Answer:
Density = 8.92 g/cm³
Explanation:
Density shows the relation of the mass and volume of a determined object. We have this deffinition:
Density = mass / volume
First of all, we calcualte the volume of the block of copper metal, with the data given:
8.4 cm . 5.5 cm . 4.6 cm = 212.52 cm³
Now we replace at the density formula:
Density = 1896 g /212.52 cm³ = 8.92 g/cm³
For one mole of hydrogen, H, the atomic mass is 1 g per mole. Hydrogen contains 1 proton and zero neuton. A neutral atom of hydrigen also contains 1 electron.
<u>Ans: 650 J = 155 calories</u>
<u>Given:</u>
Energy in joules = 650 J
<u>To determine:</u>
The energy in calories
<u>Explanation:</u>
1 joule = 0.2388 calories
Therefore, 650 joules = 0.2388 calories * 650 J/1 J = 155 calories
Ok first, we have to create a balanced equation for the dissolution of nitrous acid.
HNO2 <-> H(+) + NO2(-)
Next, create an ICE table
HNO2 <--> H+ NO2-
[]i 0.230M 0M 0M
Δ[] -x +x +x
[]f 0.230-x x x
Then, using the concentration equation, you get
4.5x10^-4 = [H+][NO2-]/[HNO2]
4.5x10^-4 = x*x / .230 - x
However, because the Ka value for nitrous acid is lower than 10^-3, we can assume the amount it dissociates is negligable,
assume 0.230-x ≈ 0.230
4.5x10^-4 = x^2/0.230
Then, we solve for x by first multiplying both sides by 0.230 and then taking the square root of both sides.
We get the final concentrations of [H+] and [NO2-] to be x, which equals 0.01M.
Then to find percent dissociation, you do final concentration/initial concentration.
0.01M/0.230M = .0434 or
≈4.34% dissociation.
