven we see an inscription that says 2000 W/230 V. What does this mean ? How much electricity will this oven have consumed after 45 minutes of operation?
Audio:
This means that the oven consumes 2000 J of energy every second it is plugged into the 220 V mains voltage. The energy consumed in 45 minutes is: 5400 kJ = 1.5 kW h
E (J) = P (W) · t (s) = 2000 · 45 · 60 = 5400 · 103 J = 5400 kJ
E (kW·h) = P (kW) · t (h) = 2 · 0,75 = 1.5 kW·h
Read the paragraph below and fill in the blanks with the value of the appropriate magnitude, symbol or unit.
Audio:
a) P = I · V = 4,35 · 230 = 1000 W
b) R = V/I = 230 / 4,35 = 52.9 Ω
c) E = P · t = 1000 W · 60 s = 60.000 J
Audio:
A room is illuminated by three 80 W bulbs. How much does it cost to have them on for 6 h if the price per kW·h is 0.2 €? Write the result to two decimal places after the decimal point.
Audio:
Energy 1 light bulb: E = 0,08 · 6 = 0,48 kW·h
3 light bulbs: E = 3 · 0,48 = 1,44 kW·h
Cost = 1,44 · 0,2 = 0,29 €
Audio:
The efficiency of an electric stove is 60%. Calculate the thermal energy it produces if it consumes an energy of 3000 kJ.
Audio:
Efficiencia = Useful energy · 100 / consumed energy
Useful energy = efficiency · consumed energy / 100 = 60 · 3000 / 100 = 1800 kJ
Audio:
Some of the household appliances that consume the most electricity in a home are the refrigerator, the television, the washing machine and the oven. What influences consumption is their power and the number of hours they are usually plugged in. For example, a refrigerator does not have as much power as an oven or a washing machine, but since it is always plugged in, it consumes more energy.
Imagine that you have a 600 W class E refrigerator at home. It breaks down and when you go to replace it with another one of the same power, you wonder whether it is worth replacing it with a class A one, which costs €2000, or whether it would be better to buy a class G one, for €1500.
Calculate how much money you save per year with a class A unit compared to a class G unit . We consider the class E unit to have average consumption and we calculate the increases and decreases in energy consumption of the others based on the energy consumed by the E unit. We consider that the price of the kW h is €0.2.
Energy labeling of household appliances, Alberto Martínez, Desenchufados, CC BY 4.0
The amount consumed by E per year will be: E (kW h) = 0.6 kW 24 h/day 365 days/year = 5256 kW h
Class A consumes less than 55% of what Class E consumes:
Energy = E = 0.55 · 5256 = 2891 kW·h
The G class consumes 125% of what the E consumes:
E = 1.25 · 5256 = 6570 kw·h
Annual operating cost class A = 2891 · 0.2 = 578 €
Annual cost of class G operation = 6570 · 0.2 = 1314 €
Annual savings: €736
Within a year you will have recovered the difference you paid in the price.
Read the paragraph below and complete the missing words.
kg CO2 class A: 2891 kW h/year · 0.19 kg CO2/kW h = 549.3 kg CO2/year
kg CO2 class G: 6570 kW·h/year · 0.19 kg CO2/kW·h = 1248.3 kg CO2 /year
Difference = 1258.3 - 549.3 = 699 kg CO2/year
Red Eléctrica is the company responsible for the operation of the electricity system in our country, transporting electricity from the generation plants to the distribution points. In their website that we can see the demand for electricity in Spain in real time.
Go to: demanda.ree.es
And clic "seleccionar sistema"/"nacional"
There you can see a graph representing the electricity demand throughout the day.
At the top right side there is a pie chart showing the distribution of the percentage of energy produced by the different types of power plants in the country. By clicking on any of those sectors you can see at the bottom right side the amount of energy produced throughout the day from that source and its CO2 emissions.
Move around the site to familiarize yourself with it.
Select the day before the current day below the x-axis of the main graph to have a full day's data and answer the questions:
1. What is the main energy source that is supplying Spain electricity today?
2. What is the renewable energy that is being primarily used to produce electricity between 11 in the morning and 4 in the afternoon?
3. What is the non-renewable energy that is used during the rest of the day to compensate the electricity requirements?
4. What are the hours of the day with the highest electricity demand in Spain?
5. Which is the only energy source that has a constant generation rate and use?
6. What percentage of our electric energy come from renewable sources?
1. Usually wind power, but it depends on the environmental conditions
2. Usually solar power, but it depends on the environmental conditions
3. Thermal energy (ciclo combinado)
4. 6:00-10:00
18:00-22:00
5. Nuclear
6. Today (december 2024): 50 %
Find out how much CO2 you emit when you shower:
1. Calculate the water flow rate of your shower tap by measuring the time it takes to fill a 1 L container. Flow rate = Volume/time
2. Measure the time it takes you to shower
3. Calculate the L of water you spent by multiplying the flow rate you obtained in (1) by the time you obtained in (2)
4. Convert them to kg taking into account that dwater = 1 kg/L
5. Calculate the energy you spent, with the equation: Q = m · ce · ΔT
m = result of section (4)
ce water = 4180 J/(kg·ºC)
Tf = T hot water = 40 ºC
Ti = T cold water = 20 ºC
6. Convert to kW·h (1 kW·h = 3.6 · 106 J )
7. Calculate the kg of CO2 that you emit knowing that the generation of 1 kWh of electricity in Spain emits around 0.19 kg of CO2
Adivina la fuente de energía que esconde cada una de las siguientes tarjetas. Haz clic en la tarjeta para comprobar si tu respuesta es correcta.
Número de tarjetas: 11
Aciertos: 0
Errores: 0
Puntuación: 0
Energy sources, Canva, Licencia de Canva
Relate each electrical power stations to the energy transformations taking place in it:
Número de tarjetas: 7
Aciertos: 0
Errores: 0
Puntuación: 0
Relaciona cada tarjeta con su pareja.
Número de tarjetas: 5
Aciertos: 0
Errores: 0
Puntuación: 0
Look at the maps and complete the text using the information they provide. They are interactive maps where you can see the data for each country by placing the cursor over it on the map or selecting it from the tab that says "world" (situated above the map, on the right). You can also see the data in table or graph format, by selecting it from the menu above the graph, on the left (table/map/chart).
In the bottom bar you can scroll between the years 1985 and 2023 to see data for any year within that range.
https://ourworldindata.org/grapher/share-electricity-renewables?tab=map
https://ourworldindata.org/grapher/share-electricity-hydro?tab=map
https://ourworldindata.org/grapher/share-electricity-wind?tab=map
https://ourworldindata.org/grapher/share-electricity-solar?tab=map
In pairs, try to solve this problem and answer the question using the following data.
You can ask for hints, if you need them, to help you through the problem. To be given the hints in order, click on "Show a hint". The solution to this exercise can be found in Activity 21.
Audio data:
Audio question of the problem:
Audio tracks:
Número de preguntas: 1
Aciertos: 0
Errores: 0
Puntuación: 0.00
Score: 0
Hits: 0
Errors: 0
Solution:
Electrical emissions = 25,500 kW·h · 0.19 kg CO2/kW·h = 4845 kg CO2
Emissions gasoline = 8250 L · 10 kW·h/L · 0.19 kg CO2/kW·h = 15675 kg CO2
Difference = 15675 - 4845 = 10830 kg CO2
Look at the letters, identify and fill in the missing words.
Número de preguntas: 10
Aciertos: 0
Errores: 0
Puntuación: 0
3
Score: 0
Hits: 0
Errors: 0
Licensed under the Creative Commons Attribution Share Alike License 4.0
.jpeg)
