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3 years ago

Why is 99 not a prime number

Chemistry

2 answers:

Mice21 [21]3 years ago

6 0

Explanation:

99 is not a prime number because it can be multiplied by itself and by other numbers

99*1

9*11

goblinko [34]3 years ago

6 0

Answer:

A prime number is a number that can only be divisible by ±itself and ±1

but 99 can be divisible by ±3; ±11 => 99 isnt a prime number

Explanation:

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Assume that a milliliter of water contains 20 drops. How long, in hours, will it take you to count the number of drops

garri49 [273]

Answer:

126.18 hr

Explanation:

Data given:

1 mL of water = 20 drops

count rate = 10 drops/s

time in hours for one gallon = ?

Solution:

First we calculate number of mL (milliliter) of water in gallon

As we know

1 gallon = 3785.4 mL

As,

1 galon consist of 3785.4 mL of water, so now we count number of drops that contain 3785.4 mL of water

As we Know 1 mL water contain 20 drops then 3785.4 mL of water contain how many drops:

Apply unity formula

1 mL water ≅ 20 drops

3785.4 mL water ≅ X drops

Do cross multiplication

X drops of water = 20 drops x 3785.4 mL / 1 mL

X drops of water = 75708 drops

So, we come to know that one gallon contain 75708 drops of water and we have to calculate the time in hour to count these drops

First we calculate time in seconds

As we Know 10 drops water count in one second then how many seconds it will take to count 75708 drops

Apply unity formula

1 second ≅ 10 drops

X second ≅ 75708 drops

Do cross multiplication

X second = 1 second x 75708 drops / 10 drops

X second = 7570.8 second

So it take 7570.8 second to count 1 gallon water drops

Now convert seconds to hours

As,

60 seconds = 1 hr

7570.8 second = 7570.8 / 60 = 126.18 hr

So it take 126.18 hr to count 1 gallon water drops.

6 0

4 years ago

Explain how the understanding of atomic emission spectrum lead to development of the atomic theory

kiruha [24]

here we have to explain the development of the atomic theory by the atomic emission spectrum.

The most important aid in determining the structure of an atom has been study of radiation emitted and absorbed by the elements. The glowing atoms of an element emit radiations.

These are called the atomic spectra. This study helped to understand the structure of the atoms.

To explain the atomic spectra the Bohr's model was introduced. The postulates of the Bohr's model explain the fine spectrum of the atom up to the particle nature of the electrons.

Later some modification on the Bohr's postulates was made to explain the wave nature of the electrons as well. But the atomic spectra is best be understood by the Bohr's atomic model which developed the atomic theory.

Thus the understanding of emission spectrum of atom to develop the atomic theory is explained.

8 0

4 years ago

Copper has two naturally occurring isotopes. Cu−63 has a mass of 62.939 amu and relative abundance of 69.17%.

fiasKO [112]

The answer is 64.907 amu.

The atomic mass of an element is the average of the atomic masses of its isotopes. The relative abundance of isotopes must be taken into consideration, therefore:
atomic mass of copper = atomic mass of isotope 1 * abundance 1 + atomic mass of isotope 2 * abundance 2

We know:
atomic mass of copper = 63.546 amu
The atomic mass of isotope 1 is: 62.939 amu
The abundance of isotope 1 is: 69.17% = 0.6917
The atomic mass of isotope 1 is: x
The abundance of isotope 2: 100% - 69.17% = 30.83% = 0.3083

Thus:
63.546 amu = 62.939 amu * 0.6917 + x * 0.3083
63.546 <span>amu = 43.535 amu + 0.3083x
</span>⇒ 63.546 amu - 43.535 amu = 0.3083x
⇒ 20.011 amu = 0.3083x
⇒ x = 20.011 amu ÷ 0.3083 = 64.907 amu

7 0

3 years ago

What happens if you put a cat in the microwave?

Wewaii [24]

She said that the exposure to the radiation in the microwave would have cooked the animal's internal organs. She said: 'It is a horrific case in the fact that the death of the cat would have been prolonged and it is unimaginable what it would have gone through taking some time to die.

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3 years ago

Oxygen-Carbon Dioxide Exchange

leonid [27]

Answer:

Answer is below with the steps in order

Explanation:

4) Blood picks up carbon dioxide from the body

7) Heart pumps carbon dioxide rich blood to the lungs

8) Inhale

9) Nose traps germs in air

10) Air moves down the trachea

3) Air moves through bronchi into the bronchioles

6) Alveoli receive oxygen pass to blood

9) Oxygen passes into the blood

11) Alveoli receives carbon dioxide from the blood

12) Oxygen-rcih blood flows to the heart

3) Carbon Dioxide moves from bonchioles to bronchi

13)Carbon dioxide flows up

1) Heart pumps oxygen-rich blood to the body

The last <em>four of five</em> steps could be switched up a little bit since it all happens synchronously, but this is the most accurate interpretation.

8 0

3 years ago

Why is 99 not a prime number​

Why is 99 not a prime number