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2 years ago

PLEASE HELP

Chemistry

2 answers:

Amiraneli [1.4K]2 years ago

7 0

Answer:

A. Melting point

Explanation:

Isotopes have the same atomic number hence the same number of electrons which causes them to have the same chemical properties. But isotopes have different number of neutrons which causes them to have different mass numbers. The difference in mass numbers causes isotopes to have different physical properties. Heavier isotopes have a higher mass numbers than lighter isotopes because of which they have a higher melting point, boiling point etc.

Deffense [45]2 years ago

3 0

The answer is A. Isotopes only differ in the number of neutrons in the nucleus of their atoms. Otherwise, all other subatomic particles are the same. The isotope with the more neutrons in its nucleus is therefore, heavier (have higher mass number). They share the same chemical properties but have slight physical differences such as boiling points with the heavier element having a slightly higher boiling point that the lighter element.

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katrin2010 [14]

Answers:

Question 1:

The diagram for gallium will have flat, horizontal lines at 30 and 2204 °C.

Questoin 2:

The diagram for methane will have a diagonal line representing the liquid phase between -183°C and -162°C.

Question 3:

For gold, the boiling point corresponds to the y-value at 2856 °C of the top horizontal line

Question 4.

For nitrogen, the line at -210°C will be flat, which represents the change from a solid to a liquid

Explanations:

Question 1:

The diagram for gallium will have flat, horizontal lines at 30 and 2204 °C.

The table shows that the melting point of gallium is 30°C and its boiling point is 2204°C.

Melting point is the temperature at which the substace changes its state from solid to liquid. During that change, the temperature of the substance does not change, because the heat supplied is used to accomplish the phase change. So, the temperature is constant and that means that portion of the diagram is flat.

The same is valid during boiling: the temperature remains constant while the substance is passing from liquid to gas at the boiling point.

Questoin 2:

The diagram for methane will have a diagonal line representing the liquid phase between -183°C and -162°C.

Between the melting (-183°C) and boiling (-162°C) points of methane, its temperature will increase more or less linearly, which is represented with a diagonal (slant) line between those points. During this interval the heat is used to increase the temperature and no phase of change happens.

Question 3:

For gold, the boiling point corresponds to the y-value at 2856 °C of the top horizontal line

The table shows that the boiling point of gold is 2,856°C.

In a temperature-vs.-time diagram the temperature is represented on the vertical axis (y-value) and the time is represented on the horizontal axis.

Since, the temperature of the substance does not change during boiling, the line during the time that this change of phase is happening is flat. And since this temperatue is higher than the melting temperature, this is the top horizontal line in the diagram.

Question 4.

For nitrogen, the line at -210°C will be flat, which represents the change from a solid to a liquid

The table shows that the melting point of nitrogen is -210°C, that means that the temperature will remain constant at -210°C while the substance is absorbing heat to pass from solid to liquid.

In conclusion, you must remember that all the phase changes, melting (from solid to liquid), freezing (from liquid to solid), boilng (from liquid to gas), and condensing (from gas to liquid) happens at constant temperature, and so the temperature - vs. - time diagrams show flat lines (constant y-values) during those intervals of time.

4 0

2 years ago

Read 2 more answers

Describe in your own words, in terms of particle movement and energy, what occurs when a liquid is cooled to its freezing point.

IRINA_888 [86]

Liquids have free and fast moving particles. Liquids do not take a specific shape unless they are enclosed such as in a bottle. Anyway, since they are free flowing when they freeze, their movement becomes very slow. Eventually the particles will not have room to move as they used to and will be held in one place. The particles are still moving but they are only shaking or vibrating in the same place. You can't even tell this movement is happening, and that is what happens when liquid freezes.

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3 years ago

Who created the planetary model of the atom?

shtirl [24]

The answer is Rutherford.

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2 years ago

Alkaline batteries are non-rechargeable. Why do alkaline batteries eventually stop working?

scoray [572]

Answer:

Alkaline batteries stop working when all of the manganese dioxide has been converted.

Explanation: Hope it helps you :)))

Have a good day

4 0

2 years ago

Two aircraft rivets, one iron and the other copper, are placed in a calorimeter that has an initial temperature of 20.°C. The da

Igoryamba

The heat will flow from Cu to Fe because Cu has higher temperature and has lower peak value .

Given ,

two aircraft rivets , one iron and the other copper , are placed in a calorimeter .

the initial temp of the calorimeter is 20 degC .

mass of iron = 30 g

initial temp of iron = 0 degC

Mass of copper = 20 g

initial temp of copper = 100 degC

Here copper has higher temp ,thus heat flow from Cu to Fe .

Heat flow is the movement of heat from higher temperature to lower temperature .

<h3>What is calorimeter ?</h3>

It is an object used for measuring the heat flow , heat capacity of a chemical reaction as well as the physical changes .

Learn more about calorimeter here :

brainly.com/question/1407669

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1 year ago