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adelina 88 [10]
3 years ago
12

What is a tough, rigid, outer covering that protects some cells and gives them shape?

Chemistry
1 answer:
jeyben [28]3 years ago
7 0
It iscalled the "cell wall"
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A weather system moving through the American Midwest produced rain with an average pH of 5.02. By the time the system reached Ne
bulgar [2K]

Answer:

The rain falling in New England is 2.29 times more acidic than the one in the American Midwest.

Explanation:

The acidity of a solution depends on the concentration of H⁺ ions ([H⁺]). We can calculate this concentration from the pH using the following expression.

pH = -log ([H⁺])

American Midwest

pH = -log ([H⁺])

5.02 = -log ([H⁺])

[H⁺] = antilog (-5.02) = 9.55 × 10⁻⁶ M

New England

pH = -log ([H⁺])

4.66 = -log ([H⁺])

[H⁺] = antilog (-4.66) = 2.19 × 10⁻⁵ M

The ratio of concentrations is:

\frac{2.19 \times 10^{-5} M  }{9.55 \times 10^{-6} M} =2.29

The rain falling in New England is 2.29 times more acidic than the one in the American Midwest.

4 0
3 years ago
2.0 L of oxygen gas and 8.0 L of nitrogen gas at STP are mixed together. The gaseous mixture is compressed to occupy 2.0 L at 29
otez555 [7]

Answer:

5.5 atm

Explanation:

Step 1: Calculate the moles in 2.0 L of oxygen at STP

At STP, 1 mole of an ideal gas occupies 22.4 L.

2.0 L × 1 mol/22.4 L = 0.089 mol

Step 2: Calculate the moles in 8.0 L of nitrogen at STP

At STP, 1 mole of an ideal gas occupies 22.4 L.

8.0 L × 1 mol/22.4 L = 0.36 mol

Step 3: Calculate the total number of moles of the mixture

n = 0.089 mol + 0.36 mol = 0.45 mol

Step 4: Calculate the pressure exerted by the mixture

We will use the ideal gas equation.

P × V = n × R × T

P = n × R × T / V

P = 0.45 mol × (0.0821 atm.L/mol.K) × 298 K / 2.0 L = 5.5 atm

3 0
3 years ago
I have a mass of 30 grams and a volume of 60 cm3 what is the density
Nesterboy [21]
I think it's 534 grams per cubic centimetre
7 0
3 years ago
They are substances that produce ions when they dissolve in water.
stira [4]

Electrolytes are substances that produce ions when they dissolve in water.

What are electrolytes?

When some substances are dissolved in water, they undergo physical or chemical changes, creating ions in solution. These substances form an important class of compounds called electrolytes. Substances that do not release ions when dissolved are called non-electrolytes. A substance is said to be a strong electrolyte if the physical or chemical process that produces ions is inherently 100% efficient (all dissolved compounds produce ions). A solute is said to be a weak electrolyte if only a relatively small portion of the solute undergoes ion production processes.

By measuring the electrical conductivity of aqueous solutions containing substances, substances can be identified as strong, weak, or non-electrolyte. To conduct electricity, a substance must contain free-moving charged species. The best known is the conduction of electricity through metal wires. In this case, the mobile charged unit is the electron.

Therefore, Electrolytes are substances that produce ions when they dissolve in water.

To know more about electrolyte, visit:

brainly.com/question/17089766

#SPJ4

7 0
1 year ago
A teacher uses a bow and arrow to demonstrate accuracy and precision. She shoots several arrows, aiming at the exact center of t
RUDIKE [14]

Answer:Doing your momveryhardrn

Explanation:

She is visciously suckingmynuts

5 0
3 years ago
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