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LiRa [457]
3 years ago
13

A sample taken from a layer of mica in a canyon has 2.10 grams of potassium-40. A test reveals it to be 2.6 billion years old. H

ow much
potassium-40 was in the sample originally if the half-life of potassium-40 is 1.3 billion years?
A. 4.20
B. 8.40 g
c. 12.6 g
D. 16.8 g
E. 25.2 g
Chemistry
2 answers:
Katyanochek1 [597]3 years ago
8 0

Answer:

The correct answer is b

Explanation:

Arte-miy333 [17]3 years ago
4 0

Answer:

Correct Answer is (B)

Explanation:

Got it right on plato Chemistry Post test

<em>Hope I helped you out :)</em>

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A cube has sides of 11.4 cm. What is its volume?
9966 [12]
It is A) 1,482 cm3  ..............
4 0
4 years ago
Marcus measured the masses and volumes of samples of four different substances, and he calculated their densities. The table sho
Zina [86]

<u>Given:</u>

Calculated density values-

Aluminum = 2.7 g/cm3

Copper = 9.0 g/cm3

Iron = 7.9 g/cm3

Titanium = 4.8 g/cm3

Unknown sample mass = 9.5 g

Sample volume = 2.1 cm3

<u>To determine:</u>

The identity of the unknown sample

<u>Explanation:</u>

'Density' is a physical parameter which can be used to identify the nature of the unknown substance.

Density = Mass/Volume

For the unknown sample

Density = 9.5 g/2.1 cm3 = 4.52 g/cm3

This matches closely with the calculated density of titanium

Ans: The unknown substance is made of titanium

4 0
3 years ago
Which process would require the least amount of energy?
Aleksandr [31]
Answer:<span> a) the process for the first ionization energy
</span>
<span>Every time you take a electron you're requiring more and more energy. Expelling the first one will require less energy than expelling the second and the second will require less than the third, and so on.
When you take the first one, the atom becomes positive and with that the negative forces of the electron will be more attracted to the positive charge. The more electrons that are lost, the more positive this ion will become, causing it to be more difficult to separate the electrons from the atom.
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8 0
3 years ago
Metals posses varying reduction potentials. Iron can reduce Cu+2 (aq) to copper metal. Silver can reduce Au+ (aq) to gold metal.
natta225 [31]

<u>Answer:</u> The true statement is iron can reduce Au^+(aq) to gold metal

<u>Explanation:</u>

Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

A+BC\rightarrow AC+B

Metal A is more reactive than metal B.

We are given:

Iron can reduce copper, silver can reduce gold, sodium can reduce iron and copper can reduce silver metal.

The increasing order of reactivity thus follows:

Au

where, sodium is most reactive and gold is least reactive

For the given options:

<u>Option 1:</u>  Copper cannot easily reduce sodium ion to sodium metal because it is less reactive.

Cu(s)+Na^+(aq.)\rightarrow \text{ No reaction}

<u>Option 2:</u>  Iron cant easily reduce gold ion to gold metal because it is more reactive.

Fe(s)+3Au^+(aq.)\rightarrow Fe^{3+}(aq.)+3Au(s)

<u>Option 3:</u>  Silver cannot easily reduce iron ion to iron metal because it is less reactive.

Ag(s)+Fe^{3+}(aq.)\rightarrow \text{ No reaction}

Hence, the true statement is iron can reduce Au^+(aq) to gold metal

7 0
3 years ago
A stock solution containing Mn2 ions was prepared by dissolving 1.269 g pure manganese metal in nitric acid and diluting to a fi
SOVA2 [1]

Answer:

B.

Explanation:

Hope this helpssss

<33

8 0
3 years ago
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