All categories

3 years ago

Why is it that the north star is the only star in the night sky that seems to stay still

1 answer:

8 0

I think it is because it is directly about the north or south pole (I forget) so while all the other stars seem to rotate around because the Earth is rotating but the North Star is directly in the center. Don't take my word though.

You might be interested in

Acids which contain only hydrogen and a single other element are referred to as.

Pachacha [2.7K]

$\huge{\green}\fcolorbox{blue}{cyan}{\bf{\underline{\red{\color{red}Answer}}}}$

A binary acid is an acid that consists of hydrogen and one other element.

8 0

2 years ago

Write the formulas for the following

vredina [299]

The formula of the given compounds are as follows:

a. copper (II) phosphate : Cu₃(PO₄)₂

b. phosphorus trichloride : PCl₃

c. potassium sulfite : K₂SO₃

d. strontium nitride : Sr₃N₂

e. nitrous acid : HNO₂

<h3>What is the formula of a compound?</h3>

The formula of a compound represents the compound using the symbol of the component elements in the compound showing the ratio in which the atoms of the elements combine in the compound.

The formula of the given compounds are as follows:

a. copper (II) phosphate : Cu₃(PO₄)₂

b. phosphorus trichloride : PCl₃

c. potassium sulfite : K₂SO₃

d. strontium nitride : Sr₃N₂

e. nitrous acid : HNO₂

In conclusion, the formula of a compound represents the compound with symbols.

Learn more about formula of compound at: brainly.com/question/13522594

#SPJ1

6 0

1 year ago

Which one of the following statements is not true concerning 2.00 L of a 0.100 M solution of Ca3(PO4)2?

Len [333]

Answer: The correct answer is Option B.

Explanation:

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$ .......(1)

For A:

Molarity of calcium phosphate solution = 0.100 M

Volume of solution = 2.00 L

Putting values in equation 1, we get:

$0.100M=\frac{\text{Moles of }Ca_3(PO_4)_2}{2.00}\\\\\text{Moles of }Ca_3(PO_4)_2=(0.100mol/L\times 2.00L)=0.200mol$

Moles of calcium phosphate = 0.200 moles

For B:

1 mole of calcium phosphate contains 3 moles of calcium atoms, 2 moles of phosphate atoms and 8 moles of oxygen atoms.

So, 0.200 moles of calcium phosphate will contain = $(8\times 0.200)=1.6$ moles of oxygen atoms.

Moles of oxygen atoms = 1.6 moles

For C:

Molarity of calcium phosphate solution = 0.100 M

Volume of solution = 1.00 L

Putting values in equation 1, we get:

$0.100M=\frac{\text{Moles of }Ca_3(PO_4)_2}{1.00}\\\\\text{Moles of }Ca_3(PO_4)_2=(0.100mol/L\times 1.00L)=0.100mol$

Moles of calcium ions = $(0.100\times 3)=0.300$ moles

For D:

Molarity of calcium phosphate solution = 0.100 M

Volume of solution = 5.00 L

Putting values in equation 1, we get:

$0.100M=\frac{\text{Moles of }Ca_3(PO_4)_2}{5.00}\\\\\text{Moles of }Ca_3(PO_4)_2=(0.100mol/L\times 5.00L)=0.500mol$

Moles of phosphorus atoms = $(0.500\times 2)=1.00$ moles

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of atoms

Number of phosphorus atoms in 0.500 moles of calcium phosphate will be = $(1.00\times 6.022\times 10^{23})=6.022\times 10^{23}$

For E:

1 mole of calcium phosphate contains 3 moles of calcium ions and 2 moles of phosphate ions.

So, 0.200 moles of calcium phosphate will contain = $(3\times 0.200)=0.600$ moles of calcium ions

Moles of calcium ions = 0.600 moles

Hence, the correct answer is Option B.

6 0

2 years ago

The Lyman series results from excited state hydrogen atoms transiting to

Nutka1998 [239]

Answer:

I can't draw diagrams on this web site but I can do with numbers I think. So an electron is moved from n = 1 to n = 5. I'm assuming I've interpreted the problem correctly; if not you will need to make a correction. I'm assuming that you know the electron in the n = 1 state is the ground state so the 4th exited state moves it to the n = 5 level.

n = 5 4th excited state

n = 4 3rd excited state

n = 3 2nd excited state

n = 2 1st excited state

n = 1 ground state

Here are the possible spectral lines.

n = 5 to 4, n = 5 to 3, n = 5 to 2, n = 5 to 1 or 4 lines.

n = 4 to 3, 4 to 2, 4 to 1 = 3 lines

n = 3 to 2, 3 to 1 = 2 lines

n = 2 to 1 = 1 line. Add 'em up. I get 10.

b. The Lyman series is from whatever to n = 1. Count the above that end in n = 1.

c.The E for any level is -21.8E-19 Joules/n^2

To find the E for any transition (delta E) take E for upper n and subtract from the E for the lower n and that gives you delta E for the transition.

So for n = 5 to n = 1, use -Efor 5 -(-Efor 1) = + something which I'll leave for you. You could convert that to wavelength in meters with delta E = hc/wavelength. You might want to try it for the Balmer series (n ending in n = 2). I think the red line is about 650 nm.

Explanation:

8 0

2 years ago

How are the elements arranged in the modern periodic table? mastering?

SIZIF [17.4K]

Periodic table of the elements, in chemistry, the organized array of all the chemical elements in order of increasing atomic number—i.e., the total number of protons in the atomic nucleus.

6 0

3 years ago

Read 2 more answers