Final answer:
To find the heat produced by the combustion of 2 mol of methane gas, you use the standard enthalpies of formation. The calculated heat produced is -1630.6 kJ.
Explanation:
The question involves using the concept of enthalpy change (ΔH), specifically standard enthalpies of formation (ΔH°f), to calculate the heat produced during the combustion of methane gas (CH4).
Step-by-Step Calculation:
First, write down the balanced chemical equation for the combustion of methane:
CH4(g) + 2O2(g) → CO2(g) + 2H2O(№)
Next, apply Hess's Law using the provided ΔH°f values:
CH4(g): -74.9 kJ/mol
CO2(g): -393.5 kJ/mol
H2O(№): -285.8 kJ/mol
Calculate the total enthalpy change (ΔH) for the reaction:
ΔH = [1 mol(ΔH°f CO2) + 2 mol(ΔH°f H2O)] - [2 mol(ΔH°f CH4)]
ΔH = [1 mol(-393.5 kJ/mol) + 2 mol(-285.8 kJ/mol)] - [2 mol(-74.9 kJ/mol)]
ΔH = (-393.5 kJ - 2×285.8 kJ) - (-2×74.9 kJ)
ΔH = (-393.5 - 571.6 + 149.8) kJ
ΔH = -815.3 kJ
This is the enthalpy change for the combustion of 1 mol of methane. Since we are burning 2 mol of methane, multiply by 2:
Total ΔH = 2 × -815.3 kJ
Total ΔH = -1630.6 kJ
Therefore, the heat produced by burning 2 mol of methane gas is -1630.6 kJ.
Which organelle this illustration represent?
Golgi Apparatus
Mitochondria
Vacuoles
emdoplasmic membrane
Answer:
Option B.Mitochondria
Explanation:
I took a unit test and this question was on it, the mitochondria is the correct answer
Hope this helps
The metric system is only used in France
True
or
False
Each element has its own emission bright line spectrum pattern. True or false?
the answer is true. Each element has it's own emission bright line spectrum pattern
Which state of matter takes both the shape and volume of its container?
a. solid
c. gas
b. liquid
d. both b and c ____ 11. which state of matter is characterized by having an indefinite shape, but a definite volume?
a. gas
c. solid
b. liquid
d. none of the above?
Answer:
For 10: The correct answer is Option c.
For 11: The correct answer is Option b.
Explanation:
There are 3 states of matter:
Solid state: In this state, the particles are closely packed and does not have any space between them. Thus, this state of matter has the highest intermolecular forces of attraction.
This state have a definite shape and volume.
Liquid state: In this state, the particles are present in random and irregular pattern. The particles are closely arranged but they can move from one place to another. The intermolecular forces between the particles are less as compared to the solid state.
This state have a definite volume but does not have a fixed shape as they can take up the shape of container in which they are kept.
Gaseous state: In this state, the particles are loosely arranged and have a lot of space between them. Thus, this state of matter has the lowest intermolecular forces of attraction.
This state have indefinite volume as well as shape. It can take up the volume and shape of the container in which they are kept.
From the above information:
For 10: The state of matter which takes up the shape and volume of the container is gaseous state.
Hence, the correct answer is Option c.
For 11: The state of matter which has indefinite shape but have a definite volume is liquid state.
Hence, the correct answer is Option b
A gas takes both the shape and volume of its container, while a liquid has a definite volume but takes the shape of its container. A solid does not conform to the container's shape or volume.
States of matter are characterized by their ability to take the shape and volume of their containers. The state of matter that takes both the shape and volume of its container is the gas state. This is because the particles in a gas are spread out and can move freely to fill any space available. On the other hand, a liquid has a definite volume but takes the shape of its container. Conversely, a solid does not change to fit the shape or volume of its container as its particles are tightly packed and only vibrate in place.
Which state of matter takes both the shape and volume of its container?
The answer is gas (c), as gases will expand to fill the entire volume of their container and take its shape.
Which state of matter is characterized by having an indefinite shape but a definite volume?
The answer is liquid (b). Liquids have a fixed volume but will flow and change their shape to conform to the shape of their container, without changing volume.
Hydrogen gas was collected by water displacement. what was pressure of the h2 collected if the temperature was 26°c?
The pressure of the hydrogen gas collected by water displacement at a temperature of 26°C is obtained by measuring the height of the displaced mercury, considering the presence of water vapor and it is calculated as 725 torr.
Explanation:
The question is requesting the pressure of hydrogen gas collected by water displacement at a temperature of 26°C. The pressure of a gas sample can be determined using a variety of methods. One such approach is measuring the displacement of a column of mercury. If the column of mercury is 26.4 cm high, the pressure of the gas is equivalent to this height, or 264 torr.
