A test tube becomes cool to the touch.
Explanation:
The signs for an endothermic reaction would most likely be that a test tube becomes cool to touch. An endothermic reaction is a reaction in which heat is absorbed from the environment.
- At the end of this heat change, the surrounding becomes colder.
- Most endothermic reactions are always shown by the test tube becoming colder.
- For exothermic reaction in which heat is given off to the surroundings, the tube should be hotter.
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Exothermic reactions brainly.com/question/10567109
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Answer:
20.53 g.
Explanation:
- Knowing that every 15.0 g of pure calcium fluoride contains 7.70 g of calcium.
<u>Using cross multiplication:</u>
15.0 g of pure calcium fluoride contains → 7.70 g of calcium.
40.0 g of pure calcium fluoride contains → ??? g of calcium.
<em>∴ The mass of Ca in 40.0 g of calcium fluoride</em> = (7.70 g)(40.0 g)/(15.0 g) = <em>20.53 g.</em>
Answer:
209.3 Joules require to raise the temperature from 10 °C to 15 °C.
Explanation:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m × c × ΔT
Given data:
mass of water = 10 g
initial temperature T1= 10 °C
final temperature T2= 15 °C
temperature change =ΔT= T2-T1 = 15°C - 10°C = 5 °C
Energy or joules added to increase the temperature Q = ?
Solution:
We know that specific heat of water is 4.186 J/g .°C
Q = m × c × ΔT
Q = 10 g × 4.186 J/g .°C × 5 °C
Q = 209.3 J
Answer:
- Heat energy is transferred from homes by conduction through the walls, floor, roof and windows. It is also transferred from homes by convection. For example, cold air can enter the house through gaps in doors and windows, and convection currents can transfer heat energy in the loft to the roof tiles.
- Convection is the heat transfer due to the movement of a fluid, such as a gas or liquid, and carries heat energy away from the source of heat. When a substance is heated, it causes its particles to vibrate more. The more vibration, the more space they will take up and the less dense they will become.
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Mitochondria because is the power house for cell,site for respiration or energy release.
