Answer: Between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.
Gas exchange in the lungs occurs in the alveoli. Oxygen diffuses from the alveoli into the blood, while carbon dioxide diffuses from the blood into the alveoli.
Gas exchange in the lungs, also referred to as pulmonary gas exchange, primarily occurs in the alveoli. The alveoli are tiny, grape-like clusters surrounded by networks of thin-walled pulmonary capillaries.
Here is a step-by-step explanation of the gas exchange process:
When you inhale, air enters the alveoli, which have a higher concentration of oxygen compared to the blood in the surrounding capillaries.Oxygen diffuses from the alveoli into the blood because of this concentration gradient.Conversely, the blood in the capillaries has a higher concentration of carbon dioxide than the alveoli, causing carbon dioxide to diffuse into the alveoli.This exchange of gases allows oxygenated blood to travel through the pulmonary veins to the rest of the body, while carbon dioxide is expelled when you exhale.The vast number of alveoli (around 300 million per lung) provides a large surface area, maximizing the efficiency of gas exchange.
A dilute aqueous potassium nitrate solution is
Answer:
A dilute aqueous potassium nitrate solution is a homegeneous mixture.
Explanation:
What is the maximum magnification of a compound light microscope?
Answer: 100x
Explanation:
The actual power or magnification of a compound optical microscope is the product of the powers of the ocular (eyepiece) and the objective lens. The maximum normal magnifications of the ocular and objective are 10× and 100× respectively, giving a final magnification of 1,000×.
The molecule CH2O contains two single bonds and one double bond. True or False
Answer:
True
Explanation:
CH2O is a polar molecule. It has three polar bonds that are arranged asymmetrically, thus allowing their dipole moments to add up and give the molecule an overall dipole moment. CH2O has a central carbon atom that forms two single bonds with the two hydrogen atoms and a double bond with the oxygen atom.
Answer: The given statement is true.
Explanation:
As the given molecule is [tex]CH_{2}O[/tex]. Name of this compound is formaldehyde as it contains aldehyde functional group, that is, CHO group.
In this molecule, carbon is the central atom and both the hydrogen atoms are attached to the carbon atom through one single bond each.
Whereas oxygen is also attached to the carbon atom but through a double bond.
Therefore, we can conclude that the statement molecule [tex]CH_{2}O[/tex] contains two single bonds and one double bond, is true.
The biosphere of the earth is made up of _______compounds.
A. Inorganic
B. Organic
Answer:
B.
Explanation:
When we say "biosphere", we're referring to the atmosphere, geosphere, lithosphere and hydrosphere, and everything in them. You've probably heard of these in class as the "pillars of Earth" or the "pillars of our planet". In other words, when we talk about biosphere we're talking about life.
Organic compounds are all of the compounds that contain carbon, C, in them. You might know that CHNOPS* are the "7 molecules of life", and you might have noticed that Carbon stands first in the list, and that's not because it makes up a mnemonic, Carbon is indeed the most important one in many ways.
*Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus and Sulfur.
Hope it helped,
BiologiaMagister
Answer:
Organic :)
Explanation:
Consider the equilibrium system:
2ICl(s) ⇄ I2(s) + Cl2(g)
Which of the following changes will increase the total amount of of Cl2 that can be produced?
All of the listed answers are correct
decreasing the volume of the container
removing the Cl2 as it is formed
adding more ICl(s)
removing some of the I2(s)
Answer:
removing the Cl₂ as it is formed .
adding more ICl(s) .
removing some of the I₂(s).
Explanation:
Le Châtelier's principle states that when there is an dynamic equilibrium, and this equilibrium is disturbed by an external factor, the equilibrium will be shifted in the direction that can cancel the effect of the external factor to reattain the equilibrium.
1) Decreasing the volume of the container:
Decreasing the volume of the container will increase the pressure.When there is an increase in pressure, the equilibrium will shift towards the side with fewer moles of gas of the reaction. And when there is a decrease in pressure, the equilibrium will shift towards the side with more moles of gas of the reaction.The reactants side (left) has no moles of gases and the products side (right) has 1.0 mole of gases.So, increasing the pressure will shift the reaction to the side with lower moles of gas (left side) and so the total amount of Cl₂ produced is decreased.so, decreasing the volume of the container will decrease the total amount of Cl₂ produced.
