A student-made sample of sodium carbonate weighing 0.169g that generates 37.6 mL of CO2 gas when treated with sulfuric acid. The atmospheric pressure in the lab is 731.8 mm Hg and the temp. is 21.3-degree Celsius.

A. What is the partial pressure of CO2 gas generated from the sample in mm Hg? In atm?
B. How many moles of CO2 gas are produced?
C. How many moles of pure Na2CO3 were there in the sample?
D. How much was pure Na2CO3 there in the sample, in grams?
E. What was the percent of pure Na2CO3 in the sample?

Answer:

C

Explanation:

C) All elements, including those in our body, that are heavier than hydrogen are produced by fusion at the center of stars. Explosions of these stars then lead to the creation of planets and organisms.

Fission occurs at the star's core to create all elements heavier than hydrogen, including those found in human body. The subsequent explosions of these stars and it dust result in the formation of planets and life.

Stars are massive objects in the universe with shining light and are grouped to any galaxy by the force of gravitation. Sun is a star who provide energy for us.

There are many more elements in each star which are formed through fusion such as hydrogen and helium in sun. Stars are thus the source of nuclear fusion.

Each stars have a definite life time and after that it will die by explosion and this result in a huge dust particles which are then contributing to the formation of other planets and gaseous atmosphere.

By fission takes place in the starts other elements are generated to form a stable atmosphere and that's why the musical group says that everything including them are from stardust and the statement is true.

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A) They all have similar chemical properties.

Answer: The energy of the photon having the given wavelength is [tex]2.96\times 10^{-19}J[/tex]

Explanation:

We are given:

Wavelength of microwave = [tex]670.8nm=670.8\times 10^{-9}m[/tex]    (Conversion factor:  [tex]1m=10^9nm[/tex]  )

To calculate the energy of one photon, we use Planck's equation, which is:

[tex]E=\frac{hc}{\lambda}[/tex]

where,

h = Planck's constant = [tex]6.625\times 10^{-34}J.s[/tex]

c = speed of light = [tex]3\times 10^8m/s[/tex]

[tex]\lambda[/tex] = wavelength = [tex]670.8\times 10^{-9}m[/tex]

Putting values in above equation, we get:

[tex]E=\frac{6.625\times 10^{-34}J.s\times 3\times 10^8m/s}{670.8\times 10^{-9}m}\\\\E=2.96\times 10^{-19}J[/tex]

Hence, the energy of the photon having the given wavelength is [tex]2.96\times 10^{-19}J[/tex]

Answer:

Principal energy level, sublevel, orbital, electron.  A table relating these classifications is attached.

Given:

Mass of water = 50 g

Temperature of cold water Tc= 0 C

Temperature of hot water Th= 100 C

To determine:

Final temperature Tf of water

Explanation:

Heat (Q) absorbed or evolved by a substance is given as-

Q = mc(Tf-Ti)

m = mass

c = specific heat

Tf and Ti are the final and initial temperatures

In this case:

Heat lost by hot water = Heat gained by cold water

-mc(Tf - 100 ) = mc(Tf-0)

-Tf + 100 = Tf

2Tf = 100, i.e. Tf = 50 C

Ans: the final temperature is 50 C

LiBr does not represent a molecular compound; it is an ionic compound because it is made up of lithium (metal) and bromine (nonmetal).

The student is inquiring about which of the provided options does not represent a molecular compound. Molecular compounds, also known as covalent compounds, are formed when nonmetal atoms share electrons to form discrete molecules with covalent bonds. Examples include water (H₂O) and carbon dioxide (CO₂). On the other hand, ionic compounds like sodium chloride (NaCl) are formed from the electrostatic attraction between cations and anions, which result from the transfer of electrons from metal to nonmetal atoms. Here, the substance that does not represent a molecular compound is LiBr, as it is an ionic compound composed of lithium (a metal) and bromine (a nonmetal). The formulas for molecular compounds generally display the number of each type of atom in a molecule, whereas the formula for an ionic compound represents the relative number of ions rather than discrete molecules.

The given for the problem:

100 cm^3 butane

Get first the molecular formula of butane and it is C4H10

To solution for the problem is:

2 C4H10 + 13 O2 = 8 CO2 + 10 H2O
n = V/22.4

n (C4H10) = 0.1/22.4 = 0.0047 mol

n (CO2) = 4 · n (C4H10) = 4 · 0.0047 = 0.018 mol

Burning 100 cm³ of butane in excess oxygen at STP produces 0.4 liters of carbon dioxide, as calculated through the stoichiometry of the balanced combustion reaction of butane.

