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3 years ago

What two methods are used for determining the age of rocks and fossils?

Chemistry

1 answer:

Alexandra [31]3 years ago

7 0

Explanation:

first one because absolute dating is a thing for rock layers

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What’s the physical properties of a molecular solid, in regards to its physical properties of formation?

Anastasy [175]

It has a fixed mass
it does not change with the shape of the container
it cannot be compressed
it has fixed atom and molecules and limited to very small displacement
only vibrational motion occur in the molecules of solid .

7 0

3 years ago

Can someone help Plz

Marrrta [24]

Answer: A. 1.60 liters

Explanation:

$2Na_2O_2+2CO_2\rightarrow 2Na_2CO_3+O_2$

As can be seen from the balanced chemical equation, 2 moles of $CO_2$ produce 1 mole of $O_2$ .

According to Avogadro's law, every 1 mole of the gas occupies 22.4 liters at STP.

Thus $2$ moles of $CO_2$ occupies $22.4\times 2=44.8L$ at STP and produce 1 mole of $O_2$ i.e. 22.4 L

44.8 L of $CO_2$ will produce 22.4 L of $O_2$

Thus $3.20L$ of $CO_2$ will produce $\frac{22.4}{44.8}\times 3.20=1.60L$

6 0

3 years ago

The average atomic mass of Eu is 151.96 amu. There are only two naturally occurring isotopes of europium, Eu with a mass of 151.

earnstyle [38]

Answer:

The percentage abundance of Eu isotopes are 52 % and 48 % .

Explanation:

The formula for the calculation of the average atomic mass is:

$Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})$

Given that:

Since the element has only 2 isotopes, so the let the percentage of first be x and the second is 100 -x.

For first isotope,:

% = x %

Mass = 151.0 amu

For second isotope :

% = 100 - x

Mass = 153.0 amu

Given, Average Mass = 151.96 amu

Thus,

$151.96=\frac{x}{100}\times {151.0}+\frac{100-x}{100}\times {153.0}$

Solving for x, we get that:

x = 52 %

<u>Thus percentage abundance of Eu isotopes are 52 % and 48 % .</u>

7 0

3 years ago

Do the molecules in a desk have energy?

Harrizon [31]

Everything requires energy to move. If the desk is moving, then it has energy.

6 0

3 years ago

What electrically neutral atom will have an electron configuration of 1s2 2s2 2p4?

abruzzese [7]

Answer:- oxygen.

Explanations:- The electronic configuration is given and we are asked to figure out the electrically neutral atom that will have the electron configuration, $1s^22s^22p^4$ .

The sum of electrons for this electron configuration is 8. If we look at the periodic table then 8 is the atomic number of oxygen.

So, the electrically neutral atom for the given electron configuration is oxygen.

6 0

3 years ago