When more than one variable changes during a scientific experiment,

Which of the following is a compound? A. Sn B. CO C. H D. Mg

UkoKoshka [18]

The correct answer is: [B]: " CO " .
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<u>Note</u>: This is the only answer choice given that contains two different elements.
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3 0

3 years ago

Question 1(Multiple Choice Worth 4 points)

zubka84 [21]

<u>Answer </u>

Answer 1 : 28.9 g of CO is needed.

Answer 2 : Six moles of $H_{2}O$ over Nine moles of $O_{2}$

Answer 3 : Four over two fraction can be used for the mole ratio to determine the mass of Fe from a known mass of $Fe_{2}O_{3}$ .

Answer 4 : Mass of $O_{2}$ = (150 × 3 × 31.998) ÷ (232.29 × 1) grams

Answer 5 : 8.4 moles of sodium cyanide (NaCN) would be needed.

<u>Solution </u>

Solution 1 : Given,

Given mass of $Fe_{2}O_{3}$ = 55 g

Molar mass of $Fe_{2}O_{3}$ = 159.69 g/mole

Molar mass of CO = 28.01 g/mole

Moles of $Fe_{2}O_{3}$ = $\frac{\text{ Given mass of } Fe_{2}O_{3}}{\text{ Molar mass of } Fe_{2}O_{3}}$ = $\frac{55 g}{159.69 g/mole}$ = 0.344 moles

Balanced chemical reaction is,

$Fe_{2}O_{3}(s)+3CO(g)\rightarrow 2Fe(s)+3CO_{2}(g)$

From the given reaction, we conclude that

1 mole of $Fe_{2}O_{3}$ gives → 3 moles of CO

0.344 moles of $Fe_{2}O_{3}$ gives → 3 × 0.344 moles of CO

= 1.032 moles

Mass of CO = Number of moles of CO × Molar mass of CO

= 1.032 × 28.01

= 28.90 g

Solution 2 : The balanced chemical reaction is,

$2C_{3}H_{6}+9O_{2}\rightarrow 6CO_{2}+6H_{2}O$

From the given reaction, we conclude that the Six moles of $H_{2}O$ over Nine moles of $O_{2}$ is the correct option.

Solution 3 : The balanced chemical reaction is,

$4Fe+3O_{2}\rightarrow 2Fe_{2}O_{3}$

From the given balanced reaction, we conclude that Four over two fraction can be used for the mole ratio to determine the mass of Fe from a known mass of $Fe_{2}O_{3}$ .

Solution 4 : Given,

Given mass of $Zn(ClO_{3})_{2}$ = 150 g

Molar mass of $Zn(ClO_{3})_{2}$ = 232.29 g/mole

Molar mass of $O_{2}$ = 31.998 g/mole

Moles of $Zn(ClO_{3})_{2}$ = $\frac{\text{ Given mass of }Zn(ClO_{3})_{2} }{\text{ Molar mass of } Zn(ClO_{3})_{2}}$ = $(\frac{150\times 1}{232.29})moles$

The balanced chemical equation is,

$Zn(ClO_{3})_{2}}\rightarrow ZnCl_{2}+3O_{2}$

From the given balanced equation, we conclude that

1 mole of $Zn(ClO_{3})_{2}$ gives → 3 moles of $O_{2}$

$(\frac{150\times 1}{232.29})moles$ of $Zn(ClO_{3})_{2}$ gives → $[(\frac{150\times 1}{232.29})\times 3] moles$ of $O_{2}$

Mass of $O_{2}$ = Number of moles of $O_{2}$ × Molar mass of $O_{2}$ = $[(\frac{150\times 1}{232.29})\times 3] \times 31.998 grams$

Therefore, the mass of $O_{2}$ = (150 × 3 × 31.998) ÷ (232.29 × 1) grams

Solution 5 : Given,

Number of moles of $Na_{2}SO_{4}$ = 4.2 moles

Balanced chemical equation is,

$H_{2}SO_{4}+2NaCN\rightarrow 2HCN+Na_{2}SO_{4}$

From the given chemical reaction, we conclude that

1 mole of $Na_{2}SO_{4}$ obtained from 2 moles of NaCN

4.2 moles of $Na_{2}SO_{4}$ obtained → 2 × 4.2 moles of NaCN

Therefore,

The moles of NaCN needed = 2 × 4.2 = 8.4 moles

3 0

3 years ago

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Mechanical waves travel best through a

Maru [420]

$\huge{\color{magenta}{\fcolorbox{magenta}{black}{\huge{\color{white}{\fcolorbox{aqua}{black}{✿ᴀɴsᴡᴇʀ✿}}}}}}$

<u>vaccum</u>

3 0

2 years ago

Write a chemical equation representing the first ionization energy for lithium. use e− as the symbol for an electron.

just olya [345]

The chemical equation representing the first ionization energy for lithium is given by;

Li → Li + e-

<h2>Further Explanation; </h2><h3>Ionization energy</h3>

Ionization energy is the energy required to remove outermost electrons from the outermost energy level. Energy is required to remove an electron from an atom.
The closer an electron is to the nucleus the more energy is required, since the electron is more tightly bound to the atom thus making it more difficult to remove, hence higher ionization energy.
Ionization energy increases across the periods and decreases down the group from top to bottom.
Additionally, the ionization energy increases with subsequent removal of a second or a third electron.

<h3>First ionization energy </h3>

This is the energy required to remove the first electron from the outermost energy level of an atom.
Energy needed to remove the second electron to form a divalent cation is called the second ionization energy.

<h3>Trends in ionization energy </h3><h3>1. Down the group(top to bottom)</h3>

Ionization energy decreases down the groups in the periodic table from top to bottom.
It is because as you move down the group the number of energy levels increases making the outermost electrons get further from the nucleus reducing the strength of attraction to the nucleus.
This means less energy will be required compared to an atoms of elements at the top of the groups.

<h3>2. Across the period (left to right)</h3>

Ionization energy increases across the period from left to right.
This can be explained by an increase in nuclear energy as extra protons are added to the nucleus across the period increasing the strength of attraction of electrons to the nucleus.
Consequently, more energy is needed to remove electrons from the nucleus.

Keywords: Ionization energy, periodic table, energy levels, electrons

<h3>Learn more about</h3>

Ionization energy: brainly.com/question/1971327
Trend in ionization energy: brainly.com/question/1971327
First ionization energy: brainly.com/question/1971327

Level: High school

Subject: Chemistry

Topic: Periodic table and chemical families

Sub-topic: Ionization energy

4 0

3 years ago

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Which describes the products created from fission reactions? Question 3 options:

Ipatiy [6.2K]

<u>Answer:</u> The correct answer is option A.

<u>Explanation:</u>

Nuclear fission reactions are a type of nuclear reactions in which larger nuclei breaks apart into two or more smaller fragment releasing alpha, gamma of beta particles.

There are 3 types of particles that can be released during this process:

1. Alpha particles: These particles are released when a nuclei undergoes alpha-decay process.

$_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}\textrm{Y}+_2^4\alpha$

2. Beta particles: These particles are released when a nuclei undergoes beta-minus decay process.

$_Z^A\textrm{X}\rightarrow _{Z+1}^{A}\textrm{Y}+_{-1}^0\beta$

3. Gamma radiations: these radiations are released when an unstable nuclei gives off excess energy by a process of spontaneous electromagnetic process.

$_Z^A\textrm{X}^*\rightarrow _Z^A\textrm{X}+_0^0\gamma$

Hence, any of these particles can be released during the process of fission reaction with smaller atoms.

Therefore, the correct answer is option A.

3 0

3 years ago