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2 years ago

In the reaction Zn(s) + NO3- → (aq) Zn2+ (aq) + NH4+ (aq) which element is reduced?

Chemistry

1 answer:

anyanavicka [17]2 years ago

4 0

Answer: N (the Nitrogen)

Explanation:

Reduction refers to a decrease in oxidation number/state due to the gaining of electrons. As such the species that is being reduced will show a decrease in oxidation state.

Based on the redox rules,

Zn(s) has oxidation number of 0 [rule 1: the oxidation number of an element in its free (uncombined) state is zero]

Zn²⁺ has oxidation number of +2 [rule 2: The oxidation number of a monatomic (one-atom) ion is the same as the charge on the ion]

Now, since Nitrogen is enbedded in a polyatomic ion in both cases, you have to do a bit a calculation to obtain the oxidation state.

For NO₃⁻ : N + (-2 × 3) = -1

N - 6 = -1

N = 5

[Rule 3: The sum of all oxidation numbers in a polyatomic (many-atom) ion is equal to the charge on the ion; Rule 6: The oxidation state of hydrogen in a compound is usually +1]

For NH₄⁺ :

N + (4 x 1) = 1

N + 4 = 1

N = -3

[Rule 3: The sum of all oxidation numbers in a polyatomic (many-atom) ion is equal to the charge on the ion; Rule 5: The oxidation number of oxygen in a compound is usually –2]

Therefore, Zn moves from oxidation state of 0 to +2 (oxidation), while N moves from +5 to -3 (reduction).

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Which compound would be expected to show intense IR absorption at 2710 and 1705 cm-1? (Ph = phenyl group)

Serhud [2]

Answer:

B. PhCHO

Explanation:

Every organic group shows a characteristic IR absorption at certain wavelength . With the help of these absorption spectra we can identify the group present on organic molecules .

The wave number of 2710 cm⁻¹ is absorbed by aldehyde bond stretching .

The wave number of 1705 cm⁻¹ is shown by conjugated aldehyde . So the most likely compound among given compounds is PhCHO .

7 0

2 years ago

HA and HB are two strong monobasic acids. 25.0cm3 of 6.0mol/dm3 HA is mixed with 45.0cm3 of 3.0mol/dm3 HB.

Lostsunrise [7]

Answer:

The H+ (aq) concentration of the resulting solution is 4.1 mol/dm³

(Option C)

Explanation:

Given;

concentration of HA, $C_A$ = 6.0mol/dm³

volume of HA, $V_A$ = 25.0cm³, = 0.025dm³

Concentration of HB, $C_B$ = 3.0mol/dm³

volume of HB, $V_B$ = 45.0cm³ = 0.045dm³

To determine the H+ (aq) concentration in mol/dm³ in the resulting solution, we apply concentration formula;

$C_iVi = C_fV_f$

where;

$C_i$ is initial concentration

$V_i$ is initial volume

$C_f$ is final concentration of the solution

$V_f$ is final volume of the solution

$C_iV_i = C_fV_f\\\\Based \ on \ this\ question, we \ can \ apply\ the \ formula\ as;\\\\C_A_iV_A_i + C_B_iV_B_i = C_fV_f\\\\C_A_iV_A_i + C_B_iV_B_i = C_f(V_A_i\ +V_B_i)\\\\6*0.025 \ + 3*0.045 = C_f(0.025 + 0.045)\\\\0.285 = C_f(0.07)\\\\C_f = \frac{0.285}{0.07} = 4.07 = 4.1 \ mol/dm^3$

Therefore, the H+ (aq) concentration of the resulting solution is 4.1 mol/dm³

7 0

2 years ago

How do models help scientists predict the polarity of molecules?

yuradex [85]

Answer:There are three main properties of chemical bonds that must be considered—namely, their strength, length, and polarity. The polarity of a bond is the distribution of electrical charge over the atoms joined by the bond. Specifically, it is found that, while bonds between identical atoms (as in H2) are electrically uniform in the sense that both hydrogen atoms are electrically neutral, bonds between atoms of different elements are electrically inequivalent. In hydrogen chloride, for example, the hydrogen atom is slightly positively charged whereas the chlorine atom is slightly negatively charged. The slight electrical charges on dissimilar atoms are called partial charges, and the presence of partial charges signifies the occurrence of a polar bond.

Explanation:

8 0

2 years ago

Read 2 more answers

If you have 2.41 × 1024 atoms of copper, how many moles of copper do you have? If you have 2.41 atoms of copper, how many moles

Bogdan [553]

Answer:

4.00 moles

Explanation:

Avogadro´s number is 6.022 x 10²³ molecules, atoms, particles, etc.

Here we are talking of atoms of copper, so 1 mol of copper is equal to 6.022 x 10²³ atoms, and we only need to setup the proportion to find the number of mol in 2.41 x 10²⁴ atoms. ( Think of it like a dozen, avogadro´s is 6.022 x 10²³ )

( 1 mol copper/ 6.022 x 10²³ atoms of copper ) x 2.41 x 10²⁴ atoms

= 4.00 moles

4 0

2 years ago

Martin is conducting an experiment. His first test gives him a yield of 5.2 grams. His second test gives him a yield of 1.3 gram

Anvisha [2.4K]

I Think The answer is c I hope it helps My friend Message Me if I’m wrong and I’ll change My answer and fix it for you

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2 years ago