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3 years ago

What is a chemical change

Chemistry

1 answer:

antiseptic1488 [7]3 years ago

3 0

Answer:

chimical change means when one or more new substances are formed.

Explanation:

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An analytical chemist is titrating 242.5mL of a 1.200M solution of hydrazoic acid HN3 with a 0.3400M solution of NaOH. The pKa o

Arlecino [84]

Answer:

The pH of the solution is 12.61

Explanation:

Step 1: Data given

Concentration of hydrazoic acid solution = 1.200 M

Volume of the solution = 242.5 mL = 0.2425 L

Concentration of NaOH solution = 0.3400 M

The pKa of hydrazoic acid is 4.72

Step 2: The balanced equation

NaOH + HN3 → NaN3 + H2O

Step 3: Calculate moles hydrazoic acid

Moles hydrazoic acid (HN3) = concentration * volume

Moles hydrazoic acid = 1.200 M * 0.2425 L

Moles hydrazoic acid = 0.291 moles

Step 4: Calculate moles NaOH

Moles NaOH = 0.3400 M * 1.006 L

Moles NaOH = 0.342 moles

Step 5: Determine the limiting reactant

HN3 is the limiting reactant. It will completely be consumed (0.291 moles)

NaOH is in excess. There reacts 0.291 moles. There will remain 0.342 - 0.291 = 0.051 moles NaOH

Step 6: Calculate total volume

Total volume = 242.5 mL + 1006 mL = 1248.5 mL = 1.2485 L

Step 7: Calculate concentration of NaOH

concentration NaOH = 0.051 moles / 1.2485 L

concentration NaOH = 0.0408 M

Step 8: Calculate pOH

pOH = -log [OH-] = -log(0.0408)

pOH = 1.39

Step 9: Calculate pH

pH + pOH = 14

pH = 14 - pOH

pH = 14 - 1.39

pH = 12.61

The pH of the solution is 12.61

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3 years ago

For the Heisenburg uncertainty principle, where did the 4 pi come from in the equation, which is "x times p is greater than or e

Setler [38]

That factor appears when you actually do the quite complex maths that lead to the principle; it's quantum mechanics, and it's not something that can be shown easily.

What is important to note is that this factor $\frac{1}{4\pi}$ is not important. What is important is that the uncertainty $\Delta x\Delta p_x$ is approximately of the order of $\hbar=\frac{h}{2\pi}$ , which is a characteristic value that appears in many (most) formulas dealing with quantum mechanics.

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3 years ago

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rewona [7]

Answer: How many warnings have you gotten? depending on that you could've.

Explanation:

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If you want to graphb it then you should use decmos.com

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1. Hard water has about 150 ppm CaCO3. How many grams of calcium carbonate are in

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Answer:

William Shakespeare (bapt. 26 April 1564 – 23 April 1616)[a] was an English playwright, poet, and actor, widely regarded as the greatest writer in the English language and the world's greatest dramatist.[2][3][4] He is often called England's national poet and the "Bard of Avon" (or simply "the Bard").[5][b] His extant works, including collaborations, consist of some 39 plays,[c] 154 sonnets, two long narrative poems, and a few other verses, some of uncertain authorship. His plays have been translated into every major living language and are performed more often than those of any other playwright.[7] They also continue to be studied and reinterpreted.

Shakespeare was born and raised in Stratford-upon-Avon, Warwickshire. At the age of 18, he married Anne Hathaway, with whom he had three children: Susanna and twins Hamnet and Judith. Sometime between 1585 and 1592, he began a successful career in London as an actor, writer, and part-owner of a playing company called the Lord Chamberlain's Men, later known as the

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