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4 years ago

8

brina thinks dissolvung more salt in water cause the mixture freezing temperature to chang which is the best type of sciectific

investigation for brena to use to study this

1 answer:

ddd [48]4 years ago

7 0

put some water out with less salt and then some more water out with more salt and look at the differences with the freezing.

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Draw the major resonance contributors for the enamine shown. do not draw resonance and curved arrows. include formal charges and

Makovka662 [10]

<em>Answer:</em>

There are two major resonance contributors for the en-amine. One contributor have no formal charges, only have one lone pair at N while the other one has positive and negative formal charges.

<em>Explanation:</em>

An en-amine is formed by the condensation reactions of aldehydes or ketone with secondary amine.

The contributor<em> </em>I have no formal charges. It has only one lone pair at Nitrogen atom.

The contributor II has +1 formal charges at N, and -1 formal charges at α Carbon.

Please see attachment. The resonance contributor are given.

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3 years ago

3) (Solid magnesium carbonate mixed in a solution of dilute hydrochloric acid. Assume the

Virty [35]

<u>Answer:</u> The mass of magnesium carbonate that will be dissolved in the reaction is 6.99 g.

<u>Explanation:</u>

We are given:

Amount of heat released = 1950 J = 1.950 kJ (Conversion factor: 1 kJ = 1000 J)

The chemical equation for the reaction of magnesium carbonate and hydrochloric acid follows:

$MgCO_3+2HCl\rightarrow MgCl_2+H_2O+CO_2;\Delta H_{rxn}=-23.4kJ$

By Stoichiometry of the reaction:

If 23.4 kJ of heat is released, then 1 mole of magnesium carbonate is dissolved

So, when 1.950 kJ of heat is released, then = $\frac{1mol}{23.4kJ}\times 1.950kJ=0.083mol$ of magnesium carbonate is dissolved

To calculate the mass of the substance by given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of magnesium carbonate = 0.083 moles

Molar mass of magnesium carbonate = 84.3 g/mol

Putting values in above equation, we get:

$0.083mol=\frac{\text{Mass of magnesium carbonate}}{84.3g/mol}\\\\\text{Mass of magnesium carbonate}=0.083mol\times 84.3g/mol=6.99g$

Hence, the mass of magnesium carbonate that will be dissolved in the reaction is 6.99 g.

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3 years ago

What causes the convection cell to turn downward

Leviafan [203]

Gravity when the mantle cools it becomes heavier and therfore sinks

4 0

4 years ago

The standard free energy of formation, ΔG∘f, of a substance is the free energy change for the formation of one mole of the subst

OLEGan [10]

Answer:

B. 2 Na(s) + O₂(g) → Na₂O₂(s); ΔG∘f=−451.0 kJ/mol

D. 2 SO(g) + O₂(g) → 2 SO₂(g); ΔG°f=−600.4 kJ/mol

Explanation:

The spontaneity of a reaction is given by the value of the standard Gibbs free energy of the reaction (ΔG°rxn). The more negative is the ΔG°rxn, the more spontaneous is a reaction.

The ΔG°rxn can be calculated using the following expression:

ΔG°rxn = ∑np × ΔG°f(products) − ∑nr × ΔG°f(reactants)

By definition, the standard Gibbs free energy of formation of simple substances in their most stable state is zero. That is why, in the reaction of formation of a compound ΔG°rxn = ΔG°f(product).

<em>Based on the standard free energies of formation, which of the following reactions represent a feasible way to synthesize the product? </em>

<em> A. N₂(g) + H₂(g) → N₂H₄(g); ΔG°f=159.3 kJ/mol. </em>

<em> </em>Not feasible. ΔG°rxn = ΔG°f(product) > 0.

<em>B. 2 Na(s) + O₂(g) → Na₂O₂(s); ΔG°f=−451.0 kJ/mol</em>

Feasible. ΔG°rxn = ΔG°f(product) < 0.

<em>C. 2 C(s) + 2 H₂(g) → C₂H₄(g); ΔG°f=68.20 kJ/mol</em>

Not feasible. ΔG°rxn = ΔG°f(product) > 0.

<em>D. 2 SO(g) + O₂(g) → 2 SO₂(g); ΔG°f=−600.4 kJ/mol</em>

Feasible. ΔG°rxn = ΔG°f(product) < 0.

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4 years ago

Josie created a Venn Diagram to determine the differences and similarities between weather and climate. PLSSS HELP I HAVE 15 MIN

DENIUS [597]

Answer:

Climate is long time intervals and weather is short time intervals

Explanation:

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3 years ago