Blue light waves have more energy than red light waves. Which of theses situations most likely produces a photoelectric effect?
You may assume that the same metal is used in each situation. Check all that apply. -shining dim red light on a strip of metal
-shining bright red light on a strip of metal
-shining dim blue light on a strip of metal
-shining bright blue light on a strip of metal
Hot material near Earth's surface is more dense and sinks, and when it cools, it becomes less dense and rises.
Explanation:
Convection is a process by which less dense material rises and more dense material sinks near Earth's surface. Water, air, rocks and other materials expands when temperature rises and they become less dense. When the water is heated it becomes vapors and carries away thermal energy from the water.
a. Jonathan would like to develop a hypothesis regarding the role of parental expression of affection in reducing toxic stress in early childhood.
Explanation:
A descriptive method is commonly known as a research method for describing the properties or features of the research area being investigated. Descriptive research is usually conducted by studying the trends of the phenomenon without changing the value of any variable in the system. Thus, the correct answer is option a.
<span>The solution of ethanol will have the greatest increase in boiling point.
The formula for boiling point elevation is:
ΔTb = Kb · bB
where
ΔTb = boiling point elevation
Kb = ebullioscopic constant for the solvent bB = molarity of the solution
Since in the solute is nonionic, we don't have to worry about the molecules of the solute breaking up into multiple ions, thereby increasing the effective molarity of the solution. So which ever solvent has the highest ebullioscopic constant, will have the greatest increase in boiling point. This constant can be calculated by the equation:
Kb = RTb^2M/ΔHv
where
R = Ideal gas constant
Tb = boiling point of pure solvent
M = Molar mass of solvent
ΔHv = heat of vaporization per mole of solvent
For our purposes, we can ignore the idea gas constant, and instead look at only the boiling point, molar mass, and heat of vaporization. Then calculate Tb^2M/ΔHv So let's do so:
(Note: Not bothering to be precise in molar mass. If the end result is close, then I'll bother. Otherwise, just using nice round numbers).
Water
Boiling point: 373.15 K
Molar mass: 18 g/mol
heat of vaporization: 40660 J/mol
Tb^2M/ΔHv: 61.64
Ethanol
Boiling point: 351.52 K
Molar mass: 46 g/mol
heat of vaporization: 38600 J/mol
Tb^2M/ΔHv: 147.26
The value of Tb^2M/ΔHv is significantly greater for ethanol than it is for water (by more than 2 to 1), so it will have the greatest increase in boiling point.</span>
