Answer: Option (b) is the correct answer.
Explanation:
Kinetic energy is defined as the energy obtained by the molecules of an object due to their motion.
Also, it is known that kinetic energy is directly proportional to temperature.
Mathematically, K.E = 
where, T = temperature
Whereas potential energy is defined as the energy obtained by an object due to its position.
Mathematically, P.E = mgh
where, m = mass
g = acceleration due to gravity
h = height
Therefore, in the given curve when temperature remains constant then kinetic energy of molecules will also remain.
Hence, we can conclude that the segment QR represents an increase in the potential energy, but no change in the kinetic energy.
By lowering temperature from liquid to solid, atoms lose some of their energy, when atoms slow down, they move close together and make the matter denser.
Answer and Explanation:
<em>A funnel is in the top of the buret and a beaker is positioned underneath the buret:</em> This is correct and is necessary to fill the buret, but the funnel and the beaker has to be removed before the titration starts. The calculation for moles of analyte does not affect.
<em>A solution is being poured from a bottle into the buret via the funnel:</em> Using a funnel helps to fill the burette but it must be removed to filling the buret at 0.0 mL. In this case, the calculation for moles of analyte do not affect.
<em>Adding titrant past the color change of the analyte solution</em>: In this case, an excess of titrant is added, thus the calculation for moles of anality will be higher than it should be.
<em>Recording the molarity of titrant as 0.1 M rather than its actual value of 0.01 M</em>: In this case, the titrant is considered more concentrated than it is hence, the calculation for moles of anality will be higher than it should be.
<em>Spilling some analyte out of the flask during the titration</em>: The excess of titrant spilled out of the flask higher up the volume of titrant measured. Therefore, the calculation for moles of anality will be higher than it should be.
<em>Starting the titration with air bubbles in the buret</em>: The air inside the burette occupies measured volume, thus the volume of titrant measured will be higher than the real volume spilled in the flask. Hence the calculation for moles of anality will be higher than it should be.
<em>Filling the buret above the 0.0 mL volume mark</em>: Some volume of titrant will be spilled inside the flask but will no be measured since the buret measures the titrant below the 0.0mL mark, thus the calculation for moles of anality will be lower than it should be.
<span>The mass of 1.73 moles CaH2 is 72.82 grams. The molar mass of CaH2 is 42.08 g/mol. This means that there are 42.09 grams in 1 mol. So, x grams will be in 1.73 mol of CaH2. Let's make a proportion: 42.09 g : 1 mol = x : 1.73 mol. x = 42.09 g * 1.73 mol : 1 mol. x = 72.82 g.</span>
