Answer:
42.9%
Explanation:
the total number of coins is 15+14+6 = 35
so to find the % of pennies, divide the number of pennies by the total number of coins and times it all by 100
15/35 x 100 = 42.9%
Answer:

Explanation:
Hello,
In this case, for first order reactions, we can use the following integrated rate law:
![ln(\frac{[A]}{[A]_0} )=kt](https://tex.z-dn.net/?f=ln%28%5Cfrac%7B%5BA%5D%7D%7B%5BA%5D_0%7D%20%29%3Dkt)
Thus, we compute the time as shown below:
![t=-\frac{ln(\frac{[A]}{[A]_0} )}{k}=- \frac{ln(\frac{0.220M}{0.690M} )}{0.55s^{-1}} \\\\t=-\frac{-1.14}{0.550s^{-1}}\\ \\t=2.08s](https://tex.z-dn.net/?f=t%3D-%5Cfrac%7Bln%28%5Cfrac%7B%5BA%5D%7D%7B%5BA%5D_0%7D%20%29%7D%7Bk%7D%3D-%20%5Cfrac%7Bln%28%5Cfrac%7B0.220M%7D%7B0.690M%7D%20%29%7D%7B0.55s%5E%7B-1%7D%7D%20%5C%5C%5C%5Ct%3D-%5Cfrac%7B-1.14%7D%7B0.550s%5E%7B-1%7D%7D%5C%5C%20%5C%5Ct%3D2.08s)
Best regards.
Answer:
The answer is
<h2>2.7 g/mL</h2>
Explanation:
The density of a substance can be found by using the formula

From the question
mass of aluminum = 40.5 g
volume = 15 mL
Substitute the values into the above formula and solve for the density
We have

We have the final answer as
<h3>2.7 g/mL</h3>
Hope this helps you
The temperature : 332.75 K
<h3>Further explanation</h3>
Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters / mol.
volume of gas = 790 cm³ = 0.79 L
mol of gas at STP :

Use ideal gas :

P=726 mmHg=0.955 atm
V= 1000 cm³ = 1 L
