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3 years ago

How does the fossil record suggest common ancestry?

Chemistry

1 answer:

Jobisdone [24]3 years ago

6 0

Answer:

the first one is: Fossils provide evidence that organisms from the past are not the same as those found today, and demonstrate a progression of evolution. Scientists date and categorize fossils to determine when the organisms lived relative to each other.

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Which of these is a pure substance?

scoundrel [369]

B. Sugar is a pure substance.
It is sugar because sugar is made up of one atom or molecule.
A) penny is not correct because a penny is made up of copper, zinc, and tin.
C) ocean water is not correct because its made out of water (h2o) and salt.
D) iced tea is not correct because it takes many atoms to combine in order to make tea, then you have to add water and ice to make it an iced tea.

Hope this helps! :)

7 0

3 years ago

Read 2 more answers

Explain why clouds are generally observed to form only in the troposphere?

Paul [167]

Answer:

because we bystanders can see them through the sky and from the ground.

Explanation:

pls give brainliest im almost lvled up.

8 0

4 years ago

Read 2 more answers

The forensic technician at a crime scene has just prepared a luminol stock solution by adding 18.0 g of luminol into a total vol

Paladinen [302]

Answer:

1.36M

Explanation:

Luminol is a compound having the molecular formula as C8H7N3O2.

To know the molarity of the stock solution of Luminol, we shall carry out the following:

Step 1:

we shall calculate the number of mole in 18g of luminol. This is shown below:

Molar mass of C8H7N3O2 = (12x8) + (7x1 ) + (14x3) + (16x2)

= 96 + 7 + 42 + 32

= 177g/mol

Mass of C8H7N3O2 = 18g

Number of mole of C8H7N3O2 =..?

Mole = Mass /Molar Mass

Number of mole of C8H7N3O2 = 18/177 = 0.102 mole.

Step 2:

Conversion of 75.0 mL of H2O to Litre (L).

1000mL = 1L

Therefore, 75mL = 75/1000 = 0.075L

Step 3:

Determination of the molarity of the stock solution of Luminol.

Molarity is simply defined as the mole of solute per unit litre of water. Mathematically, it is represented as:

Molarity = mole /Volume

With the above formula, we can obtain the molarity of the stock solution of Luminol as follow:

Mole of C8H7N3O2 = 0.102 mole

Volume of water = 0.075L

Molarity =..?

Molarity = mole /Volume

Molarity = 0.102/0.075

Molarity = 1.36M

Therefore, the molarity of the stock solution of Luminol is 1.36M.

3 0

3 years ago

A 30. g sample of Aluminum was heated to 40. 0C and placed in a calorimeter containing 50. g of water at 21 0C. What is the fina

Darina [25.2K]

<u>Answer:</u> The final temperature will be $23^oC$

<u>Explanation:</u>

Calculating the heat released or absorbed for the process:

$q=m\times C\times (T_2-T_1)$

In a system, the total amount of heat released is equal to the total amount of heat absorbed.

$q_1=-q_2$

$m_1\times C_1\times (T_f-T_1)=-m_2\times C_2\times (T_f-T_2)$ ......(1)

where,

$C_1$ = specific heat of aluminium = $0.21 Cal/g^oC$

$C_2$ = heat capacity of water = $1Cal/g^oC$

$m_1$ = mass of aluminium = 30. g

$m_2$ = mass of water = 50. g

$T_f$ = final temperature of the system = ?

$T_1$ = initial temperature of aluminium = $40.^oC$

$T_2$ = initial temperature of the water = $21.^oC$

Putting values in equation 1, we get:

$30\times 0.21\times (T_f-40)=-50\times 1\times (T_f-21)\\\\56.3T_f=1302\\\\T_f=\frac{1302}{56.3}=23.13^oC=23^oC$

Hence, the final temperature will be $23^oC$

7 0

4 years ago

The three nuclides, U-233, U-235, and U-238, are isotopes of uranium because they have the same number of protons per atom and

Sophie [7]

Answer:

Electrons

Explanation:

Isotopes are atoms which have the same number of protons and electrons but a different number of neutrons. This is also the reason why there are no other changes in the atom but the mass of the specific atom changes.

Hope this helps :)

Merry Christmas. Have fun.

4 0

3 years ago