When butane (C₄H₁₀) is burned in excess oxygen, the combustion reaction can be represented by the balanced equation:

2 C₄H₁₀(g) + 13 O₂(g) → 8 CO₂(g) + 10 H₂O(g)

The balanced equation shows that 2 moles of butane produce 8 moles of carbon dioxide (CO₂). At standard temperature and pressure (STP), 1 mole of any gas occupies 22.4 L. Therefore, for every 2 moles (2 × 22.4 L) of butane, 8 moles (8 × 22.4 L) of CO₂ are produced. If we burn 100 cm³ (which is equivalent to 0.1 L) of butane, we need to determine how many moles this quantity represents and then calculate the corresponding volume of CO₂ produced.

First, we calculate the moles of butane:

0.1 L butane × (1 mole butane / 22.4 L) = 0.00446 moles butane

Using the stoichiometry of the reaction, the moles of CO₂ produced are 4 times the moles of butane:

0.00446 moles butane × (4 moles CO₂ / 1 mole butane) = 0.01784 moles CO₂

Now, we convert the moles of CO₂ to volume at STP:

0.01784 moles CO₂ × (22.4 L / 1 mole CO₂) = 0.4 L CO₂

Therefore, 100 cm³ of butane will produce 0.4 liters of carbon dioxide at STP when burned in excess oxygen.

Elemental sulfur actually has 16 electrons with a neutral charge. 
The most common sulfur ion that is formed is the sulfide ion which has a negative 2 charge.

Answer:

Connexus D,B,B,A,A

Explanation:

Enzymes speed up chemical reactions by decreasing the energy needed for the reaction to occur and by providing a specific location (the active site) where the reaction can take place more easily.

Enzymes are proteins that act as biological catalysts, meaning they speed up chemical reactions that take place within the cells of organisms. They do this by reducing the energy of activation (Ea) necessary for the reaction to take place. The energy of activation is the minimum amount of energy that reactants must have to undergo a chemical reaction. By reducing the Ea, an enzyme essentially 'lowers the bar' for the reaction to happen, allowing it to proceed faster.

The reactants in the reaction that an enzyme catalyzes, also known as the substrate, bind to a specific part of the enzyme called the active site. The enzyme and substrate fit together in a manner often compared to a 'lock and key'. Once the substrate is bound to the active site, the enzyme can facilitate the reaction, converting substrate to product and then releasing the product.

To summarize, enzymes increase the rate of chemical reactions by reducing the energy of activation and by providing a suitable environment for the reaction to occur at the enzyme's active site.

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the answer is just 2 and 5

Explanation:

Butane is a four member carbon chain.

The properties of butane are as follows.

           [tex]2C_{4}H_{10} + 13O_{2}(g) \rightarrow 8CO_{2}(g) + 10H_{2}O(aq)[/tex]

Butane has weak dispersion force and water has strong hydrogen bonding.  The weak dispersion force is unable to break the hydrogen bonding hence, butane does not dissolve in water.

Thus, we can conclude that the chemical properties butane burns readily in air and does not react with water are true out of the given list of options.

Answer:

The mass we will get from AgCl is 0.839g

Explanation:

Hello!

Let's solve this!

The reaction is:

2AgC2H3O2 + MgCl2 ---> 2AgCl + Mg (C2H3O2) 2

The data we have are:

V1 = 75mL * (1L / 1000L) = 0.075L

M1 = 0.078M

V2 = 55mL * (1L / 1000mL) = 0.055L

M2 = 0.109M

The molarity formula is

M = mol / V

We calculate the moles of each compound:

molAgC2H3O2 = 0.075L * 0.078mol / L = 0.00585mol

molMgCl = 0.055L * 0.109M = 0.005995

We calculate the compound that is in excess, and then use the limiting reagent to calculate the amount of product we will obtain.

Since there are two Cl in MgCl2, this means that we have 0.01199 mol to produce the product, but we will only use 0.00585 mol which is the amount we have of AgC2H3O2. So MgCl is the excess reagent.

Then:

AgCl mass = 0.00585mol * (2mol AgCl / 2molAgC2H3O2) * (143.34g AgCl / 1mo AgCl) = 0.839gAgCl

The mass we will get from AgCl is 0.839g

0.839 g of AgCl is formed.

Given a reaction between:

Question:

What mass, in g, of AgCl is formed?

