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3 years ago

The number of water molecules present in a drop of water at room temperature

1 answer:

8 0

Water drops come in different sizes.
Let's imagine a drop weighs a quarter of a gram.
The molar mass of water is about 18g/mol, which means that 6.02 x 10^23 water molecules (AKA a mole of water molecules) weigh about 18 grams.
A quarter of a gram is 1/72 of 18, so it contains 1/72 times 6.02 x 10^23 molecules. That equals 8361111111111110000000 molecules.
In scientific notation that is... 8.36 x 10^21 molecules.

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What is acid rain and why is it a concern?

Vikki [24]

Answer:

acid rain is a type of mixture that has a chemical substance that harms people, and can lead to possibly death.

Explanation:

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4 years ago

To aid in the prevention of tooth decay, it is recommended that drinking water contains 0.900 ppm fluoride (F-). A) How many g o

Romashka-Z-Leto [24]

Answer:

a) <u>1.740 g</u> of F- must be added to a cylindrical water reservoir

b) Grams of sodium fluoride, NaF, that contain this much fluoride:

3.84 g

Explanation:

Step 1. calculate the volume of the tank:

Volume of cylinder =

$\pi r^{2}h$ ,

Here r = radius of the cylinder = d/2

h = depth = 21.80m

$r=\frac{d}{2}$

$=\frac{3.36x10^{2}}{2}$

= 168 m

Volume =

$=\frac{22\times 168^{2}\times 21.80}{7}$

$=1.93\times 10^{6} m^{3}$

2.Convert ppm to g/m3 and Solve for mass of F-

$1ppm = 1g/m^{3}$

$0.9ppm = 0.9g/m^{3}$

Because both ppm and g/m3 are same quantity .

$g/m^{3} =\frac{mass\ of\ F-(g)}{Volume\ m^{3}}\times 10^{6}$

$0.9 =\frac{mass\ of\ F-}{1.93\times 10^{6} m^{3}}\times 10^{6}$

$mass\ of\ F- =1.740g$

mass of F- required = 1.740 g

3. Apply <u>mole concept </u>to calculate grams of sodium fluoride produced

mass of 1 mole of F2 = 38 g

mass of 1 mole of NaF = 42 g

(from periodic table calculate molar mass)

$2Na+F_{2}\rightarrow 2NaF$

Here 1 mole of F2 produce = 2 mole of NaF

So,

38 g of F2 produce = 2 x 42 g of NaF

38 g of F2 produce = 84 g of NaF

1 g of F2 produce = 84/38 g of NaF

1.74 g F2 produce =

$\frac {84}{38}\times 1.74$

1.74 g F2 produce = 3.84 g of NaF

3.84 g of NaF is produced

3 0

3 years ago

What type of reaction occurs initially with sodium azide when airbags initially deploy.

Luden [163]

The chemical at the heart of the air bag reaction is called sodium azide, or NaN3. CRASHES trip sensors in cars that send an electric signal to an ignitor. The heat generated causes sodium azide to decompose into sodium metal and nitrogen gas, which inflates the car's air bags.

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3 years ago

Atoms have been traditionally viewed as being composed of three different types of particles: protons, neutrons, and electrons.

sattari [20]

Answer:

See explanation

Explanation:

Before the advent of the wave-particle duality theory proposed by Louis de Broglie, there was a sharp distinction between mater and waves.

However, Louis de Broglie introduced the idea that mater could display wave-like properties. Erwin Schrödinger developed this idea into what is now known as the wave mechanical model of the atom.

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This idea has been the longest surviving atomic model and has greatly increased our understanding of atoms.

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3 years ago

___________ would albumin expect to dissociate into individual ions and increase the number of osmols/mol in solution.

Lubov Fominskaja [6]

Answer: Check explanation please.

Explanation:

Before diving into the question,let us consider some important facts and definitions.

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OSMOLARITY can be calculated using; Σ(osmotic coefficient × number of ion × the solute molar concentration).

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Also, if we have the osmotic coefficient to be between zero and one, there is going to be great DISSOCIATION.

6 0

3 years ago

The number of water molecules present in a drop of water at room temperature​

The number of water molecules present in a drop of water at room temperature