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3 years ago

Which of the following statements is FALSE?

Chemistry

1 answer:

Alborosie3 years ago

6 0

Answer:

The answer to your question is: letter E

Explanation:

A. This option is correct, the n = 3 shell only has subshells: s, p and d, and shell n = 4 or 5 have f subshell.

B. This option is true in subshell p could be at most 6 electrons and 3 suborbitals.

C. This option is correct orbital "s" is a sphere.

D. This option is correct, in subshell d could be at most 10 electrons and 5 orbitals.

E. This option is false, hydrogen only has 1 electron and then one subshell (s).

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What are two ways that scientists can report results of their experiments

tiny-mole [99]

Answer: Scientists often communicate their research results in three general ways. One is to publish their results in peer-reviewed journals that can be ready by other scientists. Two is to present their results at national and international conferences where other scientists can listen to presentations.

Explanation:

7 0

3 years ago

An airplane travels 2100 km at 1000km/hE. It encounters a wind and slows to 800 km/h E for the next 1300 km. What is the average

Deffense [45]

Answer:

The average velocity of the airplane for this trip is 1684.21 km/h

Explanation:

Average velocity is the rate of change of displacement with time. That is,

Average velocity = $\frac{Displacement }{Change in time}$ = Δx / Δt = $\frac{x2 - x1}{t2 - t1}$

Now we will calculate the time taken by the airplane for the first motion before it encounters a wind.

From,

Velocity = $\frac{Distance traveled}{Time taken}$

Time = $\frac{Distance traveled}{Velocity}$

Therefore, Time = $\frac{2100km }{1000km/h}$

Time = 2.1h

This is the time taken before the airplane encounters a wind.

Hence, t1 = 2.1h

Now, For the time taken by the airplane when it encounters a wind

Also from,

Velocity = $\frac{Distance traveled}{Time taken}$

Time = $\frac{Distance traveled}{Velocity}$

Therefore, Time = $\frac{1300km }{800km/h}$

Time = 1.625h

Hence, t2 = 1.625h

Now, to calculate the average velocity

Average velocity = $\frac{x2 - x1}{t2 - t1}$

x1= 2100, x2= 1300, t1= 2.1h and t2= 1.625h

Hence, Average velocity = $\frac{1300 - 2100}{1.625 - 2.1}$

Average velocity = 1684.21 km/h

7 0

3 years ago

Explain the term "amphoteric"

Natali5045456 [20]

A substance either an ion or a molecule that can act either an acid or a base depending on a medium is called Amphoteric. Some metals like zinc, tin, copper and aluminium which produce either metal oxides or hydroxides are examples of amphoteric. During the Amphoterism, the metal compound acts either an acid or a base depending on their oxidation state.

4 0

3 years ago

A buffer solution contains 0.479 M NaHCO3 and 0.342 M Na2CO3. Determine the pH change when 0.091 mol HNO3 is added to 1.00 L of

pshichka [43]

Answer:

ΔpH = 0.20

Explanation:

The buffer of HCO₃⁻ + CO₃²⁻ has a pka of 10.2

HCO₃⁻ ⇄ H⁺ + CO₃²⁻

There are 0.479moles of NaHCO₃ and 0.342moles of Na₂CO₃.

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.342mol / 0.479mol

pH = 10.05

NaOH reacts with HCO₃⁻ producing CO₃²⁻, thus:

NaOH + HCO₃⁻ → CO₃²⁻ + H₂O + Na⁺

0.091 moles of NaOH produce the same moles of CO₃²⁻ and consume HCO₃⁻. Moles of these species are:

CO₃²⁻: 0.342mol + 0.091mol: 0.433mol

HCO₃⁻: 0.479mol - 0.091 mol: 0.388mol

Using Henderson-Hasselbalch formula:

pH = pka + log [Base] / [Acid]

pH = 10.2 + log 0.433mol / 0.388mol

pH = 10.25

That means change of pH, ΔpH is:

ΔpH = 10.25 - 10.05 = 0.20

I hope it helps!

3 0

3 years ago

The diagram shows Earth's position in its orbit around the Sun at the beginning of each season

alexdok [17]

Answer: the answer is option 3. C

Explanation:

8 0

3 years ago