Answer:
Your strategy here will be to use the molar mass of potassium bromide,
KBr
, as a conversion factor to help you find the mass of three moles of this compound.
So, a compound's molar mass essentially tells you the mass of one mole of said compound. Now, let's assume that you only have a periodic table to work with here.
Potassium bromide is an ionic compound that is made up of potassium cations,
K
+
, and bromide anions,
Br
−
. Essentially, one formula unit of potassium bromide contains a potassium atom and a bromine atom.
Use the periodic table to find the molar masses of these two elements. You will find
For K:
M
M
=
39.0963 g mol
−
1
For Br:
M
M
=
79.904 g mol
−
1
To get the molar mass of one formula unit of potassium bromide, add the molar masses of the two elements
M
M KBr
=
39.0963 g mol
−
1
+
79.904 g mol
−
1
≈
119 g mol
−
So, if one mole of potassium bromide has a mas of
119 g
m it follows that three moles will have a mass of
3
moles KBr
⋅
molar mass of KBr
119 g
1
mole KBr
=
357 g
You should round this off to one sig fig, since that is how many sig figs you have for the number of moles of potassium bromide, but I'll leave it rounded to two sig figs
mass of 3 moles of KBr
=
∣
∣
∣
∣
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
a
a
360 g
a
a
∣
∣
−−−−−−−−−
Explanation:
<em>a</em><em>n</em><em>s</em><em>w</em><em>e</em><em>r</em><em>:</em><em> </em><em>3</em><em>6</em><em>0</em><em> </em><em>g</em><em> </em>
<u>larger is the value of </u>
<u> the higher will the solubility of solid in water.</u>
What is called compound?
- In chemistry, a compound is a substance made up of two or more different chemical elements combined in a fixed ratio.
- When the elements come together, they react with each other and form chemical bonds that are difficult to break.
- These bonds form as a result of sharing or exchanging electrons between atoms.
The equation for the dissociation of a solid MX in water is given below
MX(s) ⇄ Mⁿ⁺(aq) + Xⁿ⁻ (aq)
Assume s be the solubility of MX in pure water, then the equilibrium concentrations of ions are
[ Mⁿ⁺] = s
[ Xⁿ⁻ ] = s
The expression for the solubility product constant (
) is as follows
= [ Mⁿ⁺] [ Xⁿ⁻ ]
= s²
That is, larger is the value of
the higher will the solubility of solid in water.
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The ph of the best buffer is 4.74
The given acetic acid is a weak acid
The equation of the pH of the buffer
pH = pKa + log ( conjugate base / weak acid ).
For best buffer the concentration of the weak acid and its conjugate base is equal.
pH = pKa + log 1
pH = pKa + 0
pH = pKa
given Ka = 1.8 × 10⁻⁵
pKa = - log ka
pH = -log ( 1.8 × 10⁻⁵ )
pH = 4. 74
Hence the pH of the best buffer is 4.74
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Answer: A
Explanation:
Extreme weather events follow normal climate patterns.
Answer:
d. K<1 E∘cell is negative
Explanation:
Since E⁰ = negative , ΔG = -nFE⁰ = -nF -ve = +ve.
Also, ΔG = -RTlnK
K = exp(-RTΔG)
Since ΔG = +ve, -RTΔG = -ve
K = 1/exp(RTΔG) < 1.
So our answer is E⁰ cell is negative and K < 1