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3 years ago

This thin layer surrounds all cells and controls what materials can enter or exit.

Chemistry

2 answers:

scoundrel [369]3 years ago

7 0

Answer:

Explanation:

D) Cell memberane

MatroZZZ [7]3 years ago

3 0

I think it’s D) cell membrane
Hope this helps
Have a good day

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Aluminum reacts with oxygen to produce aluminum oxide which can be used as an adsorbent, desiccant or catalyst for organic react

pishuonlain [190]

The balance chemical equation is as follow,

2 Al + 3 O₂ → Al₂O₃

Aluminium is the Limiting Reagent,
As,
107.92 g Al required = 96 g of O₂
Then,
82.49 g of Al will require = X g of O₂
Solving for X,
X = (82.49 g × 96 g) ÷ 107.92 g

X = 73.37 g of O₂
But,
We are provided with 117.65 g of O₂, So, it is provided in excess and 44.28 g of it will remain unreacted.

Solving for Amount of Al₂O₃ formed,
As,
107.92 g of Al produced = 203.92 g of Al₂O₃
Then,
82.49 g of Al will produce = X g of Al₂O₃
SOlving for X,
X = (82.49 g × 203.92 g) ÷ 107.92

X = 155.86 g of Al₂O₃

8 0

4 years ago

The ___ is the number of protons in the nucleus of an atom of an element. Fill in the blank.

Maurinko [17]

The atomic number is the number of protons in the nucleus

8 0

3 years ago

Which of the following best describes compounds?

pshichka [43]

I would say A because they are two or more different elements bound chemically together and can only be separated chemically.

8 0

3 years ago

Read 2 more answers

Compound b has a molecular formula of c7h16o. what is the unsaturation number (un) or double-bond equivalent (dbe)?

aksik [14]

Answer: -

Zero

Explanation: -

Double bond equivalent or level of unsaturation is the number of unsaturation present in a organic molecule. The term unsaturation may refer to a double bond or a ring system.

The double bond equivalent for an organic compound can be found out by the help of the formula

DBE = C+1 -0.5 H - 0.5 X + 0.5 N

The chemical formula of the compound B = C₇H₁₆O

So there are 7 carbons, 16 hydrogens and 1 oxygen. There is no halogen or nitrogen.

Plugging into the formula,

DBE = 7 + 1 - 0.5 x 16

= 0

Thus there is no unsaturation or double bond present in the compound B with the molecular formula C₇H₁₆O

6 0

3 years ago

What is the molar concentration (in moles/L) of a solution made with 3.744 g of Mg(NO3)2 dissolved in enough water to make 50.0

Annette [7]

Answer:

The molar concentration of a solution made with 3.744 g of Mg(NO₃)₂ dissolved in enough water to make 50.0 mL of solution is $0.5 \frac{moles}{L}$

Explanation:

Molarity or Molar Concentration is the number of moles of solute that are dissolved in a certain volume.

The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:

$molarity=\frac{number of moles}{volume}$

In this case:

Mg: 24.3 g/mole
N: 14 g/mole
O: 16 g/mole

So, the molar mass of Mg(NO₃)₂ is:

Mg(NO₃)₂= 24.3 g/mole + 2*(14 g/mole + 3*16 g/mole)= 148.3 g/mole

So, if you have 3.744 g of Mg(NO₃)₂, you can apply the following rule of three: if 148.3 grams of Mg(NO₃)₂ are present in 1 mole, 3.744 grams in how many moles are present?

$moles=\frac{3.744 grams*1mole}{148.3 grams}$

moles= 0.025

Then you have:

number of moles=0.025
volume= 50 mL= 0.05 L (being 1,000 mL= 1 L)

Replacing in the definition of molarity:

$molarity=\frac{0.025 moles}{0.05 L}$

you get:

$molarity=0.5 \frac{moles}{L}$

The molar concentration of a solution made with 3.744 g of Mg(NO₃)₂ dissolved in enough water to make 50.0 mL of solution is $0.5 \frac{moles}{L}$

6 0

3 years ago