49 After decaying for 48 hours, l/16 of the original mass of a radioisotope sample remains unchanged. What is the half-life of this radioisotope?(1) 3.0 h (3) 12 h(2) 9.6 h (4) 24 h

Methane and ethane demonstrate the law of definite composition and the law of multiple proportions as these both compounds have the exact atoms but in different ratios.  

As for methane, it can be seen that every methane molecule contains 4 hydrogen atoms and 1 carbon atom. Where masses of carbon and hydrogen are in ratio - 12 g C / 4 g H -- reduce to 3g C/ 1 g H .

Ethane contains 2 carbon atoms and 6 hydrogen atom and their mass ratio will be  - 24 g C / 6 g H -- reduce to 4 g C/ 1 g H .

So both ethane and methane demonstrate the law of definite composition and the law of multiple proportions.

Law of definite composition: The elements which are present in the compound is combined in the same proportion by mass.

Law of multiple proportion: When two or more compounds are formed by the combination of two elements then the mass ratio of one element is combined with the fixed mass of the other element.

In case of methane, it consist of one carbon atoms and four hydrogen atoms implies that has definite composition. In terms of mass, in methane, carbon and hydrogen atoms are combined in a definite ratio i.e. 12 g C/ 4 g H. Thus, methane has definite composition.  

Now, carbon and hydrogen combines to give a class i.e. hydrocarbon. In this case, for every constant mass of carbon the ratio of hydrogen will always reduce to 4/3 ratio for the formation of ethane (hydrocarbon). Thus, law of multiple proportion followed.

Similarly, in case of ethane, this compound also consist of exact atoms but in different ratios.

In case of ethane, it consist of two carbon atoms and six hydrogen atoms implies that has definite composition. In terms of mass, in ethane, carbon and hydrogen atoms are combined in a definite ratio i.e. 24 g C/ 6 g H. Thus, methane has definite composition.  

Now, carbon and hydrogen combines to give a class i.e. hydrocarbon. In this case, for every constant mass of carbon the ratio of hydrogen will always reduce to a specific ratio for the formation of methane (hydrocarbon). Thus, law of multiple proportion followed.

Fossilized plants and animals of the same species found on separate continents.

Geological features, such as mountain ranges, that align on matching coasts of different continents.

Answer:

10 g

Explanation:

Right from the start, just by inspecting the values given, you can say that the answer will be  

10 g

.

Now, here's what that is the case.

As you know, a substance's specific heat tells you how much heat is needed to increase the temperature of  

1 g

of that substance by  

1

∘

C

.

Water has a specific heat of approximately  

4.18

J

g

∘

C

. This tells you that in order to increase the temperature of  

1 g

of water by  

1

∘

C

, you need to provide  

4.18 J

of heat.

Now, how much heat would be required to increase the temperature of  

1 g

of water by  

10

∘

C

?

Well, you'd need  

4.18 J

to increase it by  

1

∘

C

, another  

4.18 J

to increase it by another  

1

∘

C

, and so on. This means that you'd need

4.18 J

×

10

=

41.8 J

to increase the temperature of  

1 g

of water by  

10

∘

C

.

Now look at the value given to you. If you need  

41.8 J

to increase the temperature of  

1 g

of water by  

10

∘

C

, what mass of water would require  

10

times as much heat to increase its temperature by  

10

∘

C

?

1 g

×

10

=

10 g

And that's your answer.

Mathematically, you can calculate this by using the equation

q

=

m

⋅

c

⋅

Δ

T

, where

q

- heat absorbed/lost

m

- the mass of the sample

c

- the specific heat of the substance

Δ

T

- the change in temperature, defined as final temperature minus initial temperature

Plug in your values to get

418

J

=

m

⋅

4.18

J

g

∘

C

⋅

(

20

−

10

)

∘

C

m

=

418

4.18

⋅

10

=

10 g

Answer:

The correct answer is b.

Explanation:

Alpha particles are fully ionized helium (4He) nucleus. These nucleus consist of two protons and two neutrons. They are positively charged (+2) due to the absence of electrons. It has the same mass as the He atom (6,64 * kg) or (4 uma), and the same charge (3,2 * C).

Have a nice day!

Answer:

The correct option is: (4) solubility and molecular polarity

Explanation:

Chromatography is an analytical technique which is used for the separation of various components in a given mixture.

In this process, the mixture to be separated is first dissolved in the mobile phase, which carries it through the stationary phase, thus leading to separation of the various components.

This differential separation is the result of the differential migration which is based upon the solubility and polarity of the individual components of of the given mixture.