2) Removing the Cl₂ as it is formed:
Removing Cl₂ gas will decrease the concentration of the products side, so the reaction will be shifted to the right side to suppress the decrease in the concentration of Cl₂ gas by removing and so the total amount of Cl₂ produced is increased.so, removing the Cl₂ as it is formed will increase the total amount of Cl₂ produced.
3) Adding more ICl(s) :
Adding ICl(s) will increase the concentration of the reactants side, so the reaction will be shifted to the right side to suppress the increase in the concentration of ICl(s) by addition and so the total amount of Cl₂ produced is increased.so, adding more ICl(s) will increase the total amount of Cl₂ produced.
2) Removing some of the I₂(s):
Removing I₂ gas will decrease the concentration of the products side, so the reaction will be shifted to the right side to suppress the decrease in the concentration of Cl₂ gas by removing and so the total amount of Cl₂ produced is increased.so, removing some of the I₂(s) will increase the total amount of Cl₂ produced.
the following changes will increase the total amount of of Cl2 that can be produced:
removing the Cl₂ as it is formed .adding more ICl(s) .removing some of the I₂(s).The change that can increase the total amount of Cl2 produced would be the removal of Cl2 as it is being formed.
EquilibriumWhen a reaction is in equilibrium and one of the constraints that affect the rate of reactions is introduced, the equilibrium shifts so as to annul the effects of the introduced constraint.
Thus, if Cl2 is constantly being removed from the reaction vessels, the reaction will adjust in order to return to equilibrium, thus more Cl2 is produced.
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What relationships can be determined from a balanced chemical equation?
Answer:
From a balanced chemical equation the relationships of the amount of reactants and products, either as number of units (moles) or as mass (grams), can be determined.
Explanation:
Since reactants combine in a fixed ratio to form a fixed amount of products, the law of mass conservation permits to state cuantitative relationships between the amounts of rectants and products, and this is represented through a balanced chemical equation.
The balanced chemical equation represents the reactants and products using the chemical composition of each substance (consisting of chemical symbols and subscritps) and shows the relations in which they react or are produced using numbers as coefficients.
For example:
Balanced chemical equation: 1CH₄(g+ 2O₂(g) → 1CO₂(g) + 2H₂O(g)Relationships:1 molecule CH₄ : 2 molecules O₂ : 1 molecule CO₂ : 2 molecules H₂O
1 mole CH₄ : 2 moles O₂ : 1 mole CO₂ : 2 moles H₂O
16.04 g CH₄ : 64.00 g O₂ : 44.01 g CO₂ : 36.03 g H₂O
(80.04 g reactants = 80.04 g products)
A balanced chemical equation is a concise representation that provides a wealth of information about the quantitative and qualitative aspects of a chemical reaction. It is a fundamental tool in chemistry for predicting and understanding the relationships between reactants and products.
The relationships that can be determined from a balanced chemical equation include:
1. Stoichiometry: The stoichiometry of a balanced equation gives the quantitative relationship between the amounts of reactants and products. The coefficients in the equation represent the moles of each substance involved in the reaction. For example, in the reaction [tex]\(2H_2 + O_2 \rightarrow 2H_2O\)[/tex], the coefficients indicate that two moles of hydrogen gas react with one mole of oxygen gas to produce two moles of water.
2. Mass Conservation: A balanced chemical equation obeys the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction. The total mass of the reactants must equal the total mass of the products. This allows for the prediction of the masses of reactants needed or products formed.
3. Molecular Composition: The equation shows the molecular formulae of the reactants and products, indicating the composition of each substance in terms of atoms of different elements.
4. Chemical Equivalence: The equation provides information about the chemical equivalence of the reactants and products. For instance, it shows how many moles of one reactant are chemically equivalent to a certain number of moles of another reactant or product.
5. Reaction Type: The equation can indicate the type of reaction, such as synthesis, decomposition, single replacement, double replacement, combustion, or acid-base reaction.
6. Energy Change: Although not explicitly shown in the equation, a balanced chemical equation can imply an exothermic or endothermic reaction through the presence of energy terms (such as heat, [tex]\(q\)[/tex], or enthalpy change, [tex]\(\Delta H\))[/tex] if included.
7. State of Matter: The equation may include symbols for the physical states of the reactants and products (solid, liquid, gas, aqueous), which can be important for setting up experiments or understanding reaction conditions.
8. Concentration Changes: For reactions in solution, the equation can be used along with the reaction stoichiometry to determine changes in concentration of reactants and products over time.
