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3 years ago

Atoms of different elements have a different mass and volume. Why is the statement true?

1 answer:

6 0

Answer:different elements have different number of electrons and shells/orbits thatswhy it have different atomic mass and size.

Explanation:

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Earth is approximately 1.5 x 10^8 km from the sun the. How far is earth from the sun meters

Zielflug [23.3K]

Answer:

${ \tt{1 \: km = 1000m}} \\ { \tt{1.5 \times {10}^{8} km = (\frac{1.5 \times {10}^{8} \times 1000 }{1} )m}} \\ = 1.5 \times {10}^{11} \: metres$

4 0

3 years ago

Which statement is true of magnets

Harrizon [31]

The statement that is true about magnets is ''Similar poles of a magnet repel each other.''

<h3>What are the characteristics of magnet?</h3>

All magnets have both north and south poles. Opposite poles attract each other, whereas the similar poles repel each other. When you rub a piece of iron along a magnet, this force creates a magnetic field.

So we can conclude that The statement that is true about magnets is ''Similar poles of a magnet repel each other.''

Learn more about magnet here: brainly.com/question/14997726

#SPJ1

4 0

2 years ago

The activation energy of an uncatalyzed reaction is 70 kJ/mol. When a catalyst is added, the activation energy (at 20 °C) is 42

denis23 [38]

Answer:

T = 215.33 °C

Explanation:

The activation energy is given by the Arrhenius equation:

$k = Ae^{\frac{-Ea}{RT}}$

<u>Where:</u>

k: is the rate constant

A: is the frequency factor

Ea: is the activation energy

R: is the gas constant = 8.314 J/(K*mol)

T: is the temperature

We have for the uncatalyzed reaction:

Ea₁ = 70 kJ/mol

And for the catalyzed reaction:

Ea₂ = 42 kJ/mol

T₂ = 20 °C = 293 K

The frequency factor A is constant and the initial concentrations are the same.

Since the rate of the uncatalyzed reaction (k₁) is equal to the rate of the catalyzed reaction (k₂), we have:

$k_{1} = k_{2}$

$Ae^{\frac{-Ea_{1}}{RT_{1}}} = Ae^{\frac{-Ea_{2}}{RT_{2}}}$ (1)

By solving equation (1) for T₁ we have:

$T_{1} = \frac{T_{2}*Ea_{1}}{Ea_{2}} = \frac{293 K*70 kJ/mol}{42 kJ/mol} = 488. 33 K = 215.33 ^\circ C$

Therefore, we need to heat the solution at 215.33 °C so that the rate of the uncatalyzed reaction is equal to the rate of the catalyzed reaction.

I hope it helps you!

4 0

4 years ago

The body of knowledge that deals with Earth and its place in the universe is called _____________?

lakkis [162]

Answer:

Cosmology is a branch of astronomy that involves the origin and evolution of the universe, from the Big Bang to today and on into the future. According to NASA, the definition of cosmology is "the scientific study of the large scale properties of the universe as a whole."

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3 years ago

Question 3<br> 6.06 X 103 L<br> How many significant figures are there

VashaNatasha [74]

There should be 22 figures .

4 0

3 years ago