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marysya [2.9K]
2 years ago
12

Multiple Choice Questions 1. Which of the following statement best describes an atom? A. Protons and electrons are grouped toget

her in a random pattern. B. Protons and electrons are grouped together in an alternating pattern C. A core of protons and neutrons surrounded by electrons. D. A core of electrons and neutrons surrounded by protons. 2. Table 5.10 shows the atomic mass of four stable isotopes of an element X. 119​

Chemistry
2 answers:
OverLord2011 [107]2 years ago
6 0
The answer is C. Here check out this diagram of an atom.

Arturiano [62]2 years ago
5 0

Answer:

C is Correct

Explanation:

Protons and Neutrons make up the Nucleus while Electrons surround the nucleus in circular orbits with continuous rotation.

You might be interested in
What is the empirical formula for the following molecular formula: C10H5O2
Tju [1.3M]

The empirical formula is the same as the molecular formula : C₁₀H₅O₂

<h3>Further explanation</h3>

Given

Molecular formula : C₁₀H₅O₂

Required

The empirical formula

Solution

The empirical formula (EF) is the smallest comparison of atoms of compound forming elements.  

The molecular formula (MF) is a formula that shows the number of atomic elements that make up a compound.  

(empirical formula) n = molecular formula  

<em>(EF)n=MF </em>

(EF)n = C₁₀H₅O₂

If we divide by the number of moles of Oxygen (the smallest) which is 2 then the moles of Hydrogen will be a decimal number (not whole), which is 2.5, then the empirical formula is the same as the molecular formula

4 0
3 years ago
A gaseous substance turns directly into a solid. Which term describes this change?
UkoKoshka [18]

Answer:

deposition

Explanation:

Sublmation- solid transforming into a gas, skipping the liquid stage.

eveporation- a liquid transformimg into a gas

melting- a solid transforming into a liquid

deposition- the opposite of sublimation (your anwser)

7 0
2 years ago
Read 2 more answers
The dating of geological formations is an example of a beneficial use of
Nitella [24]
The answer is (4). You may recall the term "radiometric dating," which refers to the dating of old artifacts by measuring proportions of certain radioactive isotopes they contain and making calculations based on their estimated half-lives. Geological formations are dated in this way.
3 0
2 years ago
A sample of fluorine gas has a volume of 5.63 L at 14°C and standard pressure. What will be the pressure in atm if the moles of
soldier1979 [14.2K]

With standard pressure there is a set list of values. (at STP), most common is 760torr. So whenever you see "at STP" or "at standard temperature pressure" you will use 760torr for pressure. Same thing goes with temperature, if you're not given temp and it says at STP you will use 273K.

For this problem:

You will be using the combined gas law:

(Pressure 1) x (Volume 1) / (Temp. 1) = (Pressure 2) x (Volume 2) / (Temp. 2)

(760torr) x (5.63L) / (287K) = (?) (9.21L) / (287K)

Pressure 2 = 465torr

*Hope this clarifies STP for you! :)

6 0
3 years ago
Calculate the frequency of the n=2 line in the lyman series of hydrogen
Alona [7]

Answer:

Approximately 2.47\times 10^{15}\; \rm Hz.

Explanation:

The Lyman Series of a hydrogen atom are due to electron transitions from energy levels n \ge 2 to the ground state where n = 1. In this case, the electron responsible for the line started at n = 2 and transitioned to

A hydrogen atom contains only one electron. As a result, Bohr Model provides a good estimate of that electron's energy at different levels.

In Bohr's Model, the equation for an electron at energy level n (

\displaystyle - \frac{k\, Z^2}{n^2} (note the negative sign in front of the fraction,)

where

  • k = 2.179 \times 10^{-18}\; \rm J is a constant.
  • Z is the atomic number of that atom. Z = 1 for hydrogen.
  • n is the energy level of that electron.

The electron that produced the n = 2 line was initially at the

\begin{aligned} &E_{n = 2} \cr &= -\frac{k\, Z^2}{n^2} \cr &= -\frac{2.179 \times 10^{-18} \times 1}{2^2} \cr & \approx -5.4475\times 10^{-19}\; \rm J\end{aligned}.

The electron would then transit to energy level n = 1. Its energy would become:

\begin{aligned} &E_{n = 1} \cr &= -\frac{k\, Z^2}{n^2} \cr &= -\frac{2.179 \times 10^{-18} \times 1}{1^2} \cr & \approx -2.179 \times 10^{-18} \; \rm J\end{aligned}.

The energy change would be equal to

\begin{aligned}&\text{Initial Energy} - \text{Final Energy} \cr &= E_{n = 2} - E_{n = 1} \cr &= -5.4475 \times 10^{-19} - \left(-2.179 \times 10^{-18}\right) \cr & \approx 1.63425\times 10^{-18}\; \rm J \end{aligned}.

That would be the energy of a photon in that n = 2 spectrum line. Planck constant h relates the frequency of a photon to its energy:

E = h \cdot f, where

  • E is the energy of the photon.
  • h \approx 6.62607015\times 10^{-34}\; \rm J \cdot s is the Planck constant.
  • f is the frequency of that photon.

In this case, E \approx 1.63425 \times 10^{-18}\; \rm J. Hence,

\begin{aligned} f &= \frac{E}{h} \cr &\approx \frac{1.63425\times 10^{-18}}{6.62607015\times 10^{-34}} \cr & \approx 2.47 \times 10^{15}\; \rm s^{-1}\end{aligned}.

Note that 1 \; \rm Hz = 1 \; \rm s^{-1}.

6 0
3 years ago
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