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3 years ago

5

A sample of rock is found to contain 100 grams of a parent isotope. How many grams of the parent isotope will remain after one h

alf-life?
100
75
50
25

1 answer:

Inessa05 [86]3 years ago

4 0

50

One half-life would be
100^1/2, which would make it 50.

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I’m so confused please help on how to balance all these equations!

Arisa [49]

Answer:

Explanation:

Synthesis Reaction:

The reaction in which two or more molecules or compound combine together to form a new compound.

1. K + Cl₂ --------> KCl

Balanced equation

2 K + Cl₂ -------->2 KCl

--------------------------------------

2. Ca + F₂ --------> CaF₂

Balanced equation

Ca + F₂ --------> CaF₂

--------------------------------------

3. Ag + S --------> AgS

Balanced equation

2Ag + S --------> Ag₂S

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4. Na + I₂ --------> NaI

Balanced equation

2 Na + I₂ --------> 2 NaI

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5. Mg + O₂ --------> MgO

Balanced equation

2 Mg + O₂ --------> 2 MgO

--------------------------------------

6. H₂ + Cl₂ --------> HCl

Balanced equation

H₂ + Cl₂ --------> 2 HCl

____________________________

Decomposition reaction:

when one compound breaks down into 2 or more molecule or components.

7. Cs₂O --------> Cs + O₂

Balanced equation

2 Cs₂O --------> 4 Cs + O₂

--------------------------------------

8. H₂O --------> H₂ + O₂

Balanced equation

2 H₂O --------> 2 H₂ + O₂

--------------------------------------

9. MgBr₂ --------> Mg + Br₂

Balanced equation

MgBr₂ --------> Mg + Br₂

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10. AlCl₃ --------> Al + Cl₂

Balanced equation

2 AlCl₃ --------> 2 Al + 3 Cl₂

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11. KI --------> K + I₂

Balanced equation

2 KI --------> 2K + I₂

--------------------------------------

12. NaCl --------> Na + Cl₂

Balanced equation

2 NaCl --------> 2 Na + Cl₂

_______________________________

Combustion:

when a fuel burn in the presence of oxygen and produces carbon dioxide and water.

13. C₃H₈ + O₂ --------> CO₂ + H₂O

Balanced equation

C₃H₈ + 5 O₂ --------> 3 CO₂ + 4 H₂O

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14. C₂H₄ + O₂ --------> CO₂ + H₂O

Balanced equation

C₂H₄ + 3 O₂ --------> 2 CO₂ + 2 H₂O

7 0

4 years ago

Sodium, a group 1 element with an electron configuration of 1s22s23s1, will form a _____ ion in a chemical bond ?

GarryVolchara [31]

Sodium <u>loses</u> an electron, so it forms a <u><em>positive</em></u> ion

8 0

4 years ago

Consider the following specific heats: copper, 0.384 J/g· ◦C; lead, 0.159 J/g· ◦C; water, 4.18 J/g· ◦C; glass, 0.502 J/g· ◦C. Wh

Roman55 [17]

Answer:

The correct answer is

2. Water

Explanation:

The specific heat capacity is the amount of heat required to raise the temperature of a unit mass of a substance by one degree. It is connected to the capacity of the substance to retain heat as well as the rate at which it will cool down or heat up when exposed to a specific amount of heat loss or heat supplied. A substance with a low heat capacity such as iron will cool down or heat up more quicker than a substance with a high heat capacity such as water.

From the list of substances water has the highest heat capacity, (4.18 J/g) as such it will retain heat for the longest period of time.

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3 years ago

Why would a C-O bond have only provide 358 kJ/mol each while C=O provides 799 kJ/mol? Explain in detail.

Alina [70]

Consider the amount of energy needed to brake the bonds.

In c=o there are both a pi-bond and a sigma bond. Therefore it requires a higher energy to brake it. When considering the c-o bond there is only a single sigma bond is needed to be broken. Therefore braking is easier.

When something is easily broken they are having a weak attraction. When they harder to break they are having a stronger attraction.

Here weak attraction is having a lower energy while stronger attraction has higher energy.

Therefore c=o provides a high energy than c-o

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3 years ago

Please help me with these problems I am almost done with homework

Klio2033 [76]

4 Living organisms contain relatively large amounts of oxygen, carbon, hydrogen,nitrogen, and sulfur (these five elements are known as the bulk elements), along with sodium, magnesium, potassium, calcium,chlorine, and phosphorus (these six elements are known as macro minerals).

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