The IUPAC says that elements have to be named after one of five things: a scientist, a place, a mineral or substance, a descriptor of the element, or a mythological reference. Of the new elements, three are named after places and one is named after a person No-one has yet named an element after themselves but many elements are named in tribute to important scientists
(you can cut some stuff out)
Faralho me dá ponti pdbvvv
.....i don't understand the question sorry
Ka for weak acids is ---> Ka= (X)²/ (initial- X)
initial= 0.0400 M
to find X, you can find the H concentration using pH
[H+]= 10^-pH
[H+]= 10^-1.80= 0.016 which is X
ka = (0.016)²/ (0.0400 - 0.016) = 0.011
The given question is incomplete. The complete question is as follows.
From the following formula, calculate the quantities required for each of the following ingredients to make 5 lb. (avoir) of hydrophilic ointment. All values to be in g, do not include units in your submitted answer; use no more than 3 decimal places. Convert using 1 lb = 454 g. Note: all values done by mass, including the water, so this is not a q.s situation (volume is irrelevant).
Methylparaben 0.25 g
Propylparaben 0.15 g
Sodium Lauryl Sulfate 10 g
Propylene Glycol 120 g
Stearyl Alcohol 240 g
White Petrolatum 250 g
Purified Water, to make 1000 g
Explanation:
For the given quantities, the sum is 620.4 g. Now, amount of purified water (to make 1000 g of ointment) is as follows.
1000 g - 620.4 g
= 379.6 g
Now, to make 5 lb we will calculate the quantities as follows.
Formula weight = 1000 g
Therefore, desired quantity is as follows.
5 lb = 5 x 454 g
= 2270 g
Hence, this means the factor is calculated as follows.
= 2.27
Now, we will calculate the quantity of each ingredient using factor 2.27 as follows.
-
Methylparaben = 0.25 g x 2.27 = 0.5675 g
-
Propylparaben = 0.15 g x 2.27 = 0.3405 g
-
Sodium Lauryl Sulfate = 10 g x 2.27 = 22.7 g
-
Propylene Glycol = 120 g x 2.27 = 272.4 g
-
Stearyl Alcohol = 240 g x 2.27 = 544.8 g
-
White Petrolatum = 250 g x 2.27 = 567.5 g
-
Purified Water = 379.6 g x 2.27 = 861.692 g