9. Limiting Reactant: By comparing the mole ratios of reactants in a balanced equation, one can determine the limiting reactant, which is the reactant that will be completely consumed first and thus limits the amount of product formed.
10. Theoretical Yield: Using the balanced equation and the mole ratio between reactants and products, the theoretical yield of a reaction can be calculated, which is the maximum amount of product that can be formed from a given amount of reactant(s).
In summary, a balanced chemical equation is a concise representation that provides a wealth of information about the quantitative and qualitative aspects of a chemical reaction. It is a fundamental tool in chemistry for predicting and understanding the relationships between reactants and products.
Listenwhich change in the h+ ion concentration of an aqueous solution represents a decrease of one unit on the ph scale?
Answer:
Explanation:
The pH scale is a logarithmic scale that runs from 1 to 14.
1 is the lower limit of the scale and 14 is the upper limit of the scale. On a pH scale, to represent a decrease of one unit, the concentration of the hydrogen ion or the hydroxyl ion must change.
A decrease in 1 unit or 1 pH represents a concentration of 10moldm⁻³.
Note: pH= -log₁₀[H⁺]
Given the three equations below, what is the heat of reaction for the production of glucose, C6H12O6, as described by this equation? 6C(s) + 6H2(g) + 3O2(g) → C6H12O6(s) C(s) + O2(g) → CO2(g), ∆H = –393.51 kJ H2(g) + ½ O2(g) → H2O(l), ∆H = –285.83 kJ C6H12O6(s) + 6O2(g) → 6CO2(g) + H2O(l), ∆H = –2803.02 kJ
Answer:
- 1273.02 kJ.
Explanation:
This problem can be solved using Hess's Law.
Hess's Law states that regardless of the multiple stages or steps of a reaction, the total enthalpy change for the reaction is the sum of all changes. This law is a manifestation that enthalpy is a state function.
We should modify the given 3 equations to obtain the proposed reaction:6C(s) + 6H₂(g) + 3O₂(g) → C₆H₁₂O₆(s),
We should multiply the first equation by (6) and also multiply its ΔH by (6):
6C(s) + 6O₂(g) → 6CO₂(g), ∆H₁ = (6)(–393.51 kJ) = - 2361.06 kJ,
Also, we should multiply the second equation and its ΔH by (6):
6H₂(g) + 3O₂(g) → 6H₂O(l), ∆H₂ = (6)(–285.83 kJ) = - 1714.98 kJ.
Finally, we should reverse the first equation and multiply its ΔH by (- 1):
6CO₂(g) + H₂O(l) → C₆H₁₂O₆(s) + 6O₂(g), ∆H₃ = (-1)(–2803.02 kJ) = 2803.02 kJ.
By summing the three equations, we cam get the proposed reaction:
6C(s) + 6H₂(g) + 3O₂(g) → C₆H₁₂O₆(s),
And to get the heat of reaction for the production of glucose, we can sum the values of the three ∆H:
∆Hrxn = ∆H₁ + ∆H₂ + ∆H₃ = (- 2361.06 kJ) + (- 1714.98 kJ) + (2803.02 kJ) = - 1273.02 kJ.
Answer:
- 1273.02 kJ
Explanation:
As an alternative energy source, nuclear energy is more harmful to the environment than a coal-fired power plant because it produces more mercury, air pollution, and carbon dioxide.
True
or
false
Answer:
False
Explanation:
It is coal-fired power plants that produce mercury, air pollution, and carbon dioxide.
However, nuclear energy produces radioactive waste that must be stored for many years before it can be safely disposed.
Who is considered the founder of the periodic table of the elements?
Answer:
Dmitry Mendeleev
Explanation:
Around 1869 a Russian scientist, Dmitry Mendeleev formed what is now known as the periodic table or chart. The Mendeleevian periodic table was based on the atomic weights of elements using the periodic law. The periodic law states that "chemical properties of elements are a periodic function of their atomic weights".
The modern periodic table was re-stated by Henry Moseley in the 1900s. He changed the basis of the periodic law to atomic masses.
Compared to the Apollo program, the Space Shuttle has been
A. a complete failure.
B. much more successful.
C. considered a mixed success.
D. able to explore much more of the solar system.
your answer is C. considered a mixed success.
An empty fuel tank can still contain ________ and therefore can be even more dangerous than one full of liquid fuel.
