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Viktor [21]
3 years ago
10

Please help! I’m on my last attempt

Chemistry
1 answer:
deff fn [24]3 years ago
6 0
First line: The atomic number is the whole number on the periodic table so atomic number 35 means the element is bromine. Thus the element symbol is Br. The atomic number is also the number of protons in the isotope so the number of protons is 35. The mass number is the sum of protons and neutrons in the isotope so the mass number is 35+46 or 81. The mass number gives you the top left number on the nuclear symbol (it will look the same as the one below it except the 79 is an 81). Lastly, the number of electrons is equal to the number of protons in a neutral atom so 35 electrons.
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What will the pressure of H+ ions in a solution cause
suter [353]

ACIDIC BEHAVIOR OF SOLUTION

6 0
3 years ago
Commercial cold packs often contain solid NH4NO3 and a pouch of water. The temperature of the pack drops as the NH4NO3 dissolves
Yanka [14]

Answer: b. \Delta H_{soln} is positive and \Delta S_{soln} is positive.

Explanation:-

As the temperature of the pack drops, the energy has been absorbed from the pack for dissolution of NH_4NO_3 in water. Thus as the energy has been absorbed in the reaction, the reaction is endothermic and the change in enthalpy i.e. \Delta H_{soln} is positive.

The entropy is the measure of degree of randomness. The entropy increases when the randomness increases and the entropy decreases when the randomness decreases. When a substance dissolves in water, it dissociate into ions and hence the randomness increases thus the change in entropy i.e. \Delta S_{soln}  is positive.

NH_4NO_3\rightarrow NH_4^++NO_3^-

7 0
3 years ago
What is the overall cell potential for this redox reaction? Ca2+ + 2Li = Ca + 2Li+ Ca2+ + 2e- = Ca -2.87 V Li = Li+ + e- -3.05 V
Jet001 [13]

The redox reaction is

Ca^{+2}  + 2Li(s)  = Ca(s) + 2Li^{+}

Here

Calcium undergoes reduction, and acts as cathode

Lithium undergoes oxidation and acts as anode

The reduction potential of calcium is -2.87 V

The reduction potential of lithium is - -3.05 V

We know that

Ecell = Ecathode - Eanode

Ecell = -2.87 - (-3.05)  = 0.18 V


4 0
3 years ago
A 0.175 M solution of an enantiomerically pure chiral compound D has an observed rotation of +0.27° in a 1-dm sample
-BARSIC- [3]

Answer:

The specific rotation of D is 11.60° mL/g dm

Explanation:

Given that:

The path length (l) =  1 dm

Observed rotation (∝) = + 0.27°

Molarity = 0.175 M

Molar mass = 133.0 g/mol

Concentration in (g/mL) = 0.175 mol/L × 133.0 g/mol

Concentration in (g/mL) = 23.275 g/L

Since 1 L = 1000 mL

Concentration in (g/mL) = 0.023275 g/mL

The specific rotation [∝] = ∝/(1×c)

= 0.27°/( 1  dm ×  0.023275 g/mL )

= 11.60° mL/g dm

Thus, the specific rotation of D is 11.60° mL/g dm

3 0
3 years ago
In the oxidation reduction reaction 2FeCl2 + Cl2 = 2FeCl3 what substance is reduced? What substance is oxidized?
marishachu [46]

Answer:

Iron is oxidized while chlorine is reduced.

Explanation:

The oxidation reduction reactions are called redox reaction. These reactions are take place by gaining or losing the electrons and oxidation state of elements are changed.

Oxidation:

Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.

Reduction:

Reduction involve the gain of electron and oxidation number is decreased.

Consider the following reaction:

2FeCl₂  + Cl₂  →  2FeCl₃

in this reaction the oxidation state of iron is increased from +2 to +3. That's why iron get oxidized and it is reducing agent because it reduced the chlorine. The chlorine is reduced from -2 to -3 and it is oxidizing agent because it oxidized the iron.

2Fe⁺²Cl₂⁻²

2Fe⁺³Cl₃⁻³

The iron atom gives it three electrons to three atoms of chlorine and gain positive charge while chlorine atom accept the electron and form anion.

4 0
3 years ago
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