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3 years ago

Can someone help me on number 7

Chemistry

1 answer:

Artist 52 [7]3 years ago

3 0

The answer is "C" because all isotopes have a different mass number. The number of protons does not change. The mass of electrons is negligible. Thus, the number of neutrons changes.

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Date

expeople1 [14]

The question is confusing and all the answers are not there but it is B C and D

7 0

2 years ago

You will be using the observations given in the scenarios i - vi below to determine which of the following is true for G (a - c)

WITCHER [35]

Answer:

A spontaneous reaction is taking place in a flask. When you touch the flask, it feels cold and gets colder as the reaction progresses........(c,f,g)

A spontaneous reaction is taking place in a flask as evidenced by the formation of gas bubbles. When you touch the flask, it feels hot and gets hotter as the reaction progresses.... (c,d,h)

A spontaneous reaction is taking place in a flask. When you touch the flask, it feels hot and gets hotter as the reaction progresses....(c,f,h)

A spontaneous reaction is taking place in a flask. You notice the formation of gas bubbles intensifies as the reaction progresses....(c,d,I)

A solid in a closed flask begins to melt. (You can consider this a phase change.)....(b,d,g)

A liquid begins to appear on the inside of a closed flask. At first glance before the liquid began to appear, you might have thought the flask was empty. (You can consider this a phase change.)....(a,e,h)

Explanation:

Now it is necessary here to state the equation for ∆G

∆G= ∆H-T∆S

The values of ∆G depends on the relative values of ∆H, T and ∆S.

When heat is evolved by a system, ∆H is negative, when heat is absorbed by a system, ∆H is positive.

When gases are evolved, ∆S is positive, when gases turn to liquids or solids ∆S is negative.

Let us also recall that, for the melting process ∆S positive ( solid changes to liquid), ∆H is positive(energy is absorbed) and T increases( the substance is heated). Hence ∆G is negative

For the condensation process; ∆H is negative (heat is evolved), ∆S is negative (gas changes to liquid) and T is decreased hence ∆G is positive.

5 0

3 years ago

What is the full meaning of DR.HERC.

n200080 [17]

Answer:

It is

D- DEFINE the problem

R-RESEARCH on the problem

H- Carry out a HYPOTHESIS

E- carry out an EXPERIMENT.

R-Analyse the RESULT

C-summarise the CONCLUSION.

Explanation:

Hope it helps.

5 0

3 years ago

A hypothetical element has an atomic weight of 48.68 amu. It consists of three isotopes having masses of 47.00 amu, 48.00 amu, a

Morgarella [4.7K]

Answer : The percent abundance of the heaviest isotope is, 78 %

Explanation :

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$

As we are given that,

Average atomic mass = 48.68 amu

Mass of heaviest-weight isotope = 49.00 amu

Let the percentage abundance of heaviest-weight isotope = x %

Fractional abundance of heaviest-weight isotope = $\frac{x}{100}$

Mass of lightest-weight isotope = 47.00 amu

Percentage abundance of lightest-weight isotope = 10 %

Fractional abundance of lightest-weight isotope = $\frac{10}{100}$

Mass of middle-weight isotope = 48.00 amu

Percentage abundance of middle-weight isotope = [100 - (x + 10)] % = (90 - x) %

Fractional abundance of middle-weight isotope = $\frac{(90-x)}{100}$

Now put all the given values in above formula, we get:

$48.68=[(47.0\times \frac{10}{100})+(48.0\times \frac{(90-x)}{100})+(49.0\times \frac{x}{100})]$

$x=78\%$

Therefore, the percent abundance of the heaviest isotope is, 78 %

5 0

3 years ago

Read 2 more answers

Which of the following polyatomic ions will form an ionic compound with two sodium ions? CO32− HCO31− NO21− NO31−

BaLLatris [955]

Answer:

CO32−

Explanation:

We have to consider the valencies of the polyatomic ions involved. Recall that it is only a polyatomic ion with a valency of -2 that can form a compound which requires two sodium ions.

When we look closely at the options, we will realize that among all the options, only CO32− has a valency of -2, hence it must be the required answer. In order to be double sure, we put down the ionic reaction equation as follows;

2Na^+(aq) + CO3^2-(aq) ---------> Na2CO3(aq)

8 0

3 years ago