Answer:
An empty fuel tank can still contain "fumes"
Explanation:
Even if there is not enough liquid fuel, whatever is left in the tank creates fumes, which is more combustible than liquid gas.
Answer:
Fumes / vapors.
Explanation:
An empty tank appears to be non dangerous as it has no liquid fuel. However even if tank is empty there may be some drops of left over liquid fuel.
These drops make the container filled with dangerous vapors that are more prone to catch fire as compared to gasoline.
Even a small spark may cause a severe explosion.
Which of the following would likely form a heterogeneous mixture? Sugar and waterSalt and waterSand and waterBaking soda and water
Answer:
Sand and water
Explanation:
Answer:
Water and sand
Explanation:
the prefix hetero- means 'different' so a heterogeneous mixture would be a mixture in which you can clearly see all of the components.
(like a salad)
sugar and baking soda would dissolve in the water (that would be an example of a homogeneous mixture, the prefix homo- means 'same' homogeneous mixtures have a uniform appearance throughout)
However the sand will definitely not dissolve in the water, it will simply sink to the bottom, and stay there. you would clearly be able to see both the water and the sand.
So the answer can be, none other than
Water and sand.
Which isomers can have different physical or chemical properties?
structural isomers only
geometric isomers only
both structural isomers and geometric isomers
neither structural isomers nor geometric isomers
Explanation:
isomers Chemical compounds having the same molecular formula but different properties due to the different arrangement of atoms within the molecules. Structural isomers haveatoms connected in different ways. Geometric isomers, also called cis-trans isomers, differ in their symmetry about a double bond.
Answer: Option (b) is the correct answer.
Explanation:
A geometric isomer is defined as an isomer that contains different arrangement of groups across the double bond, ring etc. Generally, coordination compounds show geometric isomers.
For example, cis-2,butene and trans-2,butene are geometrical isomers.
Geometrical isomers cause change in geometry of a compound. Due to this both physical and chemical properties of a substance changes.
On the other hand, structural isomers are the isomers that have same chemical formula but different structure due to different sequence of atoms present in the formula.
For example, butane and isobutane are structural isomers.
Therefore, we can conclude that geometric isomers only have different physical or chemical properties. ty
A flask contains methane, chlorine, and carbon monoxide gases. The partial pressures of each are 0.215 atm, 50 torr, and 0.826 respectively. What is the total pressure in the flask?
Answer:
1.11 Atm or 1.0168Atm or 841.168 Torr or 841 Torr
Explanation:
we are using Daltons partial pressure is equal to the sum of the partial pressures of the individual gases. you must convert the Torr to Atm
Phosgene (carbonyl chloride), COCl2, is an extremely toxic gas that is used in manufacturing certain dyes and plastics. Phosgene can be produced by reacting carbon monoxide and chlorine gas at high temperatures: CO(g)+Cl2(g)⇌COCl2(g) Carbon monoxide and chlorine gas are allowed to react in a sealed vessel at 479 ∘C . At equilibrium, the concentrations were measured and the following results obtained: Gas Partial Pressure (atm) CO 0.720 Cl2 1.17 COCl2 0.170 What is the equilibrium constant, Kp, of this reaction?
Answer:
Kp = 0.202.
Explanation:
For the following reaction:CO(g) + Cl₂(g) ⇌ COCl₂(g),
Kp = (P of COCl₂)/(P of CO)(P of Cl₂)
P of COCl₂ = 0.17 atm, P of CO = 0.72 atm, P of Cl₂ = 1.17 atm.
∴ Kp = (P of COCl₂)/(P of CO)(P of Cl₂) = (0.17 atm)/(0.72 atm)(1.17 atm) = 0.202.
What natural processes produce large quantities of co2
Answer:
here are both natural and human sources of carbon dioxide emissions. Natural sources include decomposition, ocean release and respiration. Human sources come from activities like cement production, deforestation as well as the burning of fossil fuels like coal, oil and natural gas.
Explanation:
The majority of the carbon dioxide emitted into the atmosphere comes from natural sources. The oceans emit the most carbon dioxide per year of any natural or human-caused source.
What are the ways that carbon dioxide released into environment?Carbon dioxide is naturally added to the atmosphere by organisms respiring or decomposing (decaying), carbonate rocks weathering, forest fires, and volcanoes erupting.
Carbon dioxide is also released into the atmosphere as a result of human activities such as the combustion of fossil fuels and the destruction of forests, as well as the manufacture of cement.