However, the presence of water vapor can affect the calculated pressure of the gas. At 26°C, the pressure of water vapor is 25.2 torr. Hence, we need to subtract this value from the total pressure to obtain the pressure of hydrogen gas.
Therefore, the pressure of the hydrogen gas collected by water displacement at a temperature of 26°C is 725 torr.
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The pressure of the collected hydrogen gas is equal to the atmospheric pressure.
Explanation:A sample of hydrogen gas was collected by water displacement at 26°C. To determine the pressure of the collected hydrogen gas, we need to consider the relationship between pressure, volume, temperature, and the number of moles of gas.
Using the ideal gas law, we can calculate the number of moles of hydrogen gas from the volume and temperature. Then, using the molar mass of hydrogen gas, we can determine the mass of the collected gas. Finally, we can relate the mass of the gas to the pressure using the density formula.
Since the hydrogen gas was collected by water displacement, we can assume that it occupies the same volume as the displaced water. Given the temperature of 26°C (299 K) and assuming atmospheric pressure (1 atm), we can calculate the number of moles of hydrogen gas using the ideal gas law.
Once the number of moles is known, we can determine the mass of the hydrogen gas using its molar mass (2.016 g/mol). Finally, we can calculate the pressure of the gas using the density formula, considering the mass of the gas and the volume of the displaced water.
Therefore, the pressure of the collected hydrogen gas is approximately 1 atm, which is the same as the atmospheric pressure.
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How do the electrons in bonds (bonding domains) differ from lone pairs (non-bonding domains)?
The electrons in bonds (bonding domains) differ from lone pairs (non-bonding domains) is because the bonding domains are bonded to the central atom vs the lone pairs are just stuck on as extra electrons. The difference of bonding domains from non-bonding domains is that the bonding domains are bonded to the central atom and the non-bonding domains are just stuck on as extra electrons.
Answer:
The bonding electrons are different from nonbonding electrons by the arrangement with the central atom. Bonding electrons are bonded with the central atom. Nonbonding electrons appear are electron clouds.
Explanation:
During the formation of a chemical bond, there are bonding electrons and loan pairs.
The electrons of both the atom in a chemical bond share with each other and form a stable sigma bond. The electrons are linearly bonded with each other.
The electrons which are not directly bonded with other atoms, occupy the space at the top and bottom of the sigma bond. These electrons are present as the electron cloud and are termed the non-bonding electrons.
The bonding electrons differ from non-bonding electrons as bonding electrons are bounded by the central atom. Loan pair of electrons or nonbonding electrons are present as the electron cloud above or below the bond.
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What are the two measurement systems the thermometer uses? Which one is most commonly used for science? Why?
Giraffes with short necks lived in arid regions. Over time, grasses disappeared, forcing giraffes to eat from trees. Mutations in the genome led to some giraffes inheriting the trait for long necks. Over time, there were more giraffes with long necks in the region. What are the two reasons for the change in the population of giraffes? (More than one answer)
- adaptation?
- artificial selection?
- natural selection?
- harmful genetic traits?
Answer: adaptation
natural selection
Natural selection refers to the differential survival of the organisms in the population. It describe the fact that individual that have favorable phenotypic characteristics have better chances of survival over others in the changing environment. Adaptation is a genetic change or mutation that helps organism to survive in it's ecological niche. Due to the helpful nature of these genetic changes they are passed down from one generation to the next generation and favors the survival and abundance of a species.
Adaptation and natural selection has resulted in the change in the population of the giraffes. The giraffes being in short neck adapted the increase in neck length with an effort to obtain leaves from tall tries. The long neck giraffe got the better chances of survival and reproduction, due to natural selection the trait was passed on to generation. This resulted in the evolution of long neck giraffe species.
Which shows the temperatures of three substances, in order, from greatest to least?water vapor, ice, waterice, water, water vaporwater, water vapor, icewater vapor, water, ice?
The temperatures of three substances in order from greatest to least is
Water vaporWaterIceWhat is Temperature?This is the degree of hotness or coldness of a substance. It is also the
average kinetic energy present in a body.
Higher temperatures usually have the highest average kinetic energy.
Gases have the highest kinetic energy while Solids have the least kinetic
energy. In the case of Water, the gaseous form is Water vapor and the
solid form is Ice.
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What are the subatomic particles found in the electron shell of the atom?
Electrons are the smallest of the three particles that make up atoms. Electrons are found in shells or orbitals that surround the nucleus of an atom. Protons and neutrons are found in the nucleus. They group together in the center of the atom.
