three examples of physical chemistry from our surroundings?
Answer:
Burning of paper and log of wood.
Digestion of food.
Boiling an egg.
Explanation:
Which phase has the lowest entropy?
O A. Aqueous
O B. Liquid
O C. Solid
O D. Gas
Answer:
Solid have the lowest entropy
Consider the following representation of a reaction mechanism.
Step 1: A+ AC + E (slow)
Step 2: E+BA+ D (fast)
Overall reaction: A + B C + D
→>>
What should appear in the rate law for the reaction above?
O only A and B because they are reactants in the overall reaction
only C and C because they are products in the overall reaction
only A because it is the reactant in the rate-determining step
O only E and B because they are the reactants in the rate-determining step
The rate law depends on only A because it is the reactant in the rate-determining step.
What is the rate law;The rate law is a representation of the rate of reaction. The fast reaction is E+B ------> A+ D. The slow reaction is A + A ----->C + E. The overall reaction is A + B ------> C + D.
We know that the rate law depends only on the the slow reaction hence the rate law depends on only A because it is the reactant in the rate-determining step.
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- If x moles of electrons are transferred when 4.8 g of oxygen reacts with 4.8 g of
magnesium, what is the value of x?
Answer:
sdfffffffff
Explanation:
dfffffgsdsdsdsdsdsdsdsdsdsdsdsdsdsdsd
how to explode stuff
describe a weather station that will be used to collect weather data it should collect data that are needed to make forecasts. explain what data are needed how the station would be powered and any other relevant information . Then sketch it out
(please draw a sketch arigato)
The weather station is a place which contain instrument that collect data of atmospheric pressure, wind, humidity, etc to forecast weather. The weather station is powered by solar power.
What is a weather station?A weather station is a place that measure atmospheric conditions, on the basis of temp., pressure, wind speed, etc conditions.
They can be based either in land or sea. They are necessary to forecast any disaster, so we can prepare for the disaster.
Thus, the weather station is a place which contain instrument that collect data of atmospheric pressure, wind, humidity, etc to forecast weather. The weather station is powered by solar power.
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A certain atom has 22 protons and 19 electrons. This atom loses an electron. The net charge on the atom is now 4+. If this same atom with 22 protons and 19 electrons were to gain 3 electrons, the net charge on the atom would be
Answer: 0
Explanation:
If 3 electrons were to be gained, then the number of protons would equal the number of electrons.
of an investigation, students were asked to prepare a sodium hydroxide solution of a certain molarity. The students were given a
of procedures. Which procedure will result in 750 mL of 1.5 M NaOH solution?
issolving 1.13 g of NaOH in enough water to make up to 750 mL of solution
ssolving 45 g of NaOH in enough water to make up to 750 mL of solution
ssolving 40 g of NaOH in 1 L of water
solving 1.13 g of NaOH in 0.750 L of water
The correct procedure is:
Dissolving 45 g of NaOH in enough water to make up to 750 mL of solution
What is molarity?This is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:
Molarity = mole / Volume
How to determine the mole of NaOH Volume = 750 mL = 750 / 1000 = 0.75 L Molarity = 1.5 MMole of NaOH =?Mole = Molarity x Volume
Mole of NaOH = 1.5 × 0.75
Mole of NaOH = 1.125 mole
How to determine the mass of NaOH Mole of NaOH = 1.125 moleMolar mass of NaOH = 40 g/mol Mass of NaOH =?Mass = mole × molar mass
Mass of NaOH = 1.125 × 40
Mass of NaOH = 45 g
Thus, to obtain 750 mL of 1.5 M NaOH solution, 45 g of NaOH will be dissolved in enough water to make up to 750 mL of solution
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Which statement best describes what makes a base weak
The statement that describes what makes a base weak is that the base will be unable to dissociate completely in water.
What is a base?A base is any of a class of generally water-soluble compounds, having bitter taste, that turn red litmus blue, and react with acids to form salts.
Bases usually dissociate into hydroxide ions (OH-) when in an aqueous solution.
However, a base is termed weak or strong depending on it's ability to dissociate completely. A weak base does not dissociate completely into hydroxide ions when in an aqueous solution.
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Which is an unreliable source?
A scientist who studies dinosaurs presents her research on velociraptors at a science convention.
An advertisement for acne medication claims it can clear up acne in less than one week.
An article on the Centers for Disease Control and Prevention (CDC) website discusses the salmonella bacteria.
A chemistry teacher discusses possible projects for the upcoming science fair.
The source that is unreliable is an advertisement for acne medication claims it can clear up acne in less than one week.
What are citable sources?Citable sources are those sources that are gotten from places that are proven to be of good standards and not from mere claims such as:
Science journalsprofessional organizationsgovernment agenciesTherefore, the source that is unreliable is an advertisement for acne medication claims it can clear up acne in less than one week.
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How many grams do 6.534e+24 molecules of phosphoric acid weigh?
Answer:
1,063 grams H₃PO₄
Explanation:
To find the mass of phosphoric acid (H₃PO₄), you should (1) convert molecules to moles (via Avogadro's number) and then (2) convert moles to grams (via molar mass from periodic table).
