Can someone help me!!

If silicon has a charge of -4, how many electrons does it have

Ksenya-84 [330]

It has 4 because electrons are negative.

4 0

3 years ago

BigorU [14]

Answer:

3.34x10¹⁶ molecules of aspirin are in a drop of blood

Explanation:

The recomended dose of aspirin in blood is 100.0μg/mL =

1x10⁻⁴g aspirin / mL of blood.

In a drop (0.100mL) there are:

0.100mL ₓ (1x10⁻⁴g aspirin / mL of blood) = 1x10⁻⁵g aspirin.

Molecular mass of aspirin is:

9C = 12.01g/mol ₓ 9 = 108.09g/mol

8H = 1.01g/mol ₓ 8 = 8.08g/mol

4O = 16g/mol ₓ 4 = 64g/mol

108.09 + 8.08 + 64 = 180.17g/mol

Thus, moles of aspirin in 1x10⁻⁵g are:

1x10⁻⁵g ₓ (1mol / 180.17g) = 5.55x10⁻⁸ moles of aspirin

In 1 mole, you have 6.022x10²³ molecules, thus:

5.55x10⁻⁸ moles of aspirin ₓ (6.022x10²³ molecules / 1 mole ) =

<h3>3.34x10¹⁶ molecules of aspirin are in a drop of blood</h3>

7 0

3 years ago

Photosynthesis occurs. How do plants get the carbon dioxide they need for photosynthesis?

igomit [66]

Why wouldn’t that make a difference, hola mi, polo el coron

7 0

3 years ago

Read 2 more answers

How many moles of HCl are there in 75.0 mL of 0.325 M HCI?

dangina [55]

Answer: The moles of HCl are 0.0244

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

$Molarity=\frac{n\times 1000}{V_s}$

where,

n = moles of solute = ?

$V_s$ = volume of solution in ml

Now put all the given values in the formula of molality, we get

$0.325=\frac{moles\times 1000}{75.0}$

$moles=0.0244$

Therefore, the moles of HCl are 0.0244

3 0

3 years ago

Compare and contrast Lamarck's and Darwin's theories of change over time.36a. What are the similarities? What are the difference

frosja888 [35]

Answer:

See explanation

Explanation:

Lanark proposed a theory of evolution hinged on use and disuse of body parts. This is a theory that upholds the transfer of acquired traits to offsprings. Darwin's theory of evolution was rather based on natural selection or 'survival of the fittest'. Darwin's theory has more evidence backing it compared to Lamarck's theory. The field of genetics which appeared long after Darwin's death confirmed that inherited traits are indeed passed from parents to offsprings. These inherited traits are usually those that give organisms an edge over others in their environment.

Earthworms are brown and not green or beige because, the brown earthworms have the same colour as the soil and are better enabled to escape from predators. From Darwin's theory, the brown earthworms are the 'fittest' hence they survive in their environment. Lamarck's theory may approach the matter from the point that earthworms move with their bodies on the soil more frequently, hence they 'acquired' the brown colour and passed it on to their offspring.

From the activity, "Hiding in the Background", individual worms spent their entire life cycle in either green or beige colour. Their colour didn't change as a result of the environment where they lived, rather the green earthworms were more in number, not particularly because of any specific changes the earthworms themselves had undergone, but because most of their predators concentrated on eating the beige worms. As a result of this, there were many green worms when the next generation began compared to the number of beige worms. Hence, there were more green earthworms.

8 0

4 years ago