The electron shell of an atom contains electrons, negatively charged subatomic particles. Protons and neutrons, the other subatomic particles, reside in the atom's nucleus.
The electron shell of an atom contains one type of subatomic particle known as the electron. Electrons are very small particles with a negative charge, often represented by 'e⁻' in scientific notation. In contrast, two other subatomic particles, the proton and neutron, are located in the nucleus of the atom. Protons have a positive charge and are denoted by 'p⁺', while neutrons have no charge and are represented by 'n' or 'n⁰'. The combination of electrons, protons, and neutrons constitutes the fundamental architectural makeup of an atom, determining its element, isotopes, and chemical behavior.
Why did Rutherford conclude that the atom was mostly empty space?
Rutherford deduced that an atom is mostly empty space because most alpha particles in his experiment passed through the gold foil unabated; only a few particles deflected due to the presence of a small, dense, positively charged nucleus.
Rutherford concluded that the atom was mostly empty space based on his gold foil experiment. He observed that the vast majority of the alpha particles passed through the gold foil without deflection, indicating that they encountered no significant obstacle, hence most of the atom was empty space. A very small number of alpha particles were deflected at large angles, and even fewer were deflected straight back, which suggested that they interacted with something very small and with a substantial positive charge and mass. This led Rutherford to propose the nucleus, a tiny, dense center within the atom composed of protons and neutrons. He surmised that the electrons orbit this nucleus, much like planets around the sun, in what is known as the planetary model of the atom.
Consider a neutrally charged atom that has an atomic mass number of 80, which includes 35 neutrons. how many electrons does this atom have?
Answer:
45 electrons.
Explanation:
mass number = 80
no. of neutrons = 35
Given that it is a neutrally charged atom,
no. of electrons = mass no. - no. of neutrons
= 80 - 35
= 45 electrons.
Chromium metal is added to a solution of nickel(ii) sulfate. what is the balanced chemical reaction? hints
A compound that changes color when it is placed into an acidic or a basic solution is a compound that changes color when it is placed into an acidic or a basic solution is protonated. amphiprotic. an acid-base indicator. a buffer.
is MgBr2 a covalent bond or an ionic bond
In the given question, [tex]\rm MgBr_2[/tex] is an ionic bond. The correct answer is option 2.
A covalent bond is a type of chemical bond in which two atoms share one or more pairs of electrons.
Ionic bonds is formed between a metal and a nonmetal, where one atom gives up an electron to another atom. In [tex]\rm MgBr_2[/tex], magnesium (Mg) is a metal and bromine (Br) is a nonmetal. Magnesium gives up two electrons to bromine, forming an ionic bond.
Therefore, option 2. ionic bond is the correct answer.
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Number of atoms in 5.40gB
To calculate the number of atoms in 5.40g of Boron, we first convert grams to moles using Boron's atomic weight, resulting in 0.5 moles. Then, using Avogadro's number (6.022 x 10²³ atoms/mole), we can find the number of atoms. Hence, 5.40g of Boron contains approximately 3.011 x 10²³ atoms.
Explanation:The number of atoms in 5.40g of Boron (B) can be found by first determining the number of moles. Boron's atomic weight is approximately 10.81 g/mol. Therefore, 5.40g of Boron would consist of 0.5 moles.
Next, using Avogadro's number (approximately 6.022 x 10²³atoms/mole), used to convert moles to atoms, we can find out the number of atoms.
Therefore, 5.40g of Boron contains approx 3.011 x 10^23 atoms.
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∠3 and ∠4 are _______.
supplementary angles
complementary angles
vertical angles
congruent
Answer : The [tex]\angle 3\text{ and }\angle 4[/tex] are, supplementary angles.
Explanation :
Supplementary angles : The two angles are supplementary angle in whcih the the sum of those two angle are [tex]180^o[/tex]
Complementary angles : The two angles are complementary angle in whcih the the sum of those two angle are [tex]90^o[/tex]
Vertical angles : Vertical angles are the angles that are opposite to each other when two lines intersect each other.
Congruent angle : It is defined as they have the same angles.
From the above information we conclude that,
[tex]\angle 1\text{ and }\angle 2[/tex], [tex]\angle 2\text{ and }\angle 3[/tex], [tex]\angle 3\text{ and }\angle 4[/tex] and [tex]\angle 4\text{ and }\angle 1[/tex] are the supplementary angles.
[tex]\angle 1\text{ and }\angle 3[/tex] and [tex]\angle 2\text{ and }\angle 4[/tex] are the vertical angles.
