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2 years ago

15

The half-life of radium-226 is 1,600 years. It decays into radon-222. What fraction of the original amount of radium-226 in a sa

mple will still be radium
after 8,000 years?
A.1/8
B.1/4
c.1/32
D.1/16

2 answers:

Mnenie [13.5K]2 years ago

6 0

Answer:

Your answer will be C. 1/32

vfiekz [6]2 years ago

5 0

Answer:

C. 1/32

Explanation:

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Select the correct answer. Which property is typical of a covalent compound?

Vesnalui [34]

Answer:

it is b

Explanation:

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3 years ago

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You make a solution by putting 45.6g of iron lll carbonate into 167ml of water. What is it's molarity?

ludmilkaskok [199]

1. The molar mass of Fe2(CO3)3 is 291.72 g/mol. This means that 45.6 g is equivalent to 0.156 mol. Dividing by the 0.167 L of water gives a solution of 0.936 M.
2. Multiplying (0.672 M)(0.025 L) = 0.0168 mol. The molar mass of Ni(OH)2 is 92.71 g/mol, so multiplying by 0.0168 mol = 1.56 grams. Therefore you would need to dissolved 1.56 g of Ni(OH)2 into 25 mL of water.
3. Fe2(CO3)3 + Ni(OH)2 --> Fe(OH)3 + NiCO3Balancing: Fe2(CO3)3 + 3Ni(OH)2 --> 2Fe(OH)3 + 3NiCO3The reaction quotient is:[Fe(OH)3]^2 * [NiCO3]^3 / [Fe2(CO3)3][Ni(OH)2]^3= (0.05)^2 * (1.45)^3 / (0.936)(0.672)^3= 0.0268Since this is < 1, it implies that the reactants are favored at equilibrium.

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3 years ago

Group the following electron configurations in pairs that would represent similar chemical properties at their atoms;

marishachu [46]

<u>Answer:</u> Pairs are: (a) and (d), (b) and (f), (c) and (e)

<u>Explanation:</u>

In a periodic table, elements are arranged in 18 vertical columns known as groups and 7 horizontal rows known as periods.

Elements arranged in a group show similar chemical properties because of the presence of same number of valence electrons.

Valence electrons are defined as the electrons which are present in the outermost shell of an atom. Outermost shell has the highest value of 'n' that is principal quantum number.

For the given options:

<u>For a:</u>

The given electronic configuration is: $1s^22s^22p^63s^2$

The number of valence electrons in the given configuration are 2

<u>For b:</u>

The given electronic configuration is: $1s^22s^22p^63s^3$

The number of valence electrons in the given configuration are [2 + 3] = 5

<u>For c:</u>

The given electronic configuration is: $1s^22s^22p^63s^23p^64s^23d^{10}4p^6$

The number of valence electrons in the given configuration are [2 + 6] = 8

<u>For d:</u>

The given electronic configuration is: $1s^22s^2$

The number of valence electrons in the given configuration are 2

<u>For e:</u>

The given electronic configuration is: $1s^22s^22p^6$

The number of valence electrons in the given configuration are [2 + 6] = 8

<u>For f:</u>

The given electronic configuration is: $1s^22s^22p^63s^23p^3$

The number of valence electrons in the given configuration are [2 + 3] = 5

Electronic configuration of (a) and (d) will form a pair, (b) and (f) will form a pair, (c) and (e) will form a pair and will have similar chemical properties.

Hence, the pairs are: (a) and (d), (b) and (f), (c) and (e)

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3 years ago

Which mixture is classified as a solution?

svlad2 [7]

Salt water is considered to be a solution

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3 years ago

Consider the following properties: I) The red color of rubies is due to the presence of chromium ions. II) Objects made of silve

quester [9]

Answer:

II) Objects made of silver become tarnished.

Explanation:

Physical properties are the properties which can be observed without changing identity of substance.

Chemical properties are the properties which describe how the substance changes into the different substance completely.

Boiling is an example of physical change in state of the substance. Color is also an example of physical property like boiling point and hence these are constants. The reason of the color is that the chromium ions shows certain colors as the electrons are excited due to absorption of the light. The tarnishing of the silver is an example of the chemical change which occurs due to the reaction of the silver with oxygen. This is also known as corrosion.

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3 years ago