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3 years ago

How is the number 3.91 x 10 -4 expressed in regular numbers?

Chemistry

2 answers:

Shalnov [3]3 years ago

8 0

<span>D. 0.000391 is your answer because the decimal place moves 4 places to the left</span>

irga5000 [103]3 years ago

4 0

Answer : The correct option is, (D) 0.000391

Answer : The correct option is, (D) 0.000391Explanation :

Scientific notation : It is defined as the way or representation of expressing the number that are too big or too small that is written in the decimal form.

That means always written in the power of 10 form.

For example : 700 is written as, $7\times 10^2$ As we are given that the value of Avogadro’s number is, $3.91\times 10^{-4}$

This number is written in regular number as, 0.000391

Therefore, the correct option is, (D) 0.000391

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Choose two of the following scientists: Anton Lavoisier, John Dalton, JJ Thomson, Robert Millikan, Ernest Rutherford, James Chad

elixir [45]

Answer:

John Dalton:

John Dalton was the scientist who introduced atomic theory in the field of chemistry. Dalton worked on different gases and formulated this theory. The main points of Dalton's theory are:

Every element present is made up of atoms.
Atoms of an elements are have the same same properties whereas these properties are different for each element.
According to his theory, an atom could not be broken down.
Different atoms combine or get separated from each other during a chemical reaction.

Ernest Rutherford:

Ernest Rutherford is known as the father of nuclear physics due to his impressing research work on radioactivity of atoms. Rutherford was the first scientist to discover the nucleus of an atom and prove that the nucleus was charged. He also described that the electrons circle around the nucleus of an atom.

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3 years ago

The volume of a gas-filled balloon is 30.0 L at 313 K and 1520 mm Hg pressure. What would the volume be at standard temperature

pashok25 [27]

313 k
step-by-step-explanation

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3 years ago

What is the total mass of solute in 1000. grams of a solution having a concentration of 5 parts per million?

Art [367]

50 grams or 50,000 mili grams is the mass of solute in 1000 grams of a solution having a concentration of 5 parts per million.

Explanation:

Total mass of solution = 1000 grams or 1000 ml since 1 gram = 1 ml

concentration is 5 parts per million ( 5 mg in 1000 ml solution or 0.005 gram in 1000 ml)

the formula used for parts per million:

parts per million = $\frac{mass of solute (mg)}{volume of solution}$

putting the values in the equation:

parts per million = $\frac{mass of solute}{volume of solvent}$

0.005 x 1000 = mass of solute

50 grams= mass of solute

converting this into mg

50,000 mg. is the total mass of solute in 5ppm of 1000 ml solution.

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4 years ago

What is the reactivity trend of halogens?

RSB [31]

Reactivity trends of halogen:

1) Melting point and boiling points increased down the
group

2) Colour becomes darker.
E.g. Fluorine (pale yellow)
Chlorine (yellowish-green)
Bromine (reddish-brown)
Iodine (purplish-black)
Astatine (black)

3) The reactivity decreases down the group.
Reactivity:
F > Cl > Br > I > At

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3 years ago

A sample of oxygen gas occupies 3.60 liters at a pressure of 1.00 atm. If temperature is held constant, what will be the volume

Soloha48 [4]

Answer: The volume of the oxygen gas at a pressure of 2.50 atm will be 1.44 L

At constant temperature, the volume of a fixed mass of gas is inversely proportional to the pressure it exerts, then

PV = c

Thus, if the pressure increases, the volume decreases, and if the pressure decreases, the volume increases.

It is not necessary to know the exact value of the constant c to be able to use this law since for a fixed amount of gas at constant temperature, it is satisfied that,

P₁V₁ = P₂V₂

Where P₁ and P₂ as well as V₁ and V₂ correspond to pressures and volumes for two different states of the gas in question.

In this case the first oxygen gas state corresponds to P₁ = 1.00 atm and V₁ = 3.60 L while the second state would be P₂ = 2.50 atm and V₂ = y. Substituting in the previous equation,

1.00 atm x 3.60 L = 2.50 atm x y

We cleared y to find V₂,

V₂ = y = $\frac{1.00 atm x 3.60 L}{2.50 atm}$ = 1.44 L

Then, <u>the volume of the oxygen gas at a pressure of 2.50 atm will be 1.44 L</u>

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3 years ago