Answer is: <span>it comes at the right time.
Some of the chemistry discoveries that come in right time (with enough informations, knowledge and right technology to use that discovery) are: </span>Periodic Table of the Elements, discovery of electron, proton, neutron, radioactivity, pasteurization, t<span>he Haber-Bosch process.</span>
To get the PH we are going to use Henderson - Hasselblach equation:
PH = Pka + ㏒ [A/AH]
when the molar mass of Na2HPO4 = 142 g/mol
and A is the conjugate base HPO4-- ions so,
∴[A] = 26g / 142 g/mol
= 0.183 M
and when the molar mass of KH2PO4 = 136 g/mol
and AH is the weak acid H2PO4- ions so,
∴[AH] = 13 g / 136 g/mol
= 0.096 M
and when we have the Pka value of H3PO4 = 7.21
so, by substitution:
∴ PH = 7.21 + ㏒ (0.183 / 0.096)
= 7.49
Let's look at the molar weight of the answers:
NO is 30 g/mol
NO2 is 46
N2O is 44
N2O4 is 124
<span>We have the grams of the product, so we need the moles in order to calculate the molar weight. We us PV=nRT for this, assuming standard temperature and pressure. </span>
You were given the liters (.120L)
Std pressure is 1 atmosphere
You're looking for n, the number of moles
<span>Temp is 293.15 kelvin, thats standard </span>
And r is the gas constant in liters-atm per mol kelvin
(.120 liters)(1atm)=n(293.15K)(.08206)
Solving for n is .0049883835 mol
<span>.23g divided by .0049883 mol is about 46g/mol. You're answer is B I think, NO2
I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
</span>
<span>The coorrect answer is option A. The pressure of the gas can cause the ideal gas constant R, to take dfferent values. Because all the other three factors namely, Temperature (T), Volume(V) and the number of moles (n) can change the pressure of a gas. So, I f we change the pressure of the gas alone, we can change its gas constant R value.</span>
It’s b make contact with the heat source