Electricity and heat, agriculture, mass transit, forestry, and manufacturing are the primary sources of greenhouse gas emissions worldwide. Energy production in general accounts for 72 percent of total emissions.
Natural sources account for the vast majority of carbon dioxide emissions into the atmosphere. The oceans transmit one of most Carbon dioxide per year of any natural or man-made source.
Thus, this is the natural processes that produce large quantities of carbon dioxide.
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A runner wants to run 13.1 km . She knows that her running pace is 6.2 mi/h .How many minutes must she run? Hint: Use 6.2 mi/h as a conversion factor between distance and time.
Answer:
79 minutesExplanation:
1) Convert the distance, 13.1 km to miles
Conversion factor:1 = 1 mi / 1.61 km
13.1 km [ 1 mi / 1.61 km ] = 8.1336 mi2) Use 6.2 mi/h as a converstion factor between distance and time
8.1366 mi × 1 / [6.2 mi/h] = 1.3124 h3) Convert 1.3124 h to minutes
1.3124 h × [ 60 min/h] = 78.7 minRounding to the nearest minutes (two significant figures):
79 min ← answerThe forensic technician at a crime scene has just prepared a luminol stock solution by adding 15.0 g of luminol into a total volume of 75.0 mL of H2O. What is the molarity of the stock solution of luminol?
Answer:
1.13 M.
Explanation:
Molarity (M) is defined as the no. of moles of solute dissolved in a 1.0 L of the solution.M = (no. of moles of luminol)/(Volume of the solution (L).
∵ no. of moles of luminol = (mass/molar mass) of luminol = (15.0 g)/(177.16 g/mol) = 0.085 mol.
Volume of the solution = 75.0 mL = 0.075 L.
∴ M = (no. of moles of luminol)/(Volume of the solution (L) = (0.085 mol)/(0.075 L) = 1.13 M.
In a conductivity apparatus, like the one above, you should never touch the ___ while the power is on. A Light Bulb B Leads C Wires D Base of the battery
Answer:
Leads
Explanation:
In the conductivity apparatus, you should never touch Leads while the power is on. Hence, option B is correct.
What is leads?Lead (Pb) is a metal.
If a person touches a live conductor, a current may flow through the body to the ground and cause a shock.
That's why in the conductivity apparatus, you should never touch Leads while the power is on.
Hence, option B is correct.
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How does carbon move from living things to the atmosphere
Answer:
Each time you exhale, you are releasing carbon dioxide into the atmosphere. Animals and plants get rid of carbon dioxide gas through a process called respiration. Carbon moves from fossil fuels to the atmosphere when fuels are burned.
Answer:
Animals and plants need to get rid of carbon dioxide gas through a process called respiration. Carbon moves from fossil fuels to the atmosphere when fuels are burned. When humans burn fossil fuels to power factories, power plants, cars and trucks, most of the carbon quickly enters the atmosphere as carbon dioxide gas.
Explanation:
Carbon moves from living things to the atmosphere. Each time you exhale, you are releasing carbon dioxide gas (CO2) into the atmosphere. Animals and plants need to get rid of carbon dioxide gas through a process called respiration. Carbon moves from fossil fuels to the atmosphere when fuels are burned.
How many grams of NaOH are needed to make 0.250 liter of a 0.500 M solution of NaOH? 0.125 g 5.00 g 2.00 g
Answer:
5.00g
Explanation:
Molarity is moles per liter
Therefore:
x moles/.250L = .5 moles/1L
Solve for x: .125 moles required
Question asks for grams of NaOH so multiply the moles by the molar mass of NaOH
.125(39.997) = 4.999625g
Rounds to 5.00g
Answer:
Explanation:
0.5 times 39.98(mass of NaOH) = 19.99.../ 0.25= 4.99 so 5.00
An ideal gas at a given initial state expands to a fixed final volume. would the work be greater if the expansion occurs at constant pressure or at constant temperature? explain.
Answer:
Constant pressure
Explanation:
At constant pressure,
[tex]w = -p\Delta V = -p(V_{f} - V_{i})[/tex]
At constant temperature,
[tex]w = -RT \ln \left(\dfrac{V_{f}}{V_{i}} \right)[/tex]
1 mol of an ideal gas at STP has a volume of 22.71 L.
Let's compare the work done as it expands under each condition from an initial volume of 22.71 L.
