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3 years ago

When did these geologic processes occur?

1 answer:

6 0

Time Scales. As discussed before, the Solar System began to form about 6 billion years ago and the Earth and other planets about 4.5 billion years ago. Geologic processes have operated on the Earth ever since.

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A lead ball is added to a graduated cylinder containing 50.6 ml of water, causing the level of the water to increase to 93.0 mL.

Kamila [148]

42.4 ml is the volume in milliliters of the lead ball if a lead ball is added to a graduated cylinder containing 50.6 ml of water.

<h3>What is a graduated cylinder?</h3>

A tall narrow container with a volume scale is used especially for measuring liquids.

The graduated cylinder contains water

mL is a volume unit.

Water volume = 50.6 ml

The lead ball caused an increase in volume from 50.6 ml to 93.0 mL.

The new volume is the lead ball volume plus the original water volume :

Final volume = Vlead ball+ Water original volume

$93.0 mL= V_(lead ball) +50.6 ml$

$V_(lead ball) = 93.0 mL - 50.6 ml$

$V_(lead ball) = 42.4 ml$

Hence, 42.4 ml is the volume in milliliters of the lead ball.

Learn more about the graduated cylinder here:

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4 0

2 years ago

Draw the Lewis dot structure for RbIO2. Include all hydrogen atoms and nonbonding electrons. Show the formal charges of all atom

Rzqust [24]

Answer : The Lewis-dot structure of $RbIO_2$ is shown below.

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The given molecule is, $RbIO_2$

As we know that rubidium has '1' valence electrons, iodine has '7' valence electrons and oxygen has '6' valence electrons.

Therefore, the total number of valence electrons in $RbIO_2$ = 1 + 7 + 2(6) = 20

As we know that $RbIO_2$ is an ionic compound because it is formed by the transfer of electron takes place from metal to non-metal element.

7 0

3 years ago

Calculate to three significant digits the density of chlorine pentafluoride gas at exactly and exactly . You can assume chlorine

slega [8]

Answer:

Density is 6.16g/L

Explanation:

... at exactly -15°C and exactly 1atm...

Using general gas law:

PV = nRT

We can find density (Ratio of mass and volume) in an ideal gas as follows:

P/RT = n/V

To convert moles to grams we need to multiply the moles with Molar Weight, MW:

n*MW = m

n = m/MW

P/RT = m/V*MW

P*MW/RT = m/V

Where P is pressure: 1atm;

MW of chlorine pentafluoride: 130.445g/mol

R is gas constant: 0.082atmL/molK

And T is absolute temperature: -15°C+273.15 = 258.15K

Replacing:

P*MW/RT = m/V

1atm*130.445g/mol / 0.082atmL/molK*258.15K = m/V

6.16g/L = m/V

<h3>Density of the gas is 6.16g/L</h3>

7 0

3 years ago

PLEASE SOMEBODY EXPLAIN THIS :(((

djverab [1.8K]

Answer:

$\boxed{ \sf \: R_f \: value \: of \: sample \: 1 =0.3142}$

<h3>Explanation:</h3>

In Analytical Chemistry chromatography is widely used for the separation of samples.

In thin layer chromatography, the mixture of components are separated on the basis of their polarity.
The solvent solution(mobile phase) that we use are non polar & silica gel( TLC paper made of/stationary phase) are polar.
Consider the mixture we have taken consist of two samples having large polar difference.
Due to opposite nature of silica gel(polar) & solvent solution (non polar) the movement become easy & due to capillary action solvent solution rise to the top.
The mixture of sample we have taken, the sample have less polarity have high peak or they travel more distance than that of more polar sample when they dipped into the solution.

In the given diagram, mixture of 8 samples are separated on the basis of their polarity, the distance travelled by solvent is 35 mm, distance travelled by sample 1 is 11 mm & similarly distance travelled by sample 2,3,4,5,6,7 are 15,31,4,22,25,33 in mm respectively.

Rf Value: Rf value is retention factor which tells about relative absorption of each sample & range of Rf value is 0-1.

Formula to calculate Rf value is

$\sf R_f \: value = \frac{distance \: moved \: by \: sample}{distance \: moved \: by \: solvent}$

Now, solving for Rf value of sample 1

Given:

Distance moved by sample 1 = 11 mm

Distance movedby solvent = 35 mm

To find:

Rf value of sample 1 = ?

Solution:

Substituting the given data in above formula,

$\small \sf R_f \: value = \frac{distance \: moved \: by \: sample \: 1}{distance \: moved \: by \: solvent} \\ \small \sf R_f \: value = \cancel\frac{11 \: mm}{35 \: mm} = 0.3142$

$\small \boxed{ \sf \: R_f \: value \: of \: sample \: 1 =0.3142}$

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4 0

2 years ago

Solid sodium reacts violently with water producing heat, hydrogen gas and sodium hydroxide. How many molecules of hydrogen gas a

nignag [31]

Find the number of moles of sodium you have:
n = m/M where m is your 20g of sodium and M is 22.99 g/mol. 

Look at the stoichiometry of the equation - it's 2:2 when you are producing NaOH. So if you took 1 mole of Na, it'd produce 1 mole of NaOH (as the ratio is equal). 

That means that your moles of sodium is equal to the moles of NaOH produced. Use the molar mass of NaOH - which is 39.998 g/mol along with your calculated number of moles to get the mass (the formula rearranges to m = nM). 

This figure is the theoretical yield - what you would get if every last mole of sodium was converted into NaOH. 

What you get in practice is the experminetal yield, and the percentage yield is the experimental yield divided by the theoretical yield - and then multiplied by 100%.

4 0

3 years ago

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