Endothermic and Exothermic
You hold a piece of ice in your hand. The ice feels cold and it starts melting. Is this an example of an endothermic or exothermic process?
endothermic
A balloon is taken outside on a cold winter day and it deflates. What gas law is demonstrated?
Charles' law
The temperature of a gas is increased. What happens to the kinetic energy of the gas particles?
increases
What phase occurs when a solid turns into a gas?
sublimation
Name an element that is a metalloid.
B, Si, Ge, As, Sb, Te, Po
A reaction is exothermic. What would you expect the value of enthalpy to be?
negative
What are the 4 properties of gases that are measured for the gas laws?
pressure, volume, temperature, moles
Why can gases be easily compressed?
mostly empty space
During a phase change, what happens to the temperature of the substance?
stays the same
synthesis
increase
A person squeezes a balloon with both of their hands. What happens to the pressure of the gas inside the balloon?
increases
What causes pressure?
collision of gas particles with their container
Would freezing be classified as an endothermic or exothermic phase change?
exothermic
What sublevel comes after 5s?
4d
potassium chloride dissolves in water that is at 25oC. The temperature of the solution after the KCl dissolves is 2oC. Is this process endothermic or exothermic?
endothermic
What gas laws are combined together for the combined gas law?
Boyle's, Charles', Gay-Lussac's
What property of gases determines the speed that the particles move at if they are both at the same temperature?
molar mass
What phase change requires energy to break the forces holding the molecules together causing the molecules to separate?
melting, vaporization, sublimation
Why is potassium metal more reactive than sodium metal?
Sodium reacts with chlorine to produce sodium chloride and lots of heat. How would the energy of the sodium chloride compare to the sodium and chlorine?
It would be lower.
A 23 L container holds 3.45 g of hydrogen gas at a pressure of 1.89 atm. The temperature of the gas needs to be determined using which gas law?
ideal
Two gases, one with a small molar mass and one with a larger mass, are at the same temperature. Which one would exert the greatest pressure?
the lighter gas
What happens to the energy and particle motion of a substance that is vaporizing?
energy increases, particles speed up
Which element caused a water crisis in Flint, Michigan in 2014?
Pb