Answer:
0.131 mol
Explanation:
there are 22.4 liters in a mol at STP so divide 2.94 by 22.4
Final answer:
To find the moles of carbon dioxide (CO₂) in 2.94 L at STP, one divides the volume of the gas by the molar volume of a gas at STP, which is 22.4 L/mol.
Explanation:
To calculate the number of moles of carbon dioxide gas (CO₂) at standard temperature and pressure (STP), we use the information that at STP, one mole of a gas occupies 22.4 liters. Thus, we can convert the given volume of carbon dioxide to moles using the following relationship:
Number of moles = Volume of gas at STP / Molar volume of gas at STP
The molar volume at STP is 22.4 L/mol. So for 2.94 L of CO₂, the calculation would be as follows:
Number of moles of CO₂ = 2.94 L / 22.4 L/mol
= 0.131 Moles
After performing the division, we will arrive at the 0.131 of moles, which represents the amount of carbon dioxide in the given volume at STP.
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.
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:
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.
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.
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⁺]
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×.
A dilute aqueous potassium nitrate solution is
Answer:
A dilute aqueous potassium nitrate solution is a homegeneous mixture.
Explanation:
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.
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.
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
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.
A pan containing 30 grams of water was allowed to cool from a temperature of 90.0 °C. If the amount of heat released is 1,500 joules, what is the approximate final temperature of the water?
A. 76 °C
B. 78 °C
C. 81 °C
D. 82 °C
Answer:
B. 78 °C.
Explanation:
To solve this problem, we can use the relation:Q = m.c.ΔT,
where, Q is the amount of heat released from water (Q = - 1500 J).
m is the mass of water (m = 30.0 g).
c is the specific heat capacity of water (c = 4.18 J/g.°C).
ΔT is the difference between the initial and final temperature (ΔT = final T - initial T = final T - 90.0 °C).
∴ (- 1500 J) = (30.0 g)(4.18 J/g.°C)(final T - 90.0 °C)
∴ (final T - 90.0 °C) = (- 1500 J)/(30.0 g)(4.18 J/g.°C) = - 11.96°C.
∴ final T = 90.0 °C - 11.96°C = 78.04°C ≅ 78 °C.
So, the right choice is: B. 78 °C.
Answer:
78 °C
Explanation:
I took the test and got it correct. hope this helps
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 ← answerConsider 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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The 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.
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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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
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.
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
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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The kw for water at 0 °c is 0.12× 10–14 m2. Calculate the ph of a neutral aqueous solution at 0 °c.
Answer:
pH = 7.46.
Explanation:
The ionization of water is given by the equation :H₂O(l) ⇄ H⁺(aq) + OH⁻(aq),
The equilibrium constant (Kw) expression is:
Kw = [H⁺][OH⁻] = 0.12 x 10⁻¹⁴.
in pure water and neutral aqueous solution, [H⁺] = [OH⁻]
So, Kw = [H⁺]²
∴ 0.12 x 10⁻¹⁴ = [H⁺]²
∴ [H⁺] = 3.4 x 10⁻⁸ M.
∵ pH = - log [H⁺]
pH = - log (3.4 x 10⁻⁸) = 7.46.
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.
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.
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:
In what kind of reaction do two or more substances combine to form a new compound
Answer:
Combination or synthesis
Explanation:
In combination or synthesis, there is formation of a single product from two or more reactants e.g:
H₂ + I₂ → 2HI
Here a compound forms from the association of the consituent elements.
Other kinds of chemical reactions we have are:
Decomposition or crackingSingle replacement or single displacementDouble replacement or double decomposition or metathesis.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
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.
Write an experiment to show that air exerts pressure in all directions
Answer:
Experiment: Submit a can or plastic bottle with hot, sealed air to a sudden cooling and watch what happens.Explanation:
Air is a mixture of gases (mainly oxygen and nitrogen, but also carbon dioxide, water vapor, and others in minimum amount).
The pressure of the gases is the product of the collisions of the air molecules with the surface of the objects. Since the molecules of gases are in constant, rapid random motion, they are constantly (you may say continously) colliding with the surfaces of the objects in all directions. That explain, why the air exertes pressure in all directions.
There are many experiments that you can perform to show this phenomenum.
You can perform this experiment, for example:
Take an "empty" can or plastic bottle, which you can heat using a source of hot water. You can do this by introducing the can or plastic bottle inside a pan with hot water, avoiding that the water enters into the your object.Once the air inside the can or plastic bottle is hot, remove it from the pan and close it, so that air cannot exit from of enter into it.Pour cold water over the can or plastic.What will you observe?
The can or plastic bottle will collapse.Why does that happen?
Because, when you pour cold water over the can or plastic bottle the air inside will cool down, and as result the air inside it will exert less pressure over the inner walls than the pressure that the air ouside it exerts over the outer walls.Since the pressure is exerted in all the directions, the bottle or can collapse.
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.