3 years ago

Please help quickly! Real answers only!

Chemistry

1 answer:

igomit [66]3 years ago

5 0

It helps compare the application of electromagnetic wavelength

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What are some ways to eliminate waste

Margaret [11]

Answer:

use following methods

Explanation:

Recycling the waste
segregation and dumping in right place
practice 4 R's
practice waste Management
reduce using undegredable waste like plastic bags

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3 years ago

True or false, The atomic number of an element is a whole number that decreases as you read across each row of

torisob [31]

Answer:

I believe it's false because the atomic number is the number of protons in the nucleus of an atom.

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3 years ago

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.

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3 years ago

Lawrencium-262 has a half-life of 4 hr. How much of a 40 mg sample remains after 12 hours?

CaHeK987 [17]

Answer:

5 mg

Explanation:

If one half life is 4 hours, then 3 half lives is 12 hours.

This means that the sample will decay to 1/8 of its original amount.

So, the answer is 40(1/8) = 5 mg.

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2 years ago

The circuit element whose purpose is to convert electrical energy into another form of energy is the _____. battery resistor fus

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The answer is Battery...

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3 years ago

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