Which two statements explain how a cell's parts help it get nutrients?

A collection of coins contains 14 pennies, 16 dimes, and 7 quarters. What is the percentage of pennies in the collection?A colle

marin [14]

Answer:

=37.83783784

Explanation:

Find the total sum of all coins,

which is 37, take the number of pennies and the total of all coins put in parenthesis( 14/37) like so and than * times them by 100

you equation should look like this

(14/37)* 100= and than the answer shown above should be the one you received. I have checked this with multiple calculators, it should be accurate.

8 0

2 years ago

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Use the table to identify the phase and phase changes of the elements under the given conditions. Write the name of the substanc

OLga [1]

Answers:

1. When the temperature in a room increases from25°C to 33°C, galium changes from a solid to a liquid.

2. In a lab, methane and nitrogen are cooled from -170°C to -200°C. The methane freezes and the nitrogen condenses.

3. When gold is heated to 2,856°C it changes from a liquid to a gas

Explanations:

The melting and boiling point of the substances permit to state whether a susbstance will be solid, liquid or gas at certain conditions (temperature in this case).

Melting point: is the temperature at which a solid becomes liquid.

Boiling point is the temperature at which a liquid becomes gas.

Hence:

if the temperature is below the melting point, the substance is solid.

if the temperature is between the melting and the boiling points, the substance is liquid.

if the emperature is above the boiling point the substance is gas.

The names of the phase changes dealt with in this question are:

Condenstation: pass from gas to liquid.

Boiling (Vaporization): pass from liquid to gas

Freezing: pass from liquid to solid.

Melting (fusion): pass from solid to liquid

With that let us go through the three statements:

1. When the temperature in a room increases from25°C to 33°C,

______ changes from a solid to a liquid. Answer: galium.

You need to find in the table a substance whose melting point is between 25°C and 33°C.

This is Gallium, whose melting point is indicated to be 30°C, meaning that at 25°C it is solid and at 33°C it is liquid.

2. In a lab, methane and nitrogen are cooled from -170°C to -200°C. The methane freezes and the nitrogen _____. Answer: condenses.

Since the boling point of nitrogen is - 196°C, at -170°C nitrogen is gas.

Since, the melting point is - 210°C, at -200°C, nitrogen is liquid.

So, nitrogen condenses when it is cooled from - 170°C to - 200°C.

3. When gold is heated to 2,856°C it changes from a liquid to a ____. Answer: gas.

Since, 2856°C is the boiling point of gold, it will start fo pass from liquid to gas at this temperature.

3 0

2 years ago

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A 10.63 g sample of mo2o3(s) is converted completely to another molybdenum oxide by adding oxygen. the new oxide has a mass of 1

Roman55 [17]

MoO2 First, lookup the atomic weights of the elements involved Atomic weight molybdenum = 95.94 Atomic weight oxygen = 15.999 Now calculate the molar mass of Mo2O3 2 * 95.94 + 3 * 15.999 = 239.877 g/mol Now determine how many moles of the original Mo2O3 you had 10.63 g / 239.877 g/mol = 0.044314378 mol Determine how much oxygen was added 11.340 g - 10.63 g = 0.71 g How many moles of oxygen was added 0.71 g / 15.999 g/mol = 0.044377774 mol Looking at the number of moles of oxygen added and the number of moles of the original compound, they're the same. So 1 oxygen atom was added to each molecule. Since the formula was Mo2O3, the new formula becomes Mo2O4. But since you're looking for the empirical formula, you need to reduce it. Both 2 and 4 are evenly divisible by 2, so the empirical formula becomes MoO2

7 0

2 years ago

Why is useful to use moles to measure chemical quantities

MrRa [10]

Answer:

The mole is important because it allows chemists to work with the subatomic world with macro world units and amounts. Atoms, molecules and formula units are very small and very difficult to work with usually. However, the mole allows a chemist to work with amounts large enough to use.

Explanation:

4 0

1 year ago

Based on your observations of 1-tetradecanol when it reformed a solid after melting, does 1-tetradecanol form a crystalline or a

Nitella [24]

Answer:

It is a crystalline solid.

It is a white crystalline solid that is practically insoluble in water, soluble in diethyl ether and slightly soluble in ethanol

Explanation:

The difference between crystalline and amorphous is how this chemical compound transmits light.

When a chemical material or compound is said to be crystalline, it is the opposite of what we imagine, since its color is opaque and does not allow light to pass through it, that is why this compound, being crystalline, is opaque white. and if you want to see through it you will not see the other way since it is not "transparent".

On the other hand, amorphous chemical materials or compounds are seen through them from one side to the other, they are considered "transparent" and do not refract any color from the color range of light. That is why they are not opaque either, nor do they have a particular color like white. A clear example of an amorphous structure is glass or crystal.

6 0

2 years ago