Isobaric expansion
[tex]w = -100p(V_{2} - 22.71}); \text{(1 bar$\cdot$L = 100 J)}[/tex]
A plot of -w vs V₂ gives a straight line (red) with a constant slope of 100 J/L as in the diagram below (Note that w is work done on the system, so -w is the work done by the system). \
Isothermal expansion
[tex]w= -8.314 \times 273.15 \ln \left(\dfrac{V_{f}}{22.71} \right)\\\\= -2271 \left( \ln V_{f} -\ln22.71 \right)\\= -2271 \left(\ln V_{f} - 3.123 \right)\\= 7092 - 2271\ln V_{f}[/tex]
A plot of -w vs V₂ is a logarithmic curve. Its slope starts at 100 J/mol but decreases as the volume increases (the blue curve below).
Thus, the work done during an expansion at constant pressure is greater than if the system is at constant temperature.
Which element is least likely to undergo a chemical reaction
Answer:
Neon is the least likely to undergo chemical reaction.
Explanation:
The other elements given in the option do not have 8 electrons in their outermost shell, so they will be quite willing to undergo chemical reactions in order to become stable.
Initially a beaker contains 225.0 mL of a 0.350 M MgSO4 solution. Then 175.0 mL of water are added to the beaker. Find the concentration of the final solution
Answer:
came
Explanation:
Answer:
400.0
Explanation:
I just got it right
Milk of magnesia (maalox) contains magnesium hydroxide. magnesium hydroxide can be reacted with hydrochloric acid to form magnesium chloride and water, as seen in the reaction below. using this reaction, how many grams of hydrochloric acid are needed to fully react 355g magnesium hydroxide?
The chemical reaction described by the question:
[tex]Mg(OH)_{2} + 2HCl = MgCl_{2} + 2H_{2}O[/tex]
Then for finding the number of moles of magnesium hydroxide Mg(OH)[tex]_{2}[/tex]
number of moles = mass (grams) / molecular mass (g/mole)
number of moles of Mg(OH)[tex]_{2}[/tex] = 355 / 58 = 6.12
From the chemical reaction:
1 mole of Mg(OH)[tex]_{2}[/tex] reacts with 2 moles of HCl
6.12 moles of Mg(OH)[tex]_{2}[/tex] reacts with x moles of HCl
x = (6.12×2)/1 = 12.24 moles of HCl
And now we can determine the mass of hydrochloric acid HCl
mass (grams) = number of moles x molecular mass (grams/mole)
mass of HCl = 12.24 × 36.5 = 446.76 g
Final answer:
To determine the mass of hydrochloric acid needed to react with 355g of magnesium hydroxide, we use stoichiometry based on their molar masses to calculate that 444.09 grams of hydrochloric acid are required.
Explanation:
The student is asking how many grams of hydrochloric acid (HCl) are needed to fully react with 355g of magnesium hydroxide (Mg(OH)2). To solve this, we'll use the reaction equation:
Mg(OH)2 + 2HCl → MgCl2 + 2H2O
First, we need to find the molar mass of Mg(OH)2 (24.305 + 2(15.999) + 2(1.008) = 58.319 g/mol) and HCl (1.008 + 35.45 = 36.458 g/mol).
Next, we calculate the moles of Mg(OH)2 used using its molar mass:
355g Mg(OH)2 × (1 mol/58.319 g) = 6.09 mol Mg(OH)2
According to the balanced equation, 1 mole of Mg(OH)2 reacts with 2 moles of HCl. Thus:
6.09 mol Mg(OH)2 × (2 mol HCl/1 mol Mg(OH)2) = 12.18 mol HCl
Finally, we find the mass of HCl needed:
12.18 mol HCl × (36.458 g/mol) = 444.09 g HCl
Therefore, 444.09 grams of hydrochloric acid are needed to fully react with 355g of magnesium hydroxide.
If a liquid is sealed in a container and kept at constant temperature, how does its vapor pressure change over time?
It continues to steadily increase.
It increases at first, then remains constant.
It increases at first, then decreases.
It continues to steadily decrease.
Answer:
C. it will increase at first, then remain constant
Explanation:
PLEASE ANSWER Which is/are true?
[mark all correct
a. Li has valence electrons in the n = 1 energy level.
b. Si has valence electrons in the n = 3 energy level.
c. Ga has valence electrons in the n = 3 energy level.
d. Xe has valence electrons in the n = 5 energy level.
e. P has valence electrons in the n = 2 energy level.
