Answer:
1.2 ( two significant digits)
Explanation:
5.4 - 4.21 answer should only have the the number of significant digits as the number in the equation with the least number of significant digits... in this case 5.4 is only two significant digits....so the answer should only have two significant digits
5.4 - 4.21 = 1.19 round to two digits = 1.2
Answer:
water is H2O having different structure than alcohol R-OH which means they have different properties too.
Explanation:
In water one oxygen atom is covalently bound with two hydrogen atoms while alcohol is an organic compound having Oh group attached to the carbon chain.
Other than liquid water can occur in solid form that is ice and in gaseous form that is vapors too while alcohol only present in liquid form.
heat of evaporation of alcohol is lower than water means water need more heat to evaporate than alcohol that is why we can say alcohol having more cooling effect than water.
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 0.139M 0M 0M
Δ[] -x +x +x
[]f 0.139-x x x
Then, using the concentration equation, you get
4.5x10^-4 = [H+][NO2-]/[HNO2]
4.5x10^-4 = x*x / .139 - x
However, because the Ka value for nitrous acid is lower than 10^-3, we can assume the amount it dissociates is negligable,
assume 0.139-x ≈ 0.139
4.5x10^-4 = x^2/0.139
Then, we solve for x by first multiplying both sides by 0.139 and then taking the square root of both sides.
We get the final concentrations of [H+] and [NO2-] to be x, which equals 0.007M.
Then to find percent dissociation, you do final concentration/initial concentration.
0.007M/0.139M = .0503 or
≈5.03% dissociation.
