Answer: The empirical formula is
.
Explanation:
Mass of C = 1.71 g
Mass of H = 0.287 g
Step 1 : convert given masses into moles.
Moles of C = 
Moles of H = 
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C =
For H =
The ratio of C: H = 1: 2
Hence the empirical formula is
.
There are two naturally occurring isotopes of gallium: mass of Ga-69 isotope is 68.9256 amu and its percentage abundance is 60.11%, let the mass of other isotope that is Ga-71 be X, the percentage abundance can be calculated as:
%Ga-71=100-60.11=39.89%
Atomic mass of an element is calculated by taking sum of atomic masses of its isotopes multiplied by their percentage abundance.
Thus, in this case:
Atomic mass= m(Ga-69)×%(Ga-69)+X×%(Ga-71)
From the periodic table, atomic mass of Ga is 69.723 amu.
Putting the values,

Thus,

Rearranging,

Therefore, mass of Ga-71 isotope is 70.9246 amu.
Lets let our mass equal 3 on alletals and solve using d=m/v equation
Aluminum
V=3/2.70=1.11
Silver
V=3/10.5=.286
Rhenium
V=3/20.8=.144
Nickel
V=3/8.90=.337
This gives us the following list from largest to smallest Aluminum, Nickel, Silver, and Rhenium
For 1. 00 l of an aqueous buffer containing 60. 0 mmol of acetic acid (pa=4. 76) and 40. 0 mmol of acetate, the pH of this buffer is 4.58.
<h3>What is handerson Hasselbalch equation? </h3>
It is expressed as:
pH = pKa + log [A-]/[HA]
where,
[A-] is the molar concentration of conjugate base
[HA] is the molar concentration of weak acid
Given,
pKa = 4.76
<h3>Calculation of concentration:</h3>
C = n/V
= 60/1000
= 0.06M
C = 40/1000
= 0.04M
Now, substituting values in equation we get,
pH = 4.76 + log(0.04/0.06)
pH = 4.76 + (-0.176)
pH = 4.58
Thus by using Henderson Hasselbalch equation we find the value of pH of the buffer is 4.58.
learn more about pH :
brainly.com/question/9529394
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