are all the question multiple choice?
Answer:
The value is 
Explanation:
Generally the reaction between oxygen and magnesium is
Generally from the law of mass conservation in a chemical reaction we have that
Here 
is the mass of magnesium
is the mass of oxygen
is the mass of magnesium oxide
So
=> 
=>
They are different by a phase shift of pi/2
7. D. 668 joules
8. B. 3 grams
<h3>Further explanation</h3>
Given
2 grams of water
6768 joules of energy
Required
Energy
Mass of water
Solution
The heat to change the phase can be formulated :
Q = m.Lf (melting/freezing)
Q = m.Lv (vaporization/condensation)
Lf=latent heat of fusion
Lv=latent heat of vaporization
7. phase change (ice to water)⇒Heat of fusion water=334 J/g
Q = 2 g x 334 J/g
Q = 668 J
8. phase change(water to vapor)⇒heat of vaporization water=2260 J/g
6768 J = m x 2260 J/g
m = 3 g
Answer:
The molarity of 2.0 liters of an aqueous solution that contains 0.50 mol of potassium iodide is 0.25M.HOW TO CALCULATE MOLARITY:The molarity of a solution can be calculated by dividing the number of moles by its volume. That is;Molarity = no. of moles ÷ volumeAccording to this question, 2.0 liters of an aqueous solution that contains 0.50 mol of potassium iodide. The molarity is calculated as follows:Molarity = 0.50mol ÷ 2LMolarity = 0.25MTherefore, the molarity of 2.0 liters of an aqueous solution that contains 0.50 mol of potassium iodide is 0.25M.Learn more about molarity at: brainly.com/question/2817451
Explanation:
Mark me brainliest please!!! I spent a lot of time on this!!
