As he began to teach inorganic chemistry, Mendeleev could not find a textbook that met his needs. Since he had already published a textbook on organic chemistry in 1861 that had been awarded the prestigious Demidov Prize, he set out to write another one. The result was Osnovy khimii (1868–71; The Principles of Chemistry), which became a classic, running through many editions and many translations. When Mendeleev began to compose the chapter on the halogen elements (chlorine and its analogs) at the end of the first volume, he compared the properties of this group of elements to those of the group of alkali metals such as sodium. Within these two groups of dissimilar elements, he discovered similarities in the progression of atomic weights, and he wondered if other groups of elements exhibited similar properties. After studying the alkaline earths, Mendeleev established that the order of atomic weights could be used not only to arrange the elements within each group but also to arrange the groups themselves. Thus, in his effort to make sense of the extensive knowledge that already existed of the chemical and physical properties of the chemical elements and their compounds, Mendeleev discovered the periodic law.
Answer: All of the statements are true.
Explanation:
(a) Considering the system mentioned in the equation:-
The sum of total moles in the flask will always be equal to 1 which leads to confirmation of this statement as for 60 secs= 0.16 mol A and 0.84 mol B
(b) 0<t< 20s, mole A got reduced from 1 mole to 0.54 moles while at 40s to 60s A got decreased from 0.30 moles to 0.16 moles.
0 to 20s is 0.46 (1 - 0.54 = 0.46)mol whereas,
40 to 60s is 0.14 (0.30-.16 = 0.14) mol
(0.46 > 0.14) mol leading this statement to be true as well.
(c) Average rate from t1 = 40 to t2 = 60 s is given by:
which is true as well
Answer:
Option (A). The mass of the rusted nail equals the mass of iron and the oxygen from the air it reacted with to form the rust.
Answer:
Dust and smoke.
Explanation:
Dust and smoke are two different particles present in the air. Dust and smoke are different from one another due to their origin. Smoke formed from burning of materials while dust refers to the soil particles lifted by the wind due to their light weight. Dust and smoke are similar to each other due to their small in size, infinite number means uncountable and light weight.
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
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