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jenyasd209 [6]
2 years ago
11

Emission nebulae are also called ____ because they are composed of ionized hydrogen.

Chemistry
1 answer:
vodomira [7]2 years ago
8 0
H II regions. The ionized gas emits various colors of light and creates some of the most beautiful formations in the observable universe. These are slo regions where star formation is often taking plan and young stars are being formed from the remnants of older stars. 
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The empirical formula of styrene is ch; its molar mass is 104.1 g/mol. what is the molecular formula of styrene? select one:
Nuetrik [128]
The empirical formula is a formula of a compound showing the proportion of each element involved in the compounds but it does not represent the total number of atoms in the compound. It is the lowest number of ratio between the elements in the compound. In order, to determine the actual number of the atoms or the molecular formula of the compounds, we make use of the molar mass of the compound. 

<span>To determine the molecular formula, we multiply a value to the empirical formula. Then, calculate the molar mass and see whether it is equal to the one given (104.1 g/ mol). From the choices, the only valid options are b, d and e.
</span>                  molar mass
1     CH          13.02
8   C8H8      104.16
6   C6H6      78.12

Therefore the correct answer is option B.
6 0
3 years ago
Read 2 more answers
The radioisotope phosphorus-32 is used in tracers for measuring phosphorus uptake by plants. The half-life of phosphorus-32 is 1
Harman [31]

Answer:

54 days

Explanation:

We have to use the formula;

0.693/t1/2 =2.303/t log Ao/A

Where;

t1/2= half-life of phosphorus-32= 14.3 days

t= time taken for the activity to fall to 7.34% of its original value

Ao=initial activity of phosphorus-32

A= activity of phosphorus-32 after a time t

Note that;

A=0.0734Ao (the activity of the sample decreased to 7.34% of the activity of the original sample)

Substituting values;

0.693/14.3 = 2.303/t log Ao/0.0734Ao

0.693/14.3 = 2.303/t log 1/0.0734

0.693/14.3 = 2.6/t

0.048=2.6/t

t= 2.6/0.048

t= 54 days

3 0
2 years ago
How are mass and weight alike?
joja [24]
Both mass and weight are measured by using scales.
7 0
2 years ago
20. Which of the following are pure substances?
Juliette [100K]
The answer is III and V
3 0
3 years ago
In k4[fe(cn)6], how many 3d electrons does the iron atom have?
san4es73 [151]
First let's find out the oxidation number of Fe in K₄[Fe(CN)₆] compound.

The oxidation number of cation, K is +1. Hence, the total charge of the anion, [Fe(CN)₆] is -4. CN has charge has -1. There are 6 CN in anion. Let's assume the oxidation number of Fe is 'a'.

Sum of the oxidation numbers of each element  = Charge of the compound
                                                          a + 6 x (-1) = -4
                                                                     a -6 = -4
                                                                         a = +2

Hence, oxidation number of Fe in [Fe(CN)₆]⁴⁻ is +2. 

Now Fe has the atomic number as 26. Hence, number of electrons in Fe at ground state is 26. 
Electron configuration = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ 4s² = [Ar] 3d⁶ 4s²

When making Fe²⁺, Fe releases 2 electrons. Hence, the number of electrons in Fe²⁺ is 26 - 2 = 24.
Hence, the electron configuration of Fe²⁺ = 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶
                                                                      = [Ar] 3d⁶

Hence, the number of 3d electrons of Fe in K₄[Fe(CN)₆] compound is 6.
3 0
3 years ago
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