Hence, the [tex]\angle 3\text{ and }\angle 4[/tex] are, supplementary angles.
What do the elements sulfur (s), nitrogen (n), phosphorus (p), and bromine (br) have in common? refer to the periodic table for help?
Answer:
They have the same number of valence electrons.
Which of the following planets has a shorter year than Earth, as measured in Earth days? A. Uranus B. Mercury C. Saturn D. Jupiter
Mercury is the answer
Please help quickly!! Will give brainiest to the first correct answer when I can!
Which of the following pairs of elements would most likely form a salt? (Not C)
A. Ca and Br
B. H and He
C. Cl and Fl
D. Na and Ca
What is the isotope with 50 protons, 68 neutrons, and 50 electrons?
Tin -118 is the isotope with 50 protons, 68 neutrons, and 50 electrons.
What is an isotope?Isotopes can be described as elements that contain the same atomic number but a different atomic mass. Isotopes of an element possess an equal number of electrons and protons. The number of neutrons in the respective nucleus of that element is different.
For example, the isotope of oxygen can be written as oxygen- 16, oxygen - 17, and oxygen-18 as all of them contain eight electrons or protons.
Tin metal has 29 isotopes but all the isotopes have the same number of electrons and protons. Among these only ¹²⁶Sn isotope is long-lived while the rest 28 isotopes of tin with a half-life of less than one year. The mass number of the given isotope of tin = 50 + 68 = 118. Therefore, the given isotope of tin is ¹¹⁸Sn. It has an abundance of 24.22%.
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Which of the following statements correctly describe metalloids?
- Metalloids are elements that have both metal and nonmetal properties
- Metalloids are metals that do not lose
-Metalloids are metals that do not attract electrons
-Metalloids are elements that only have metal properties Save
The statements that describe metalloids are these are elements that have both metal and nonmetal properties. The correct option is A.
What are metalloids?Metalloids are chemical elements that have the properties of both metals and non-metals. Metalloids are brittle and good conductors of electricity. They form alloys with metals. They have various chemical and physical properties that are used in many things like catalysis, flame, or glasses.
So, metalloids are elements that contain both metals and non-metals. They are not the metals that don't lose. They always do not attract electrons and only metal properties are also wrong because it has the properties of both.
Thus, the correct option is A. Metalloids are elements that have both metal and nonmetal properties.
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Amanda dropped a rock into a graduated cylinder containing water. The water level in the cylinder increased. Which property of the rock is this experiment designed to measure A. Density B. Weight C. Volume D. Mass
Amanda dropped a rock into a graduated cylinder containing water. The water level in the cylinder increased. Density is the property of the rock.
What is density?Density is the mass of a specific material per unit volume. d = M/V, at which d is density, M is weight, and V is volume, is the formula for density. Grams per cubic centimeter are a typical unit of measurement for density. For instance, whereas Earth has a density of 5.51 grams, water has a density of 1 grams.
Another way to state density is in kilograms per cubic meter (in metre-kilogram-second or SI units). For instance, air weighs 1.2 pounds per cubic metre. Amanda dropped a rock into a graduated cylinder containing water. The water level in the cylinder increased. Density is the property of the rock.
Therefore, the correct option is option A.
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What happens when an electron moves to a higher energy level? the atom loses the electron. the atom becomes more stable. the electron gains energy?
N writing a chemical equation that produces hydrogen gas, the correct representation of hydrogen gas is
Answer:
H2
Explanation:
The 2 in this equation is supposed to be little.
What factors affect water quality?In a typical drinking-water treatment process, ____________________ is when air is forced through the water to reduce unpleasant odors and taste.
In a popular classroom demonstration, solid sodium is added to liquid water and reacts to produce hydrogen gas and aqueous sodium hydroxide. part a write a balanced chemical equation for this reaction.
Define chemical element and list the four elements that form the bulk of body matter
How many valence electrons does a helium atom have? what is the formula of the ion formed when potassium achieves noble-gas electron configuration?
> How many valence electrons does a helium atom have?
The electron configuration of Helium is simply 1s2. We see that its outermost shell is the s shell and it contains 2 electrons, therefore the number of valence electrons is also 2.
> What is the formula of the ion formed when potassium achieves noble-gas electron configuration?
Potassium has a electron configuration of [Ar] 4s1. To have an electron configuration of only [Ar] which is a noble gas, the one electron from 4s1 should be removed, hence:
K+
Consider n2 (g) + 3h2 (g) →→ 2nh3 (g). what is the mass of nitrogen gas required to react with 0.129 g h2?
Answer:pookie dookie
Explanation: