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3 years ago

Which statement is correct?

Chemistry

1 answer:

rosijanka [135]3 years ago

4 0

Answer:

B. Chemical changes produce new substances; physical changes do not.

Explanation:

Physical changes only alter appearances, while chemical changes are interactions that create new chemical formulas.

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A chemist must prepare of 800.0 ml potassium hydroxide solution with a pH of 13.00 at 25Â°.

ArbitrLikvidat [17]

Answer:

4.48 grams is the mass of potassium hydroxide that the chemist must weigh out in the second step.

Explanation:

The pH of the solution = 13.00

pH + pOH = 14

pOH = 14 - pH = 14 - 13.00 = 1.00

$pOH=-\log[OH^-]$

$1.00=-\log[OH^-]$

$[OH^-]=10^{-1.00} M=0.100 M$

$KOH(aq)\rightarrow K^+(aq)+OH^-(aq)$

$[KOH]=[OH^-]=[K^+]=0.100 M$

Molariy of the KOH = 0.100 M

Volume of the KOH solution = 800 mL= 0.800 L

1 mL = 0.001 L

Moles of KOH = n

$Molarity=\frac{Moles}{Volume(L)}$

$0.100 M=\frac{n}{0.800 L}$

n = 0.0800 mol

Mass of 0.0800 moles of KOH :

0.0800 mol × 56 g/mol = 4.48 g

4.48 grams is the mass of potassium hydroxide that the chemist must weigh out in the second step.

4 0

3 years ago

Why are metals good conductors of heat and electricity

Novay_Z [31]

Electric current is the flow of electrons in a wire. ... They are no longer firmly held by a specific atom, but instead they can move freely through the lattice of positive metal ions

7 0

3 years ago

Read 2 more answers

What process removes carbon dioxide from the ocean?

Katen [24]

Answer:

B. decay of dead marine organisms

Explanation:

When the temperature is low, carbon dioxide is captured by the oceans, and when the temperature is high, it is released by the oceans into the atmosphere. At sea, carbon dioxide feeds phytoplankton.

Most of the carbon dioxide consumed by plant plankton (phytoplankton) returns to the atmosphere when this phytoplankton dies or is consumed, but a portion is deposited in the ocean floor sediments when these small particles sink. This process is called a "biological bomb" because carbon dioxide is transported from the atmosphere to the ocean floor.

8 0

4 years ago

What is the mass in grams of 358 mL of ethylene glycol?

frez [133]

The density of ethylene glycol is: D = 1.11 g/mL
D = m / V
and V = 358 mL
m = D * V
m = 1.11 g/mL * 358 mL
m = 397.38 g
Answer:
Mass is 397.38 g.

6 0

4 years ago

Lighting a match changes ch and energy into heat.

otez555 [7]

Answer:

The answer remains the same. The total amount of energy stays the same because the 1st Law of Thermodynamics states that energy can neither be created nor destroyed, it can only change forms. So the chemical energy is just being converted into heat and light.

Explanation:

hope this helps...

7 0

3 years ago