The Process:

Step-1:

Let us find the mole numbers of both reagents:

[tex]\boxed{ \ Concentration \ (M) = \frac{moles \ (n)}{volume \ (V)} \ } \rightarrow \boxed{ \ n = MV \ }[/tex]

AgC₂H₃O₂ → 0.078 x 0.075 = 5.85 mmol

MgCl₂ → 0.109 x 0.055 = 5.995 mmol

Step-2:

The equation for the reaction is

[tex]\boxed{ \ 2 AgC_2H_3O_2_{(aq)} + MgCl_2_{(aq)} \rightarrow 2 AgCl_{(s)} + Mg(C_2H_3O_2)_2_{(aq)} \ }[/tex]

According to the equation, 2 mol of AgC₂H₃O₂ react with 1 mol of AgCl.

Let us check which substances will be a limiting reagent.

AgC₂H₃O₂ → [tex]\boxed{ \ \frac{5.85}{2} = 2.925 \ }[/tex]

MgCl₂ → [tex]\boxed{ \ \frac{5.995}{1} = 5.995 \ }[/tex]

AgC₂H₃O₂ is the limiting reagent because the test results are the smallest.

Step-3:

As AgC₂H₃O₂ is the limiting reagent, the amount of AgCl produced will be determined by the amount of AgC₂H₃O₂. Since the proportion between the mole numbers of AgC₂H₃O₂ and AgCl is one to one, their mole numbers will be equal:

[tex]\boxed{ \ The \ mole \ of AgCl = \frac{1}{1} \times the \ mole \ of \ AgC_2H_3O_2 \ }[/tex]

So the amount of AgCl is 5.85 moles.

Step-4:

Prepare the molar mass of AgCl.

Mr = 108 + 35.5 = 143.5 g/mol

Let us find out how many mass, in g, of AgCl is formed.

[tex]\boxed{ \ mol \ (n) = \frac{mass \ (g)}{molar \ mass \ (Mr)} \ } \rightarrow \boxed{ \ g = n \times Mr \ }[/tex]

Mass = 5.85 mmol x 143.5 g/mol

Mass = 839.475 mg ≈ 0.839 g.

Thus the amount of AgCl is formed is 0.839 g.

Final answer:

The dissolution of ammonium nitrate in water is driven by an increase in entropy, despite it being an endothermic process. The decrease in temperature indicates energy is absorbed, but the dissolution still occurs spontaneously due to the significant increase in disorder in the system. So the correct option is C.

Explanation:

When ammonium nitrate, NH4NO3(s), is added to water at 25 ℃, it dissolves spontaneously and the temperature of the solution decreases. This process is indicative of an endothermic reaction where energy is absorbed during the dissolution of the solute, causing the temperature of the solution to decrease. However, the factor causing the substance to dissolve is a change in entropy (c). The dissolution process results in an increase in entropy due to the increase in disorder that accompanies the formation of the solution, overriding the fact that it's an endothermic process that requires energy input.

Explanation:

An element that gains one electron will tend to acquire a negative charge whereas an element that tend to lose an electron will acquire a positive charge.

Similarly, an element losing two electrons will acquire a 2+ charge.

For example, calcium is a group II element and has 2 valence electrons. Therefore, to attain stability it loses two electrons and thus changes into [tex]Ca^{2+}[/tex] ion.

Hence, we can conclude that an element of Group II loses two electrons in the process of a chemical combination then its ionic charge will be +2.

The amount of heat released is equal to 109.58 KJ/mol when 1.97 g of the methane is combusted.

A combustion reaction can be defined as a reaction that forms fire and occurs at an elevated temperature. It is an exothermic reaction as well as a redox chemical reaction that commonly occurs between a fuel and oxygen gas in the atmosphere.

During the combustion, methane reacts with two molecules of oxygen gas to give carbon dioxide and two molecules of water.

[tex]CH_4 + 2O_2\longrightarrow CO_2+2H_2O[/tex]

The mass of the methane = 1.97 g

The molecular mass of the methane = 16g/mol

The number of the moles of methane = 1.97/16 = 0.123 mol

The enthalpy of combustion for 1 mole of methane,  ΔH° = -890.4 kJ/mol

The heat released during the combustion of 0.123 mol of methane

= 0.123 × 16 = 109.58 KJ/mol

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Final answer:

The Bohr model for silicon primarily describes the atom’s electron configuration and how introducing atoms with different numbers of valence electrons, like phosphorus, affects this configuration and the silicon's electrical properties.

Explanation:

The Bohr model for silicon involves understanding how electrons are arranged around the nucleus of the silicon atom and how this structure is affected by processes such as n-type doping. In its essence, silicon has four valence electrons that participate in forming bonds with neighboring atoms, perfectly filling the valence band in a crystalline lattice.

