Answer:
83.69 gm
Explanation:
molar weight of N2 = 28
Find the number of moles then multiply by this
1.8 x10^24/ (6.022x10^23) * 28 =83.69 gm
Answer: pure substances.
Explanation:
The given substances are:
All what surrounds us, which has mass and occupies spaces, is matter. There are two kind of matter: pure substances and mixtures.
Pure substances have a uniform and constant composition. On the other hand, mixtures are combinations of two or more pure substances in any arbitratry ratio.
Pure substances may be elements or compounds. The elements are the substances conmposed by one only kind of atom. In the list of substances given, Li and O₂ are elements: all the atoms in Li are lithium, and all the atoms in O₂ are oxygen atoms.
Compounds are the chemical combination of two or more different kind of atoms. In the given list H₂O₂ and NaCl are compounds. As you see, H₂O₂ contains atoms of hydrogen and oxygen, chemically bonded, in a fixed ratio (2 atoms of hydrogen by 2 atoms of oxygen). And NaCl has atoms of Na (sodium) and Cl (chlorine), chemicaly bonded, in a fixed ratio (1:1).
There are only 118 known elements and you can find them in any modern periodic table. Therer are virtually infinitely many compounds since many different combinations of the elements can be attained.
Elements and compounds have in common that they are classified as pure substances.
B. Heating up the reaction will increase the entropy of a reaction.
<h3>
What is entropy?</h3>
Entropy is the measure of the degree of disorderliness of a system.
Entropy is also the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work.
S = ΔH/T
where;
- S is entropy
- ΔH is energy input
- T is temperature
Entropy increases in reactions in which the total number of product molecules is greater than the total number of reactant molecules.
However, entropy increases as temperature increases. Thus, heating up the reaction will increase the entropy of a reaction.
Learn more about entropy here: brainly.com/question/6364271
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Answer: It will take 3 days for half of a 10 g sample to decay.
Explanation:
Half-life of sample of an isotope X = 3 days
Sample decayed = 
N=
, time = t
![\ln[5 g]=-0.231 day^{-1}\times t\ln[10]](https://tex.z-dn.net/?f=%5Cln%5B5%20g%5D%3D-0.231%20day%5E%7B-1%7D%5Ctimes%20t%5Cln%5B10%5D)
![\ln[\frac{5}{10}]=-0.231\times t](https://tex.z-dn.net/?f=%5Cln%5B%5Cfrac%7B5%7D%7B10%7D%5D%3D-0.231%5Ctimes%20t)
t = 3 days
It will take 3 days for half of a 10 g sample to decay.
