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3 years ago

How has the taxonomy of organisms changed over time

Chemistry

1 answer:

neonofarm [45]3 years ago

8 0

Answer:

When scientist find new species that may have to change classification systems in order to accommodate them. DNA sequencing has also let us find out more about evolutionary relationships. The more recent the common ancestor, the more closely related the two species are.

Explanation:

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What is the order of reaction with respect to a and b for a reaction that obeys the rate law: rate = k[a]4[b]5?

spin [16.1K]

The order of reaction with respect to a is 4 and with respect to b is 5 for a reaction that obeys the rate law.

The order of reaction is equal sum of power of concentration of the each reactant present in the reaction that obeys the rate law . The order of individual reactant or species present in the rate law is equal to the power of the of concentration of the respective species or reactant .

Example : If rate law is given as,

rate = k $[a]^{4} [b]^{5}$

The order of reaction with respect to a is 4 and with respect to b is 5 for a reaction that obeys the rate law.

To learn more about order of reaction please click here

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3 0

2 years ago

If 200 g of benzoyl peroxide are used with 38 Kg of PTFE monomer, calculate the expected molecular weight of the polymer if (i)

den301095 [7]

Explanation:

The molecular weight of benzoyl peroxide is 242.23 g/mol.

Therefore, number of moles present in 200 g of benzoyl peroxide are as follows.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{200 g}{242.23 g/mol}$

= 0.825 mol

Molecular weight of PTFE is 100 g/mol.Hence, calculate the number of moles of PTFE in 38 kg as follows.

As 1 kg = 1000 g. So, 38 kg = 38000 g.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{38000 g}{100 g/mol}$

= 380 mol

As it is given that the initiator is 15% active. So, actual number of moles of benzoyl peroxide are as follows.

$0.15 \times 0.826$

= 0.124 mol

For combination, 1 mol of benzoyl peroxide produces 1 chain. Therefore, degree of polymerization will be calculated as follows.

DP = $\frac{380 mol}{0.124 mol}$

= 3065.33 mol

Average molecular weight of monomer is as follows.

$\frac{0.124}{0.124 + 380} \times MW_{benzoyl} + \frac{380}{0.124 + 380} \times MW_{PTFE}$

= 100.05 g/mol

Therefore, calculate the expected molecular weight of polymer as follows.

$3065.33 \times 100.05 g/mol$

= 306675.23 g/mol

Hence, for disproportion 1 mole benzoyl peroxide produces 2 chains.

DP = $\frac{2 \times 380}{0.124}$

= 6129.03

Therefore, calculate the expected polymer weight as follows.

$6129.03 \times 100.05$

= 613209.68 g/mol

Thus, we can conclude that the the expected polymer weight is 613209.68 g/mol.

6 0

3 years ago

White phosphorous has the chemical formula p4(s). a p4 molecule has 20 valence electrons. draw a lewis formula for a white phosp

aev [14]

The Lewis structure of P₄ is shown in 3-D form. The two bottom corner P atoms are facing right in front of us, one P atom behind the two, and one P above it. Each line represents 2 electrons. When you add the lone electrons, you get a total of 20 valence electrons.

Formal charge of each P: 5 - (2 +1/2*6) = 0

6 0

3 years ago

The size of camphor kept in store house gradually decrease in size after few а days?

zzz [600]

Answer:

Because it goes through the process of sublimation.

Explanation:

4 0

3 years ago

Water flows over Niagara Falls at the average rate of 2,400,000 kg/s, and the average height of the falls is about 50 m. Knowing

Zinaida [17]

Answer:

1) The power of Niagara Falls is 1.176 × 10⁹ W

2) The number of 15 W LED light bulbs it could power is 78.4 × 10⁶ light bulbs

Explanation:

1) The Niagara falls water mass flow rate = 2,400,000 kg/s

The height of the fall = 50 meters

The gravitational potential energy = Mass (kg) × height (m) × gravity (9.8 m/s²)

The power = The energy converted per second = Mass flow rate (kg/s) × height (m) × gravity (9.8 m/s²)

Therefore;

The power of Niagara Falls= 2,400,000 kg/s × 50 m ×9.8 m/s²= 1.176 × 10⁹ W

The power of Niagara Falls = 1.176 × 10⁹ W

2) The number, n, of 15 W LED light bulbs it could power is given by the relation;

n × 15 W = 1.176 × 10⁹ W

∴ n = 1.176 × 10⁹ W/(15 W) = 78.4 × 10⁶ light bulbs

The number of 15 W LED light bulbs it could power = 78.4 × 10⁶ light bulbs.

6 0

3 years ago