Answer:
15.89grams
Explanation:
The mass of a substance can be calculated from it's mole value by using the formula:
mole = mass/molar mass
According to this question, there are 0.250 moles of copper. Hence, the mass of copper can be calculated as follows:
Molar mass of Cu = 63.55g/mol
0.250 = mass/63.55
mass = 0.250 × 63.55
mass = 15.8875
Mass of Cu in 0.250mol is 15.89grams.
Answer:
+4
Explanation:
In PbO2, oxygen exhibits an oxidation number of -2 (since it's not a peroxide or superoxide):
Let the oxidation number of Pb be x. Then, for the compound to be neutral, the oxidation numbers of all atoms should add up to zero.
⇒ x + (−2) + (−2) = 0
x = +4
So the oxidation no. of Pb is +4.
I hope this helps.
First, we need to get the value of Ka:
when Ka = Kw / Kb
we have Kb = 1.8 x 10^-5
and Kw = 3.99 x 10^-16 so, by substitution:
Ka = (3.99 x 10^-16) / (1.8 x 10^-5) = 2.2 x 10^-11
by using the ICE table :
NH4+ + H2O →NH3 + H+
intial 0.013 0 0
change -X +X +X
Equ (0.013-X) X X
when Ka = [NH3][H+] / [NH4+]
by substitution:
2.2 x 10^-11 = X^2 / (0.013 - X) by solving this equation for X
∴X = 5.35 x 10^-7
∴[H+] = X = 5.35 x 10^-7
∴PH = - ㏒[H+]
= -㏒(5.35 x 10^-7)
= 6.27
Answer with Explanation:
Different versions of a gene are called alleles. Alleles are described as either dominant or recessive depending on their associated traits. Since human cells carry two copies of each chromosome they have two versions of each gene.
