The question is incomplete, the complete question is;
An alcohol thermometer makes use of alcohol's changing _______ in order to measure temperature. As the temperature goes up, the alcohol contained in the thermometer increases in volume, filling more of the thermometer's tube.
A.
mass
B.
state
C.
chemical composition
D.
density
Answer:
D.
density
Explanation:
Every kind of thermometer makes use of a change in a particular physical property of a substance as a measure of temperature. It must be a property that changes with temperature.
Density of a substance changes with temperature. Even though the mass of alcohol in glass remains constant, but its volume increases or decreases with change in temperature leading to a change in volume and consequently a change in density of the alcohol in glass. This change is used as a measure of the change in temperature.
We have that energy=specific heat * change in temperature * mass. Thus, we have the final temperature (22) minus the initial temperature (55) to equal -33 as our change in temperature. Our specific heat is in J/g*C, so we're good with that because g stands for grams and the aluminium is measured in grams. As there are 10 grams of aluminum, we have
as our final temperature
An exothermic reaction would release energy and would therefore lose heat itself, while an endothermic reaction would absorb energy and gain heat. Therefore, losing heat would be an exothermic reaction
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Answer:
Number of moles = 0.05 mol
Explanation:
Given data:
Mass of Pb = 10.5 g
Number of moles of Pb = ?
Solution:
Formula:
Number of moles = mass/molar mass
Molar mass of Pb is 207.2 g/mol.
Now we will put the values in formula.
Number of moles = 10.5 g/207.2 g/mol
Number of moles = 0.05 mol
The molarity of a solution in which 55. 49 g of calcium chloride is dissolved in enough water to make 500. ml of solution is 1M.
<h3>What is molarity? </h3>
It is defined as number of moles of solute divided by volume of solution.
Given,
Mass of CaCl2 =55.49g
Molar mass of CaCl2 =40+35+35=110g
Mole= given mass/ molar mass
= 55.49/110=0.50mol.
Now, putting all values we get the molarity
Molarity =0.5×1000/500=1M
Thus, the molarity of given solution is 1M.
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Answer: 6 moles
Take a look at the balanced chemical equation for this synthesis reaction
N 2(g] + 3 H 2(g] → 2 NH 3(g]
Notice that you have a 1:3 mole ratio between nitrogen gas and hydrogen gas. This means that, regardless of how many moles of nitrogen gas you have, the reaction will always consume twice as many moles of hydrogen gas.
So, if you have 2 moles of nitrogen taking part in the reaction, you will need
2 moles N 2 ⋅ 3 moles H 2 /1 mole N 2 = 6 moles H 2
