Freeze & Melt
Water freezes at this point (in degrees celsius).
What is 0°C?
Temperature is a measure of this.
What is average kinetic energy?
When calculating the change in termperature, the formula you will need to use is this.
What is △T = Tf - Tᵢ ?
When energy is transferrred, the calories gained will be equal to the number of calories lost. This is called the Law of ___________.
What is the Law of Conservation of Energy?
Dissolving and melting are both this type of change.
What is physical?
True or False: All substances freeze at 0°C.
False. Butter melts around room temperature. While steel freezes at 2500°C.
When the temperature of the room goes up, the liquid inside the thermometer will __________, changing the reading on the thermometer.
What is expand?
When calculating calories, you will need to use this formula.
What is calories = mass * △T ?
When transferring energy, the speed of the particles will do this.
What is increase?
Sugar dissolves easily in water. Sugar can be said to have a high ____________.
What is solubility?
Freezing is the opposite of this phenemnon. The only difference is whether the energy is being transferred to a substance or away from the substance.
What is melting?
When the temperature of the room changes, the number of particles of the liquid inside the thermometer will change in this way.
What is no change?
When you mix a sample of hot water with a sample of cold water, the calories lost from the hot should be ________, when compared with the calories gained in the cold.
What is the same number, but opposites (one negative, one positive. e.g. -500 and 500 calories)?
A substance will melt when the kinetic energy of the substance does this.
What is increases enough for particles to begin to move past one another?
When a solute dissolves in a solvent, the sugar's state of matter will become ___________.
What is nothing? When dissolved, the sugar will have no state of its own. But it will behave like a liquid if the solvent is a liquid.
Melting is a change in the state of matter caused by this.
What is increasing energy?
When the volume of the liquid inside a thermometer expands, the pressure of the liquid will change in this way.
What is increases?
Calculate the number of calories lost from a sample that is 250 mL when the sample started at 25°C and finsihed at 30°C
1,250 calories
(30 - 25 = 5°C.
250g * 5°C = 1,250 calories)
When energy is transferred, the size of the particles will do this.
What is stay the same size?
What is energy transfer / heat?
When something melts, the particles of that substance are moving faster, which does this to the volume.
What is expands?
What is transfer energy to the thermometer until equilibrium is reached?
One way to check your work is to see if the change in temperature has this type of number when the sample lost heat, and this type of number when the sample gained heat.
What is negative change in temperature for losing heat, and positive change in temperature for gaining heat?
What is equilibrium?
Sugar dissolves in water because the water molecules do this. (You may draw a diagram.)
What is physically break sugar apart and surround individual particles with many particles of water.