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3 years ago

Animal cells do NOT have cell walls. Why do you think this is an advantage?

2 answers:

7 0

Animal cells do not have cell walls because they do not need them. Cell walls, which are found in plant cells, maintain cell shape, almost as if each cell has its own exoskeleton. This rigidity allows plants to stand upright without the need for bones .

andriy [413]3 years ago

6 0

Answer:

Because they don't need them , cell wall which are found in cell, maintain cell shape almost as if each cell has it's own exoskeleton ame this them to stand upright without the need for bones .

Explanation:

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How many moles are there in 32.4 grams of Na

Natalija [7]

Divide that my the molar mass which is 23 so 1.4087 g

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3 years ago

Which source of water pollution would be the hardest to trace and control?

Alex Ar [27]

Answer:

Nonpoint pollution is harder to control

Explanation:

Nonpoint pollution is harder to control because they include runoff from farms, golf courses, construction sites, roads. Whereas the single origin of the pollution is harder to trace.

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3 years ago

HELP DUE MONDAY!!<br> Don’t understand

Katyanochek1 [597]

Answer:

Concept: Chemical Analysis

You need to start by graphing the data and then analyzing it.
We can see that the horse has a distance in meters of 980 at the end of the 10 seconds hence it is the fastest.
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3 years ago

A specific steroid has a λmax of 257 nm and a molar absorptivity ε of 11 , 500 L mol − 1 cm − 1 . What is the concentration of t

joja [24]

Answer:

$7.83\times 10^{-6} M$ is the concentration of the compound in a solution.

Explanation:

Using Beer-Lambert's law :

Formula used :

$A=\epsilon \times C\times l$

Where:

A = absorbance of solution

C = concentration of solution

l = path length

$\epsilon$ = molar absorptivity coefficient

We have:

C = ? , l = 1.00 cm, A = 0.090

$\epsilon = 11,500 L/(mol cm)$

$C=\frac{A}{\epsilon l}=\frac{0.090}{11,500 L/(mol cm)\times 1.00 cm}$

$C=7.83\times 10^{-6} M$

$7.83\times 10^{-6} M$ is the concentration of the compound in a solution.

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3 years ago

Give the formula for an ionic compound formed from each pair of ions

Vera_Pavlovna [14]

Please, find the complete question in the picture attached.

Answer:

1. Na₂O

2. AlF₃

3. MgO

4. Ca₃P₂

Explanation:

1. Na⁺ and O²⁻

An ionic compound will be formed when two ions of opposite charge attract each other.

The positive ion is called cation and the negative ion is called anion.

Thus, every ionic compound has a cation and an anion electrostatically bonded.

The ions must combine in a proportion that genders a neutral compound: so you must have as many cations as negative charge has one anion and as many anions as positive charge has one cation.

This is, if the cation has charge +x, there will be x anions, and if the anion has charge -y, there will be y cations.

Simbolically:

$Cation:A^{+x}\\ \\ Anion:B^{-y}\\ \\ Compound:A_yB_x$

As you see, the subscripts for each element in the chemical formula are obtained by the exchage of the charges of the ions.

Then, for Na⁺ and O²⁻, the subscript for Na will be 2 and the subscript for O will be 1; and the formula of the ionic compound formed by this pair ot ions is:

Na₂O

2. Al³⁺ and F⁻

The subscript of Al will be 1 (because the F ion has charge 1-, and the subscript of F will be 3 (because the Al ion has charge +3).

Thus the ionic compound formed by this pair of ions is:

AlF₃

3. Mg²⁺ and S²⁻

The charge 2+ from Mg atom wil become the subscript 2 of S atom, and the charge 2- will become the subscript 2 of Mg atom:

That results in the formula: Mg₂S₂

Except for some special compounds, the chemical formula is simplified, dividing by the least common denominator. In this case, that means that the two 2 subscripts are simplified to 1, and the final chemical formula for the ionic compound formed by this pair of ions is:

4. Ca²⁺ and P³⁻

The charge 2+ from Ca will become subscript 2 for P and the charge 3- whill become subscript 3 for Ca.

Hence, the ionic compound formed by these two ions is:

Ca₃P₂

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3 years ago