Answer:
Dissolving sugar in water, burning paper, and melting gold are all chemical changes
Explanation:
The action cannot be reversed, or undone. Therefore it is a chemical change.
Boiling water is a physical change.
Answer:
5.41 ×10⁻²²
Explanation:
We were told right from the question that both the Zinc ions and the Zinc oxide adopts a face-centered cubic arrangement.
Then, the number of ZnO molecule in one unit cell = 4
The standard molar mass of ZnO = 81.38g
Avogadro's constant = 6.023 × 10²³ mole
∴
The mass of one unit cell of zinc oxide can be calculated as:
= 
= 5.40461564×10⁻²²
≅ 5.41 ×10⁻²²
∴ The mass of one unit cell of zinc oxide = 5.41 ×10⁻²²
I believe the correct answer is C, but I'm 100% on this. Hope this helped though!
-TTL
Answer: The elements that have the lowest electronegativity are the VIII A elements or noble gases. These elements have a theoretical electronegativity of zero. These elements are stable in their electron configuration there is not force moving the noble gases to gain any electrons.
Explanation:
Toulene = 35.6 g
Benzene = 125 g = 0.125 kg
Molecular weight of Toluene C6H5CH3 = 92.1g/mol
Moles of toulene = 35.6 g / 92.1 g/mol = 0.3865 mol
Now the molarity of the toulene in the given solution = 0.3865 / 0.125 = 3.092 m
Molarity of C6H5CH3 = 3.092 m
