Answer:
Here's what I get
Explanation:
A. Initial observation
Gary's shell had slime and an odour.
B. Independent variable
The independent variable is the one that the experimenter changes.
There are two independent variables: the rubbing with seaweed and the drinking of Dr. Kelp.
C. The dependent variable
The dependent variable is the amount of slime and odour.
D. The conclusion
Sponge Bob can conclude that rubbing the shell with seaweed and drinking Dr. Kelp removes the slime and odour.
However, this was a poorly designed experiment. He doesn't know if it is the seaweed or the Dr. Kelp that gives the result or if he must use both together. He should change only one independent variable at a time.
Chemical equations are to be balanced to be able to follow the law of conservation of mass where it says that mass cannot be created or destroyed. Reactions should be that the mass of the reactants is equal to the mass of the products.
We assume that we have Ka= 4.2x10^-13 (missing in the question)
and when we have this equation:
H2PO4 (-) → H+ + HPO4-
and form the Ka equation we can get [H+]:
Ka= [H+] [HPO4-] / [H2PO4] and we have Ka= 4.2x10^-13 & [H2PO4-] = 0.55m
by substitution:
4.2x10^-13 = (z)(z)/ 0.55
z^2 = 2.31x 10^-13
z= 4.81x10^-7
∴[H+] = 4.81x10^-7
when PH equation is:
PH= -㏒[H+]
= -㏒(4.81x10^-7) = 6.32
Answer:
Option B, Because of the reversible nature of crystallizing and dissolving
Explanation:
Solution containing the maximum amount of solute that can be dissolved in the given solvent at the particular temperature is called saturated solution.
Reversible reaction is the reaction which can go in reverse and forward direction both on varying reaction condition.
In the saturated NaCl solution, on lowering temperature, The the dissolved NaCl molecules may crystallize. Likewise on increasing temperature, the crystallized crystals may dissolved. As the reaction moves in both the direction, therefore its considered to be equilibrium system.
Therefore, amog given, option B is correct.
Because of the reversible nature of crystallizing and dissolving
