Answer:
C, because it will then begin to become a solid but it will still be water but frozen so more like ice then.
The concentration of the drug stock solution is 1.5*10^-9 M i.e. 1.5 * 10^-9 moles of the drug per Liter of the solution
Therefore, the number of moles present in 1 ml i.e. 1*10^-3 L of the solution would be = 1 *10^-3 L * 1.5 * 10^-9 moles/1 L = 1.5 * 10^-12 moles
1 mole of the drug will contain 6.023*10^23 drug molecules
Therefore, 1.5*10^-12 moles of the drug will correspond to :
1.5 * 10^-12 moles * 6.023*10^23 molecules/1 mole = 9.035 * 10^11 molecules
The number of cancer cells = 2.0 * 10^5
Hence the ratio = drug molecules/cancer cells
= 9.035 *10^11/2.0 *10^5
= 4.5 * 10^6
Answer:
Explanation:
The model written correctly is:
This is a mathematical question, instead of a chemistry question, and you should use calculus to find the nitrogen level that gives the best yield, since this is an optimization problem.
The best yield is the maximum yield, and the maximum, provided that it exists, is found using the first derivative and making it equal to zero: Y' = 0
To find Y' you must use the quotient rule.
Now make Y' = 0
- The denominator is never equal to zero, because it is always positive and greater than 9.
- Make the numerator equal to zero:
9k - kN² = 0
- Since k is a positve constant, it is not equal to zero, and the other factor, 9 - N², must be equal to zero:
9 - N² = 0 ⇒ (3 - N) (3 + N) = 0
⇒ 3 - N = 0 or 3 + N = 0 ⇒ N = 3 or N = -3.
Since N is nitrogen level, it cannot be negative and the only valid answer is N = 3.
You can prove that it is a maximum (instead of a minimum) finding the second derivative or testing some points around 3 (e.g. 2.5 and 3.5).
Answer:
The main advantage would be that with the pouring temperature being much higher, there is very little chance that the metal will solidify in the mould while busy pouring. This will allow for moulds that are quite intricate to still be fully filled. The drawbacks, though, include an increased chance defects forming which relates to shrinkage (cold shots, shrinkage pores, etc). Another drawback includes entrained air being present, due to the viscosity of the metal being low because of the high pouring temperature.