You have to check each statement, so this is equivalent to 5 different questions.
Answers:
The true statements are:
b. Si has valence electrons in the n = 3 energy level.d. Xe has valence electrons in the n = 5 energy level.Explanations:
a. Li has valence electrons in the n = 1 energy level.
Answer: False.Valence electrons are the electrons in the outermost main energy level (shell of electrons).
To determine where the valence electrons are, you build the electron configuration, using Aufbau rules to predict the orbital filling: in increasing order of energy.
The atomic number of lithium (Li) is 3. Hence, you have to distribute 3 electrons, and so its electron confiuration is:
1s² 2s¹The only valence electron is in the 2s orbital, i.e. in the n = 2 energy level.
b. Si has valence electrons in the n = 3 energy level.
Answer: TrueSilicon (Si) has atomic number 14, so you have to distribute 14 electrons in increasing order of energy:
1s² 2s² 2p⁶ 3s² 3p²Thus, Si has five valence electrons, and they are in the n = 3 energy level.
c. Ga has valence electrons in the n = 3 energy level.
Answer: FalseGallium has atomic number 31, so you have to distribute 31 electrons, filling the orbitals in increasing order of enery.
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p¹The highest energy level is 4. This is where the valence electrons are. So, Ga has the valence electrons in the n = 4 level (not n = 3 as the statement describes).
d. Xe has valence electrons in the n = 5 energy level.
Answer: TrueThe atomic number of Xe is 54.
Using the short notation (noble gas notation), and filling the orbitals in increasing order of energy, you get the configuration:
[Kr] 5s² 4d¹⁰ 5p⁶.Hence, the valence electrons are in the n ) 5 level, such as the statement describes.
e. P has valence electrons in the n = 2 energy level.
Answer: FalsePhosphorus (P) has atomic number 15, hence there are 15 electrons.
The electron configuration following the increasing order of energy, which you can remember using Aufbau rules, is:
1s² 2s² 3s² 3p³Then, the valence electrons are in the n = 3 energy level; not in the n = 2 energy level.
A chemist has dissolved a certain substance in water. The chemist knows that more of the substance could be dissolved into the water before it stops dissolving. Therefore
Answer:
Therefore it has not become a saturated solution
Consider a sample of 10.0 g of the gaseous hydrocarbon C2H6 to answer the following question: How many moles are present in this sample?
When answering the question, include the following:
State how to find the molar mass for the hydrocarbon.
State how you know if you need to multiply or divide by the molar mass.
Give the correct number of significant figures and explain why the answer has that many significant figures.
Answer: The moles of given hydrocarbon is 0.3 moles
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
We are given:
Given mass of ethane = 10.0 g
Molar mass of ethane = [tex][(2\times 12)+(6\times 1)]=30g/mol[/tex]
We need to divide the given value by the molar mass.
Putting values in above equation, we get:
[tex]\text{Moles of ethane}=\frac{10.0g}{30g/mol}=0.3mol[/tex]
In case of multiplication and division, the number of significant digits is taken from the value which has least precise significant digits. Here, the least precise number of significant digits are 1.
Hence, the moles of given hydrocarbon is 0.3 moles
Final answer:
To find the number of moles of C₂H₆ in a 10.0 g sample, calculate the molar mass (30.0 g/mol) and divide the sample mass by the molar mass, resulting in approximately 0.333 moles. The answer has three significant figures, aligning with the initial mass provided.
Explanation:
To find the number of moles in a 10.0 g sample of C₂H₆, first, calculate the molar mass of C₂H₆. The molar mass is found by summing the atomic masses of all atoms in the molecule, which are 2 atoms of Carbon (C) and 6 atoms of Hydrogen (H). The atomic mass of Carbon is 12.0 g/mol and that of Hydrogen is 1.0 g/mol, resulting in a molar mass of 30.0 g/mol for C₂H₆.
To find the number of moles, you divide the mass of the sample by the molar mass of the compound. Therefore, divide 10.0 g by 30.0 g/mol, which equals approximately 0.333 moles of C₂H₆.
The answer, 0.333 moles, has three significant figures because the provided mass (10.0 g) has three significant digits. This is in accordance with the rule that the result of a division or multiplication operation in chemistry should have the same number of significant figures as the operand with the least number of significant figures.