Answer:
Physical properties: how soft a blanket it, how hard bread is, what color leaves are, what bleach smells like.
Chemical change: burning wood, rotting food, digestion, rusting of a nail.
Physical change: mixing salt and sugar, tearing a piece of paper, melting ice, chopping wood.
Explanation:
Physical properties are properties that are measurable.
Chemical change is when substances combine (fire and wood make burning wood) to make another substance. They aren't reversible. If you were to melt ice, you could refreeze it, you can't unburn wood.
Physical change is something that alters the form of the substance but not the chemical composition.
Hope this helps!
The ph of a saturated solution of Ca(OH)2 is 12.35
CALCULATION:
For the reaction
Ca(OH)2 → Ca2+ + 2OH-
we will use the Ksp expression to solve for the concentration [OH-] and then use the acid base concepts to get the pH:
Ksp = [Ca2+][OH-]^2
The listed Ksp value is 5.5 x 10^-6. Substituting this to the Ksp expression, we have
Ksp = 5.5 x 10^-6 = (s) (2s)^2 = 4s^3
s3 = 5.5x10^-6 / 4
Taking the cube root, we now have
s = cube root of (5.5x10^-6 / 4)s
= 0.01112
We know that the value of [OH-] is actually equal to 2s:
[OH-] = 2s = 2 * 0.01112 = 0.02224 M
We can now calculate for pOH:
pOH = - log [OH-]
= -log(0.02224)
= 1.65
Therefore, the pH is
pH = 14 - pOH
= 14 - 1.65
= 12.35
Answer:
= 25 ppm
Explanation:
- PPM also refers to parts per million, it represents a low concentration of a solution. It represents 0.001 gram or a milligram in a 1000 mL, which equivalent to 1 mg per liter.
Given; a sample size of 2000 g contained 0.050 g DDT
It means, 2000 mL sample contained 50 mg DDT
Therefore in ppm we get;
= 50 mg/ 2 L
= 25 mg/L
<u>= 25 ppm</u>
Answer:
Gold: 1.1 x 10²² atoms/cm³
Silver: 4.8 x 10²² atoms/cm³
Explanation:
100 g of the alloy will have 29 g of Au and 71 g of Ag.
19.32 g Au ____ 1 cm³
29 g Au ______ x
x = 1.5 cm³
10.49 g Ag ____ 1 cm³
71 g Ag _______ y
y = 6.8 cm³
The total volume of 100g of the alloy is x+y = 8.3 cm³.
Gold:
196.97 g Au____ 6.022 x 10²³ atoms Au
29 g Au _______ w
w = 8.9 x 10²² atoms Au
8.9 x 10²² atoms Au ____ 8.3 cm³
A ____ 1 cm³
A = 1.1 x 10²² atoms Au
Silver:
107.87 g Ag____ 6.022 x 10²³ atoms Ag
71 g Ag _______ w
w = 4.0 x 10²³ atoms Ag
4.0 x 10²³ atoms Ag ____ 8.3 cm³
B ____ 1 cm³
B = 4.8 x 10²² atoms Ag
Answer:
The cation Fe3+ is formed when a. an atom of iron loses two electrons.
Explanation:
