When air pressure rapidly falls, what weather change usually occurs?

Two isotopes of lithium are found in nature Li6 has a mass of 6. 02u and Li7 has a mass of 7.02u . Use the atomic weight of lith

alexandr402 [8]

The isotope that is more abundant, given the data is isotope Li7

<h3>Assumption</h3>

Let Li6 be isotope A
Let Li7 be isotope B

<h3>How to determine whiche isotope is more abundant</h3>

Molar mass of isotope A (Li6) = 6.02 u
Molar mass of isotope B (Li7) = 7.02 u
Atomic mass of lithium = 6.94 u
Abundance of A = A%
Abundance of B = (100 - A)%

Atomic mass = [(mass of A × A%) / 100] + [(mass of B × B%) / 100]

6.94 = [(6.02 × A%) / 100] + [(7.02 × (100 - A)) / 100]

6.94 = [6.02A% / 100] + [702 - 7.02A% / 100]

6.94 = [6.02A% + 702 - 7.02A%] / 100

Cross multiply

6.02A% + 702 - 7.02A% = 6.94 × 100

6.02A% + 702 - 7.02A% = 694

Collect like terms

6.02A% - 7.02A% = 694 - 702

-A% = -8

A% = 8%

Thus,

Abundance of B = (100 - A)%

Abundance of B = (100 - 8)%

Abundance of B = 92%

SUMMARY

Abundance of A (Li6) = 8%
Abundance of B (Li7) = 92%

From the above, isotope Li7 is more abundant.

Learn more about isotope:

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4 0

2 years ago

what two bodies of water form a key transportation route connecting the interior of Canada to the Atlantic Ocean? and its scienc

hodyreva [135]

Answer:

Lake Ontario and St Lawrence Seaway

Explanation:

The Great Lakes are connected to the Atlantic Ocean through the St. Lawrence Seaway.

5 0

4 years ago

Explain why the elements of groups 1 and 7 are mostly used in<br> the form of compound

docker41 [41]

Group 1 and group 7 of element group consists of alkali metal, which are generally combined with other elements in nature, so they have properties of compound

8 0

3 years ago

Which parameter is indicative of how far and in what direction a reaction will progress?

nekit [7.7K]

Answer:

Option b, The change in free energy of the reaction (ΔG)

Explanation:

Gibbs free energy is a measure of amount of usable energy in the system.

It is related with enthalpy (H), entropy (S) and temprature (T) as:

G = H - TS

The Gibbs free energy change (ΔG) provide spontaneity of a chemical reaction.

If ΔG is negative, then reaction is spontaneous that means reaction is moving towards forward direction.

If ΔG is positive, then reaction is non-spontaneous that means reaction is moving in backward direction.

If ΔG is zero, then reaction is at equilibrium.

Change in enthalpy only gives informtion about heat involed in a chemical reaction, it does not give information about direction of the reaction.

So, among the given options, option b is correct.

6 0

3 years ago

what is the boiling point of the solution resulted from the dissolving of 32.5g of NaCl in 250.0g of water?

suter [353]

Answer:

The boiling point of this solution is 102.28 °C

Explanation:

<u>Step 1:</u> Data given

Mass of Nacl = 32.5 grams

Molar mass of NaCl = 58.45 g/mol

Mass of Water = 250 grams

Boiling point of water = 100°C

<u>Step 2: </u>Calculate number of moles

Number of moles = mass of NaCl / Molar mass of NaCl

Number of moles = 32.5 grams /58.45 g/mol = 0.556 moles

<u>Step 3:</u> Calculate molality

Molality = Number of moles / mass of water

Molality = 0.556 moles / 0.250 kg of water

Molality = 2.224 molal

NaCl releases twice as many moles of ions, the total molality of this solution is also twice: 4.448 molal

Step 4: Calculate boiling point

dT =( 0.512 C / molal)*4.448 molal)

dT = 2.28

The boiling point of this solution is 100 °C + 2.28 °C = 102.28 °C

8 0

3 years ago