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3 years ago

The quinine in tonic water shines a strange blue-white colour when lit with UV light. Explain what is happening here.

Chemistry

1 answer:

Alecsey [184]3 years ago

5 0

Answer:

Here's what I get.

Explanation:

Quinine contains phosphors, substances that glow when they are hit with certain wavelengths of light.

The phosphors in quinine absorb UV light, which is invisible to our eyes.

Electrons in the phosphors absorb the UV energy and are excited to higher energy levels.

When the electrons drop back to lower energy levels, they emit some of this energy as a glowing blue visible light.

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What do Potassium and Krypton have in common and what are their differences based on their location on the periodic table?

Kamila [148]

Potassium (K) and Krypton (Kr) are in the same period, so they have the same number of electron shells. Potassium is more reactive than Krypton because it only has one valence electron.

K and Kr are both in Period 4, so they each have the n = 1, 2, 3, and 4 shells. Kr is less reactive than K because it already has a complete octet.

“Potassium (K) and Krypton (Kr) are in the same period, so they have the same number of electron shells. Krypton is more reactive than Potassium because it has a full outer shell” is <em>incorrect </em>because having a full outer shell means that the element is unreactive.

“Potassium (K) and Krypton (Kr) are in the same group, so they have the same number of valence electrons. They have different numbers of electron shells” is <em>incorrect </em>for three reasons:

1. K is in Group 1 and Kr is in Group 18.

2. K has one valence electron, and Kr has eight valence electrons.

3. They have the same number of electron shells.

1. K and Kr have different numbers of valence electrons.

2. They have the same number of electron shells.

8 0

3 years ago

Could a man with type B blood and a woman with type AB produce a child with type O blood?

Luda [366]

Answer:

The possible genotypes of a man with blood type B are BB or BO and the genotype of a woman with blood type AB is AB. The child would receive an A allele or a B allele from the mother and a B allele or an O allele from the father. Therefore, the child could not possibly be of blood type O.

Explanation:

thank me later

4 0

3 years ago

What pressure, in atm, would be exerted by 0.023 grams of oxygen (O2) if it occupies 31.6 mL at 91

Vikentia [17]

Answer: A pressure of 0.681 atm would be exerted by 0.023 grams of oxygen $(O_2)$ if it occupies 31.6 mL at $91^{o}C$ .

Explanation:

Given : Mass of oxygen = 0.023 g

Volume = 31.6 mL

Convert mL into L as follows.

$1 mL = 0.001 L\\31.6 mL = 31.6 mL \times \frac{0.001 L}{1 mL}\\= 0.0316 L$

Temperature = $91^{o}C = (91 + 273) K = 364 K$

As molar mass of $O_2$ is 32 g/mol. Hence, the number of moles of $O_2$ are calculated as follows.

$No. of moles = \frac{mass}{molar mass}\\= \frac{0.023 g}{32 g/mol}\\= 0.00072 mol$

Using the ideal gas equation calculate the pressure exerted by given gas as follows.

PV = nRT

where,

P = pressure

V = volume

n = number of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the value into above formula as follows.

$PV = nRT\\P \times 0.0316 L = 0.00072 mol \times 0.0821 L atm/mol K \times 364 K\\P = \frac{0.00072 mol \times 0.0821 L atm/mol K \times 364 K}{0.0316 L}\\= 0.681 atm$

Thus, we can conclude that a pressure of 0.681 atm would be exerted by 0.023 grams of oxygen $(O_2)$ if it occupies 31.6 mL at $91^{o}C$ .

4 0

3 years ago

Balance this equation: Al+ HNO3 ---- H2 + Al(NO3)3

romanna [79]

Answer:

2Al+ 6HNO3 ---- 3H2 + 2Al(NO3)3

Explanation:

Put coefficient a,b,c, and d for calculation:

a Al + b HNO3 = c H2 + d Al(NO3)3

for Al: a = d

for H: b = 2c

for N: b = 3d

for O: 3b = 9d

Suppose a=1, then d=1, b=3, c=3/2

multiply 2 to make all natural number, a=2, then b=6, c=3, d=2

6 0

3 years ago

Which sequence of events is required to form a limestone cave where you can walk around and observe cave formations, such as sta

N76 [4]

Answer:

Which sequence of events is required to form a limestone cave where you can walk around and observe cave formations, such as stalactites? (Note: stalactites hang from the ceiling - they have to hold on tight to the roof.)

A geological sequence of events as involving the lowering of the water table to expose cave structures where stalactites and stalagmites form which is described as follows,

Explanation:

1. Acidic percolated water formed cavities of solution beneath the natural water table known as phreatic zone

2. After the passage of time there is a drop in the water table dropped forming caves from cavities

3. These caves, which are air filled voids that contains adequate environment for forming stalactites and stalagmites and where they are found

5 0

3 years ago