Answer:
A) yes
B) The average mass of 12 pennies should be expressed as
( 3.131 + 3.129 + -------- X12 ) g / 12
where X12 = is the mass of the 12th penny
Explanation:
A) I think the the Bureau of Mint changed the way it made pennies because from the experiment and observation carried out on 15 different pennies it can be seen that they had different weights and this difference is associated with the period/time of production of the different pennies,
B ) The average mass of any object should be expressed in the si unit of mass and not having ($) sign attached to the value instead it should be expressed in grams or kilograms (s.i unit of mass )
The average mass of 12 pennies should be expressed as
( 3.131 + 3.129 + -------- X12 ) g / 12
where X12 = is the mass of the 12th penny
The mass of Zr deposited in the process is 41.4 g.
<h3>What is electrolytic cell?</h3>
An electrolytic cell is a chemical cell which produces electrical energy by non-spontaneous chemical processes.
From the question;
Zr^4+(aq) + 4e ------> Zr(s)
We know that;
91 g of Zr is deposited by 4(96500) C
xg of Zr is deposited by (7.92 × 6.16 × 60 × 60) C
xg = 91 g × (7.92 × 6.16 × 60 × 60) C/4(96500) C
x g = 41.4 g
Learn more about electrolysis: brainly.com/question/12054569
Molar mass:
O2 = 31.99 g/mol
C8H18 = 144.22 g/mol
<span>2 C8H18(g) + 25 O2(g) = 16 CO2(g) + 18 H2O(g)
2 x 144.22 g --------------- 25 x 31.99 g
10.0 g ----------------------?? ( mass of O2)
10.0 x 25 x 31.99 / 2 x 144.22 =
7997.5 / 288.44 => 27.72 g of O2
hope this helps!
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