Answer:
6.82 kg
Explanation:
Given that the amount of water is 15L and we know that the density of water is ≈ 1kg/L. The mass of water is given by mass = volume x density, i.e,
mass = 15 x 1 = 15 kg. Also the specific heat capacity of water is 4.186 KJ/kg.
The sublimation enthalpy of dry ice is 571 KJ/kg.
Now, the amount of heat lost by water is entirely used up for the sublimation (conversion from soild to gas) of dry ice. And the heat (Q) lost by water is given as : Q = mCΔT, where m is the mass of water, C the specific heat capacity of water and ΔT the change in temperature.
Here, Q = 15 x 4.186 x (90 - 28) = 3892.98 KJ.
This amount of heat is taken up by the dry ice for its sublimation. Also the energy taken by dry ice (Q') for its sublimation is given by: Q' = m'L', where m' is the mass of dry ice, L' is the latent heat of sublimation (i.e, the amount of heat required per kg of a substance to sublime) of dry ice amd L' = 571 KJ/kg.
Now, Q' =m'L' = heat lost by water = 3892.98KJ.
And, m'L' = m' x 571 KJ/kg = 3892.98 KJ. (Dividing with 571)
Therefore, m' = 6.82 kg.
The mole fraction of solute in a 3.87 m aqueous solution is 0.0697
<h3>
calculation</h3>
molality = moles of the solute/Kg of the solvent
3.87 m dissolve in 1 Kg of water= 1000g
find the moles of water= mass/molar mass
that is 1000 g/ 18 g/mol= 55.56 moles
mole of solute = 3.87 moles
mole fraction is = moles of solute/moles of solvent
that is 3.87/ 55.56 = 0.0697
Answer:19. He says that he’s been really tired since several weeks ago. 20. A friend of us is going to pick us up at the airport. 21. I’ve worked like a waiter in the past, but I wouldn’t want to do it again. 22
Explanation:
Gallium metal is heated in oxygen gas, it melts and forms solid gallium(III) oxide.
Ga + O₂⇒ Ga O₂
Balance the atoms with simple - whole coefficients.
4 Ga + 3 O₂ 2 Ga₂O₃.
Specify the states of matter.
4 Ga(s) + 3 O₂ (g) ⇒ 2 Ga₂O₃.(s)
Therefore, balanced equation is----- 4 Ga(s) + 3 O₂ (g) ⇒ 2 Ga₂O₃.(s)
What is the balanced formula equation?
A balanced equation is an equation for a chemical reaction in which the number of atoms for each element in the reaction and the total charge is the same for both the reactants and the products. In other words, the mass and the charge are balanced on both sides of the reaction.
Why are equations balanced?
A balanced equation obeys the Law of Conservation of Mass. This is an important guiding principal in science. Finally, a balanced equation lets up predict the amount of reactants needed and the amount of products formed.
Learn more about balanced equation:
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Answer:
<h3>1)</h3>
Structure One:
Structure Two:
Structure Three:
Structure Number Two would likely be the most stable structure.
<h3>2)</h3>
- All five C atoms: 0
- All six H atoms to C: 0
- N atom: +1.
The N atom is the one that is "likely" to be attracted to an anion. See explanation.
Explanation:
When calculating the formal charge for an atom, the assumption is that electrons in a chemical bond are shared equally between the two bonding atoms. The formula for the formal charge of an atom can be written as:
.
For example, for the N atom in structure one of the first question,
- N is in IUPAC group 15. There are 15 - 10 = 5 valence electrons on N.
- This N atom is connected to only 1 chemical bond.
- There are three pairs, or 6 electrons that aren't in a chemical bond.
The formal charge of this N atom will be 
.
Apply this rule to the other atoms. Note that a double bond counts as two bonds while a triple bond counts as three.
<h3>1)</h3>
Structure One:
Structure Two:
Structure Three:
In general, the formal charge on all atoms in a molecule or an ion shall be as close to zero as possible. That rules out Structure number one.
Additionally, if there is a negative charge on one of the atoms, that atom shall preferably be the most electronegative one in the entire molecule. O is more electronegative than N. Structure two will likely be favored over structure three.
<h3>2)</h3>
Similarly,
- All five C atoms: 0
- All six H atoms to C: 0
- N atom: +1.
Assuming that electrons in a chemical bond are shared equally (which is likely not the case,) the nitrogen atom in this molecule will carry a positive charge. By that assumption, it would attract an anion.
Note that in reality this assumption seldom holds. In this ion, the N-H bond is highly polarized such that the partial positive charge is mostly located on the H atom bonded to the N atom. This example shows how the formal charge assumption might give misleading information. However, for the sake of this particular problem, the N atom is the one that is "likely" to be attracted to an anion.
