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2 years ago

Can someone help me please?

Chemistry

1 answer:

mafiozo [28]2 years ago

7 0

Answer:

3 moles Al2O3

Explanation:

See attached image.

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starting with the idea of isostasy and ending with plate tectonics, explain how scientists understanding of the earth's crust ha

anzhelika [568]

Answer:

Isostasy controls the regional elevations of continents and ocean floors in accordance with the densities of their underlying rocks. ... The concept of isostasy played an important role in the development of the theory of plate tectonics.

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3 years ago

Does the following compound contain a polyatomic ion? Na2SO4 Yes No

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3 years ago

Upon heating a copper sample will expand, leading to a lower density? A) True B) False

Leona [35]

Answer;

The above statement is true

upon heating a copper sample will expand, leading to a lower density

Explanation;

-The density of solids decreased with increase in temperature and vice versa. The increase in temperature causes the volume of the solid to increase which as a result decreases the density as Density=Mass/Volume. The temperature of a body is the average kinetic energy of the molecules present in it.

In other words; The temperature of a body is the average kinetic energy of the molecules present in it. Therefore; when heat is supplied ( or temperature is increased) the average kinetic energy increases which increases the volume and thus density decreases.

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3 years ago

A. True b. False a chemical species is either an acid or a base, it cannot function as both

ivann1987 [24]

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3 years ago

What is the molarity of a solution in which 250 grams of NaCl are dissolved in 2.9 L of water?

Maksim231197 [3]

Answer:

About 1.48 M.

Explanation:

The formula for molarity is mol/L.

So firstly, you must find the amount of moles in 250 grams of NaCl.

I do this by using stoichiometry. First, I find how nany grams are in a single mole of NaCl. This is around 58.44 grams/mole. Now that I know this, I can now use a stoich table. (250 g NaCl * 1 mol NaCl / 58.44 g NaCl). I plug this into my calculator.

I get that 250 grams of NaCl is equal to about 4.28 moles.

Now I just plug into the formula!

4.28 moles/2.9 L = about 1.48

I've attached a picture of my personal notes below which shows work I have done in similar equations.

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2 years ago