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3 years ago

How much Sr(OH)2 • 8 H2O (M = 265.76) is needed to

1 answer:

3 0

First, you need to find the number of moles of OH⁻ in a 250mL solution of 0.100M OH⁻. To do this, multiply 0.250L by 0.100M to get 0.025mol OH⁻. Then you use the fact that 1 mole of Sr(OH₂)·8H₂O contains 2 moles of OH⁻ which means that 0.0125mol of Sr(OH)₂·8H₂O contains 0.025mol OH⁻ (0.025/2=0.0125). Then to find the amount of Sr(OH)₂·8H₂O is needed you multiply its molar mass (265.76g/mol) by 0.0125mol to get 3.322g.
Therefore you need 3.322g of Sr(OH)₂·8H₂O.

I hope that helps. Let me know if anything is unclear.

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Need help ASAP please show your work

VikaD [51]

Answer:

q = 14049 J

Explanation:

q = m*c*(t2-t1)

q = 350 * 0.892 * (70-25) =

312.2 * 45 = 14049 J

I might be getting a little confused but I could be right.

Hope this helps!

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3 years ago

In a Lewis diagram for methane (CH4), which atom or atoms is inside, or central?

Ahat [919]

Answer:

B carbon

Explanation

Lewis structure or dot structure is an easy way to get the bonding details of atoms in a molecule. If we talk about methane molecule carbon is central atom with four electrons that are bonded to four hydrogen atoms and each bond is single covalent bond.

Please see attached figure,

Hope it helps!

7 0

2 years ago

Read 2 more answers

You find a compound composed only of element X and chlorine and you know that the compound is 13.10% X by mass. Each molecule of

8_murik_8 [283]

Answer:

Explanation:

So, the formula for the compound should be:

$XCl_{6}$

Now we assume that we have 1 mol of substance, so we can make calculations to know the molar mass of element X, as follows:

$M_{Cl}=35.45g/mol\\$

So we have that 6 moles weight 212.7g, and we can make a rule of three to know the weight of compound X:

$212.7g\rightarrow 86.9\%\\x\rightarrow 13.1\%\\\\x=\frac{212.7g*13.1}{86.9} =32.06g$

As we used 1 mol, we know that the molar mass is 32.06g/mol

So the element has a molar mass of 32.06 g/mol and an oxidation state of +6, with this information, we can assure that the element X is sulfur, so the compound is $SCl_{6}$

8 0

3 years ago

Which best describes the importance of the microscope to the development of cell theory? Microscopes color different parts of ce

aliya0001 [1]

Cells are too small to see with the naked eye.

It's pretty straight forward, use the cross-out method.

1) Microscopes MAGNIFY images, they don't color the cells. In fact, scientists have to use these chemicals to "stain" or color the cells to see them more easily through microscopes.

2) If the lenses of a microscope reduced the image of an organism to the size of a cell, you'd be seeing a very tiny human through your microscope, instead of actual cells.

3) Microscopes don't "trap" anything. In fact, scientists use plates or slides under microscopes to contain what they're studying.

8 0

3 years ago

Read 2 more answers

2. The density of helium is 1.78 X 104 g/cm. What is this<br> density in Dg/um??

Zepler [3.9K]

Answer:

$d=1.78\times 10^{-7}\ Dg/\mu m^3$