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3 years ago

7

Cesium-137 has a half-life of 30 years. You find a sample with 3 g of cesium-137. How much cesium-137 existed in the sample 90 y

ears ago?

1 answer:

Reil [10]3 years ago

5 0

A lot of cesium is how much cesium you would get and stuff

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What wave has the longer wavelength

natima [27]

The wavelength is the distance between one crest/trough to another crest/trough. On the image, it's basically the length between each peak of the wave. You can see that the distance between peaks in wave A are much shorter than the distance between the peaks in wave B.

Thus, wave B has the longer wavelength.

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2 years ago

Lithium diisopropylamide (LDA) is used as a strong base in organic synthesis. LDA is itself prepared by an acid-base reaction be

kakasveta [241]

Explanation:

Lithium diisopropylamide (LDA) is used in many organic synthesis and is a strong base. It is prepared by the acid base reaction of N,N-diisopropylamine ( [(CH₃)₂CH]₂NH ) and butyllithium ( Li⁺⁻CH₂CH₂CH₂CH₃ ).

The equation is show below as:

[(CH₃)₂CH]₂NH + Li⁺⁻CH₂CH₂CH₂CH₃ ⇒ [(CH₃)₂CH]₂N⁻Li⁺ + CH₃CH₂CH₂CH₃

N,N-diisopropylamine ( [(CH₃)₂CH]₂NH ) is a weaker acid and hence, LDA ( [(CH₃)₂CH]₂N⁻Li⁺ ) is stronger base. (Weaker acid has stronger conjugate base)

Butyllithium ( Li⁺⁻CH₂CH₂CH₂CH₃ ) is a very strong base and hence, butane ( CH₃CH₂CH₂CH₃ ) is a very weak acid. (Strong base has weaker conjugate acid)

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3 years ago

How does the nucleus of a copper atom compared to the nucleus of a nickel atom

forsale [732]

Copper has 29 protons in the nucleus, while Nickel has 28 protons.

6 0

3 years ago

A water treatment plant receives the source water with an average Ca2+ concentration of 46.9 mg/L and Mg2+ concentration of 14.8

Veronika [31]

Answer:

42,650 kg of calcium carbonate will be produced everyday.

13,600.5 kg of magnesium hydroxide will be produced everyday.

Explanation:

Concentration of calcium ions = 46.9 mg/L

Concentration of magnesium ions = 14.8 mg/L

Volume of solution treated everyday , V= 80 million gal

= $80\times 10^6 gal=4.546\times 80\time 10^6 L=3.637\times 10^8 L$

1 gallon = 4.546 Liter

Mass of calcium ion in V = $46.9 mg/L\times 3.637\times 10^8 L$

= $1.706\times 10^{10} mg$

1 mg = 0.001 g

$1.706\times 10^{7} g$

Moles of calcium ions = $\frac{1.706\times 10^{7} g}{40 g/mol}=426,500 mol$

From 1 mole of calcium ion 1mol of carbonate is formed . then from 426,500 moles of calcium ion will form :

$\frac{1}{1}\times 426,500 mol=426,500 mol$ of calcium carbonate

Mass of 426,500 moles of calcium carbonate:

426,500 mol × 100 g/mol = 42,650,000 g = 42,650 kg

Mass of magnesium ion in V = $14.8 mg/L\times 3.637\times 10^8 L$

= $5.382\times 10^{9} mg$

= $5.382\times 10^{6} g$

Moles of magnesium ions = $\frac{5.382\times 10^{6} g}{24 g/mol}=224,250 mol$

From 1 mole of magnesium ion 1 mol of magnesium hydroxide is formed . then from 224,250 moles of magnesium ion will form :

$\frac{1}{1}\times 224,250 mol=224,250 mol$ of magnesium hydroxide

Mass of 224,250 moles of magnesium hydroxide:

224,250 mol × 58 g/mol = 13,006,500 g = 13,006.5 kg

42,650 kg of calcium carbonate will be produced everyday.

13,600.5 kg of magnesium hydroxide will be produced everyday.

3 0

3 years ago

The skull, vertebral column, and thoracic cage form the __________ skeleton.

Leokris [45]

<span>The skull, vertebral column, and thoracic cage are the main part of the axial skeleton.

So, the answer is that the skull, vertebral column, and thoraic cage form the axial skeleton.

If you look at a diagram of the axial skeleton you will see the bones of the head (skull) , the spine (vertebral column), and the rib cage (toracic cage)
</span>

8 0

3 years ago