Answer:
D. Grams liquid x mol/g x delta Hfreezing
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to reason that the stoichiometry used to calculate energy released when a mass of liquid freezes, involves the grams of the liquid, the molar mass of the liquid, as given in all the group choices, and the enthalpy of freezing because that is the process whereby a liquid goes solid.
In such a way, we infer that the correct factor would be D. Grams liquid x mol/g x delta Hfreezing which sometimes is the negative of the enthalpy of fusion as they are contrary processes.
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Answer:
Hygroscopic
Explanation:
An hygroscopic substance is one that absorbs moisture from the atmosphere and becomes wet. Their ability to remove water from air is less than that of deliquescent substances. Most of the solid hygroscopic substances forms pasty substances and not solutions like the deliquescent compounds.
Examples are sodium trioxonitrate(v), copper(ii) oxide e.t.c
Efflorescence compounds gives off their water of crystallization to the atmosphere.
Answer:
Elements can be described by various properties, and identified by their boiling and melting points. For example, gold melts at
Elements can be described by various properties, and identified by their boiling and melting points. For example, gold melts at 1,064ºC and boils at 2,856ºC. Does boiling point depend on the mass present?
A. No; chemical properties stay the same regardless of mass.
B. No; physical properties stay the same regardless of mass.
C. Yes; physical properties can change when mass increases or decreases.
D. No; qualitative properties like boiling point stay the same regardless of mass.
Explanation:
First a balanced reaction equation must be established:
→
Now if mass of aluminum = 145 g
the moles of aluminum = (MASS) ÷ (MOLAR MASS) = 145 g ÷ 30 g/mol
= 4.83 mols
Now the mole ratio of Al : O₂ based on the equation is 4 : 3
[
4Al +
3 O₂ → 2 Al₂O₃]
∴ if moles of Al = 4.83 moles
then moles of O₂ = (4.83 mol ÷ 4) × 3
=
3.63 mol (to 2 sig. fig.)
Thus it can be concluded that
3.63 moles of oxygen is needed to react completely with 145 g of aluminum.
<u>Answer</u>:-
Name of element = Lead
Symbol ♾ of Lead = Pb
Atomic no. = 82
Atomic mass = 207.2 amu
No. of protons = 82
No. of electrons = 82
Yes, lead(Pb) is a metallic element and certainly it has 6 electron shells which means 6 energy level.
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