Answer:
Ka= 2.3 x 10^-11
Explanation:
so Ka x Kb = Kw where Kw=10^-14 at 25 degrees Celsius
plugging in Kb and Kw, we have
Ka x 4.4 x 10^-4 = 10^-14
solving for Ka,
Ka= (10^-14)/(4.4 x 10^-4)
Ka= 2.3 x 10^-11
The atomic mass of Europium is 152 amu
Work:
151(0.4803) = 72.52 amu
153(0.5197) = 79.5 amu
72.5 + 79.5 = 152 amu
Freezing
Explanation:
This change in state when surface of a lake changes to hard ice is known as freezing.
- When a solid is heated, it melts and changes to a liquid. On further heating, it changes to vapor and the randomness increases.
- When a liquid is cooled below its freezing point, it changes to a solid such as ice for water.
- The phase change is known as freezing.
Learn more:
Phase change brainly.com/question/1875234
#learnwithBrainly
For the first question, salt is soluble while sand is insoluble or not dissolvable in water. The salt should have vanished or melted, but the sand stayed noticeable or visible, making a dark brown solution probably with some sand particles caught on the walls of the container when the boiling water was put in to the mixture of salt and sand. The solubility of a chemical can be disturbed by temperature, and in the case of salt in water, the hot temperature of the boiling water enhanced the salt's capability to melt in it.
For the second question, the melted or dissolved salt should have easily made its way through the filter paper and into the second container, while the undissolved and muddy sand particles is caught on the filter paper. The size of the pores of the filter paper didn’t change. On the contrary, the size of the salt became smaller because it has been dissolved which is also the reason why it was able to go through the filter paper, while the size of the sand may have doubled or even tripled which made it harder to pass through.
The answer is rounded off to 0.0278 mol C6H12O6
