Because the birds that fly overseas carry different flu viruses every year.
Answer:
Mole fraction H₂O → 0.72
Mole fraction C₂H₅OH → 0.28
Explanation:
By the mass of the two elements in the solution, we determine the moles of each:
25 g . 1 mol/ 18g = 1.39 moles of water (solute)
25 g . 1 mol / 46 g = 0.543 moles of ethanol (solvent)
Mole fraction solute = Moles of solute / Total moles
Mole fraction solvent = Moles of solvent / Total moles
Total moles = Moles of solute + Moles of solvent
1.39 moles of solute + 0.543 moles of solvent = 1.933 moles → Total moles
Mole fraction H₂O = 1.39 / 1.933 → 0.72
Mole fraction C₂H₅OH= 0.543 / 1.933 → 0.28
Remember that sum of mole fractions = 1
Hydrogen gas is produced when dilute hydrochloric acid is added to a reactive metal.
Balanced molecular equation of sodim metal with hydrochloric acid:
2Na(s) + 2HCl(aq) → 2NaCl(aq) + H₂(g).
Ionic equation: 2Na(s) + 2H⁺(aq) + 2Cl⁻(aq) → 2Na⁺ + 2Cl⁻(aq) + H₂(g).
Net ionic equation: 2Na(s) + 2H⁺(aq) → 2Na⁺(aq) + H₂(g).
Sodium is oxidized from oxidation number 0 (Na) to oxidation number +1, hydrogen is reduced from oxidation number +1 to oxidation number 0 (hydrogen gas H₂).
Another example:
Balanced chemical equation: Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g)
Word equation: zinc + hydrochloric acid → zinc chloride + hydrogen gas
More about hydrogen gas:brainly.com/question/24433860
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Carbon atomic number ⇒ 6
Carbon mass number ⇒ 12.
Carbon atomic number - Carbon mass number = number of neutrons.
12 - 6 = 6 neutrons.
Proton charge ⇒ +1
The total charge of the nucleus of a carbon atom ⇒⇒⇒ +6.
So the naswer is (3) +6
