Answer
2.0 x 10²³ molecules.
Explanation
Given:
The number of moles of theobromide measured out = 0.333 moles.
MM of theobromide = 180.8 g/mol
What to find:
The number of molecules of theobromide the student measured.
To go from moles to molecules, multiply the number of moles by Avogadro's number.
The Avogadro's number = 6.02 x 10²³
1 mole of theobromide contains 6.02 x 10²³ molecules.
So, 0.333 moles of theobromide measured out will have (0.333 x 6.02 x 10²³) = 2.0 x 10²³ molecules.
Answer:
(A) 15.0 °C
Explanation:
The water in beaker A gains heat because its initial temperature (10 °C) is less than the initial temperature of the water in beaker B (20 °C) which loses heat.
Let T3 be the final temperature
Heat gained by beaker A = heat loss by beaker B
mc(T3 - T1) = mc(T2 - T3)
The mass and specific heat of water in both beakers are the same. Therefore, (T3 - T1) = (T2 - T3)
T1 is initial temperature of beaker A = 10 °C
T2 is initial temperature of beaker B = 20 °C
T3 - 10 = 20 - T3
T3 + T3 = 20 + 10
2T3 = 30
T3 = 30/2 = 15 °C
3:00m cu of the current in electrical engineering and electrical toques
Answer: 4 molL-1
Explanation:
Detailed solution is shown in the image attached. The number of moles of NaCl is first obtained. Since the molarity must be in units of molL-1, the volume is divided by 1000 and the formula stated in the solution is applied and the answer is given to one significant figure.
I’m not sure if there was important information in the question before this one, but the answer based on the info I have is B.
The density of water is 1kg/L. Since the density of the block is less, it will float.