When an atom like phosphorus, with five valence electrons, is introduced into this lattice, it contributes an extra electron. This extra electron, due to the high dielectric constant of the semiconductor, is bound in a hydrogen-like molecular orbital significantly larger than the orbitals in isolated atoms. This scenario, pertinent to the Bohr model, is critical in understanding semiconductors and their doping which alters electrical properties, primarily by introducing extra charge carriers.

A decimeter (dm) is one tenth of a meter are the unit of length of measurement.  The diameter of Earth is 1.3 x 104 km.,  the diameter expressed in decimeters is 1.352 x 10^7 dm so it is the first one.

It can be defined as the measuring of  the length of objects with some specific units representing the symbol and it can divided into standard or non-standard.

Some measuring tools are ruler, measuring tape used to determine the length. For example, the height of students  can be measured using a feet scale, some units of length measurements are inches, centimeters, meters, feet, etc

The units of length measurement are two types such as Standard and non-standard units of measuring length.

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The parent rock or protolith is key in identifying metamorphic rocks because it helps explain the mineral composition and textural changes that occur through the metamorphic process due to heat and pressure. This direct link between metamorphic rocks and their parent rock is not found in igneous or sedimentary rocks, making the parent rock a unique identifier for metamorphic types.

The concept of the parent rock, or protolith, is crucial in understanding metamorphic rocks because it represents the original, unmetamorphosed rock from which a metamorphic rock was formed. Unlike igneous or sedimentary rocks, metamorphic rocks undergo physical and sometimes chemical changes due to heat and pressure without melting, and these changes often result in patterns or orientations in the minerals, such as foliation.

The composition and texture of a metamorphic rock directly relate to its parent rock, providing clues to the conditions under which it formed. This unique relationship between metamorphic rocks and their parent rock allows geologists to determine the past conditions of the Earth's crust and understand the geological history more completely.

Overall, the identification of the parent rock is essential for classifying metamorphic rocks because it helps to understand the metamorphic processes that the rock has undergone and explains its current mineral composition and texture.

Answer:

The correct option is 6

Explanation:

The first shell of an atom can contain a maximum of two electrons and must be completely filled (with the two electrons) before the next electron shell is considered for filling. The second electron shell can contain a maximum of eight electrons.

If an element has 8 electrons, 2 of this electrons will occupy/completely fill the first electron shell, while the second shell will only contain the remaining 6 electrons.

NOTE: A neutral atom of an element with 8 electrons is oxygen.

Final answer:

Solid zinc sulfate dissolves in water by dissociating into zinc ions (Zn²⁺) and sulfate ions (SO₄²⁻), making it a strong electrolyte. This shows the nature of ionic compounds dissociating in solutions.

Explanation:

The question asks about the reaction when solid zinc sulfate is dissolved in water, incorrectly referencing reactions of zinc with hydrochloric acid and copper(II) sulfate. However, for zinc sulfate in water, the correct dissociation reaction is:

ZnSO₄(s) → Zn²⁺(aq) + SO₄²⁻(aq)

This equation shows that solid zinc sulfate dissociates into zinc ions (Zn²⁺) and sulfate ions (SO₄²⁻) when it is put into water, making it a strong electrolyte. It highlights the process by which ionic compounds like zinc sulfate split into their respective ions in a solution, thereby enhancing the solution's ability to conduct electricity.

Answer: the answer is Z

The balanced equation for the reaction of solid iodine with fluorine gas is I2(s) + 3 F2(g) → 2 IF3(g), indicating one molecule of iodine reacts with three molecules of fluorine to form two molecules of iodine trifluoride.

The student asked for a balanced chemical equation for the reaction between solid iodine (I2) and fluorine gas (F2). The balanced equation for this reaction is:

I2(s) + 3 F2(g) → 2 IF3(g)

This equation indicates that one molecule of solid iodine reacts with three molecules of fluorine gas to produce two molecules of iodine trifluoride gas. In balancing the equation, it is important to ensure that the same number of each type of atom appears on both sides of the equation.

A neutral atom of lithium-6 contains three protons, three neutrons, and three electrons, with an isotope symbol of 6Li or 3Li.

The neutral atom of the isotope lithium-6 contains three protons, three neutrons, and three electrons. The atomic number for lithium, which signifies the number of protons in an atom, is always 3. The mass number of lithium-6 indicates that it has a total of six protons and neutrons, meaning this isotope has three neutrons since the number of protons is known to be three. The isotope symbol for lithium-6 is either 6Li or 3Li, with the mass number given as the superscript before the elemental symbol (Li).