Answer:
A. 0.2395 w/w %
B. 2394ppm
Explanation:
A. To find concentrationin percent by mass of the solution we need to calculate mass of glycerol and mass of water. The formula is:
Mass glycerol / Total mass * 100
<em>Mass glycerol:</em>
The solution is 2.6x10⁻²moles / L. As there is 1L of solution there are 2.6x10⁻² moles of glycerol. In mass (Using molar mass glycerol: 92.09g/mol):
2.6x10⁻² moles of glycerol * (92.09g / mol) = 2.394g glycerol
<em>Mass of water:</em>
998.9mL and density = 0.9982g/mL:
998.9mL * (0.9982g/mL) = 997.1g of water.
That means percent by mass is:
% by mass: 2.394g / (997.1g + 2.394g) * 100 = 0.2395 w/w %
B. Parts per million are mg of glycerol per L of solution. As in 1L there are 2.394g. In mg:
2.394g * (1000mg / 1g) = 2394mg:
Parts per million: 2394mg / L = 2394ppm
Answer:
a) 37.04% b) 37.04% c) 9.63%
Explanation:
The theoretical percent recovery (Tr), is the total percentage of each compound in the sample. Depending on the technique used to recovery the compounds, the percent recovery will be less than the theoretical, because no technique is 100% efficient.
So, to calculate the theoretical, it will be the mass of the compound divided by the mass of the sample multiplied by 100%.
a) Tr = (250 mg)/(675 mg) * 100%
Tr = 37.04%
b) Tr = (250 mg)/(675 mg) * 100%
Tr = 37.04%
c) Tr = (65 mg)/(675 mg) * 100%
Tr = 9.63%
It will always produce a near-exact measurement
<span>A submerged object displaces a volume of liquid equal to the volume of the object. One milliliter (1 mL) of water has a volume of 1 cubic centimeter (1cm3).</span>
Explanation:
Thomson model compared the structure of the atom with a watermelon in which the red portion signifies the positive charge and the electrons which are negatively charged are embedded in this portion as seeds are embedded in the watermelon.
<u>The structure was not able to explain the stability of the atom and also the Rutherford experiment which is:</u>
Rutherford conducted an experiment in which he took a thin gold particle film on which he passes alpha- particles. He noticed that:
- Most of the alpha particles get through the film and can be detected by the detector.
- Around small portion of the alpha particle deflected at small angles.
- A very very few alpha particle (approximately 1 out of 1 million alpha particles) just retraced their path which means come back from the center.
He concluded that:
Most of space of atom is empty and in center of atom , there is solid mass which is cause of alpha particles to come back. He gave term nucleus to this solid mass.
