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3 years ago

Design a course of action for the development of a building project in

Chemistry

2 answers:

bixtya [17]3 years ago

7 0

Answer:

A, B & C form the vertices of a triangle.

∠ CAB = 90°, ∠ ABC = 73° and AB = 9.4.

Calculate the length of BC rounded to 3 SF

IrinaK [193]3 years ago

7 0

We need to build wildlife corridors for the prevention of road accidents.

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Choose the statement that does not apply to chemical reactions

n200080 [17]

Answer:

I think the answer to the question is c

4 0

3 years ago

Which of the following best helps to why the value of Delta H degree for the CaF_2 in water in positive? A. CaF_2(s) is insolubl

FromTheMoon [43]

Answer: Option (C) is the correct answer.

Explanation:

A positive value of enthalpy or $\Delta H$ means that energy is being absorbed from the surrounding. As $CaF_{2}$ has strong ionic bonding between both calcium and fluorine atoms. So, to break their bond we need to provide energy to it.

So, when $CaF_{2}$ is dissolved in warm water then warm water molecules will bombard with the stable bond of $CaF_{2}$ . As a result, the energy will transfer from water to the bond in order to break it. And, due to loss in internal energy then there will be consequent lowering of temperature.

When this bond is broken down then the atoms will separates into gaseous ions and these ions will be then surrounded by the water molecules. As ithe bond between $CaF_{2}$ is very strong hence, its lattice energy will be very high.

Thus, we can conclude that the statement $Ca^{2+}$ ions have very strong interactions with $F^{-}$ ions in the crystal lattice, best helps to why the value of $\Delta H$ degree for the $CaF_{2}$ in water in positive.

7 0

3 years ago

The following are the main steps in the generation of the action potential.1. Sodium channels are inactivated2. Voltage gated po

Eduardwww [97]

Answer:

E) 4,6,7,1,2,3,5

Explanation:

The correct sequence of events is as follows.
A grated depolarization brings an area of excitable membrane to a threshold.
Sodium channels are activated and open, allowing positively-charged sodium ions to pass through.
The sodium ions then enter the cell, and depolarization of the negatively-charged cell membrane is initiated.
Sodium channels are first inactivated.
The voltage-gated potassium channels then open, allowing for potassium ions to move out of the cell, initiating repolarization.
Sodium channels then regain their normal properties allowing the sodium ions to pass through and making the cell membrane repolarized again.
The cell membrane will reach its resting membrane potential again.
Afterward, a temporary hyperpolarization occurs.

6 0

3 years ago

Read 2 more answers

Help me on this question

aniked [119]

Answer:

Explanation:

That's almost the exact definition of an ecosystem.

3 0

3 years ago

Read 2 more answers

Be sure to answer all parts. A 0.365−mol sample of HX is dissolved in enough H2O to form 835.0 mL of solution. If the pH of the

Marta_Voda [28]

Answer:

The Ka is 9.11 *10^-8

Explanation:

Step 1: Data given

Moles of HX = 0.365

Volume of the solution = 835.0 mL = 0.835 L

pH of the solution = 3.70

Step 2: Calculate molarity of HX

Molarity HX = moles HX / volume solution

Molarity HX = 0.365 mol / 0.835 L

Molarity HX = 0.437 M

Step 3: ICE-chart

[H+] = [H3O+] = 10^-3.70 = 1.995 *10^-4

Initial concentration of HX = 0.437 M

Initial concentration of X- and H3O+ = 0M

Since the mole ratio is 1:1; there will react x M

The concentration at the equilibrium is:

[HX] = (0.437 - x)M

[X-] = x M

[H3O+] = 1.995*10^-4 M

Since 0+x = 1.995*10^-4 ⇒ x=1.995*10^-4

[HX] = 0.437 - 1.995*10^-4 ≈ 0.437 M

[X-] = x = 1.995*10^-4 M

Step 4: Calculate Ka

Ka = [X-]*[H3O+] / [HX]

Ka = ((1.995*10^-4)²)/ 0.437

Ka = 9.11 *10^-8

The Ka is 9.11 *10^-8

4 0

3 years ago