Molar Mass (H₃PO₄): 3(1.008 g/mol) + 30.974 g/mol + 4(15.998 g/mol)
Molar Mas (H₃PO₄): 97.99 g/mol
6.534 x 10²⁴ molecules H₃PO₄ 1 mole 97.99 g
--------------------------------------------- x ------------------------------------- x --------------
6.022 x 10²³ molecules 1 mole
= 1,063 grams H₃PO₄
Based on reference table G what is the maximum number of grams of KCI(s) that will dissolve in 200 grams of water at 50•c to produce a saturated solution
About 80g of KCl will dissolve in 200g of water at 50 degrees.
What is a saturated solution?A saturated solution contains just as must solute as it can normally hold at a given temperature.
Looking at the table we can see that about 40 g of KCl dissolves in 100 g of water at 50 degrees hence about 80g of KCl will dissolve in 200g of water at 50 degrees.
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show the step by step hybridization of hydroxonium ion H3O, draw the diagram showing the geometry and the bond angle
The central oxygen atom is a state of sp3 hybridization having only one available lone pair.
What is hybridization?The term hybridization refers to the mixing of two or more atomic orbitals to yield hybrid orbitals that are suitable for bonding.
Looking at the ion H3O^+, we can see that the central oxygen atom is a state of sp3 hybridization having only one available lone pair. The image of the ion is shown here.
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(5 pts) Calculating Heat from Thermochemical Equations
The thermochemical equation for the combustion of methane gas is:
Calculate much heat is released when 3.5 moles of methane gas undergo a combustion reaction.
The heat that is released by the combustion of 3.5 moles of methane is 3115 kJ/mol.
What is a thermochemical equation?A thermochemical equation is a reaction equation that incorporates the amount of heat lost/gained.
In this case, the reaction equation is; CH4 + O2 ----->CO2 + 2H2O dH = -890 kJ/mol
If 1 mole of methane releases 890 kJ/mol
3.5 moles of methane will release 3.5 moles * 890 kJ/mol/1 mole
= 3115 kJ/mol
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All else being equal, air volume increases when pressure decreases. Use this relationship to explain why warm air at the equator rises up through the less dense air above it.
The relation between the volume and the pressure of the gas can be given by the ideal gas equation. Warm air has more volume and low pressure that makes them rise above the equator.
What is atmospheric pressure?Pressure present and exerted by the atmospheric gases are called atmospheric pressure. The volume of the gas is in inverse relation to the pressure of the gas.
Warm air has a high volume compared to cold air. More volume results in low pressure making them rise above the dense layer of the equator region.
Therefore, the warm air rises due to a decrease in pressure.
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noltoupe sonblod
Example: Ksp for cadmium carbonate is 1.8 * 10-14, calculate
the equilibrium solubility of cadmium carbonate in a solution at
constant pH of 11?
For H₂CO3
1- Ka = 4.45 * 10-7
2-ka =4.7*10-11
The equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is 1.65 x 10⁻⁵ mol/dm³.
Equilibrium solubility of the compound
The equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is calculated as follows;
H₂CO3 ⇄ 2H⁺ + CO₃²⁻
x : 2x x
ksp = (2x)²x
ksp = 4x³
(1.8 x 10⁻¹⁴) = 4x³
(1.8 x 10⁻¹⁴) /4 = x³
4.5 x 10⁻¹⁵ = x³
x = (4.5 x 10⁻¹⁵)^¹/₃
x = 1.65 x 10⁻⁵ mol/dm³
Thus, the equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is 1.65 x 10⁻⁵ mol/dm³.
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The equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is 1.65 x 10⁻⁵ mol/dm³.
What is solubility?Solubility is defined as the maximum amount of a substance that will dissolve in a given amount of solvent at a specified temperature.
The equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is calculated as follows;
H₂CO3 ⇄ 2H⁺ + CO₃²⁻
x : 2x x
ksp = (2x)²x
ksp = 4x³
(1.8 x 10⁻¹⁴) = 4x³
(1.8 x 10⁻¹⁴) /4 = x³
4.5 x 10⁻¹⁵ = x³
x = [tex](4.5 X 10^{-15})^{\frac{1}{3} }[/tex]
x = 1.65 x 10⁻⁵ mol/dm³
Thus, the equilibrium solubility of cadmium carbonate in a solution at constant pH of 11 is 1.65 x 10⁻⁵ mol/dm³.
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How many moles of water (H2O) does 10.82 x 1023 molecules represent? Round your answer to the hundredths place.
No of moles
[tex]\\ \rm\Rrightarrow \dfrac{No\:of\: molecules}{Avagadro\:no}[/tex]
[tex]\\ \rm\Rrightarrow \dfrac{10.82\times 10^{23}}{6.023\times 10^{23}}[/tex]
[tex]\\ \rm\Rrightarrow 1.80mol[/tex]
So
[tex]\boxed{\sf No\:of\: molecules=No\:of\:moles\times Avagadro\:no}[/tex]
[tex]\\ \tt{:}\longrightarrow 10.82\times 10^{23}=n\times 6.023\times 10^{23}[/tex]
[tex]\\ \tt{:}\longrightarrow n=\dfrac{10.82}{6.023}[/tex]
[tex]\\ \tt{:}\longrightarrow n=1.8mol[/tex]
1 When a piece of sodium metal is dropped into water, hydrogen gas is released leaving a
solution of sodium hydroxide.
(a) Write a balanced equation for this reaction.
(b) Calculate the mass of hydrogen gas released when 43.9 g of sodium reacts.
Answer:
When sodium metal is dropped in water, hydrogen gas is evolved. Thus, the reaction is, 2Na+2H2O→H2+2NaOH. In the reaction, sodium hydroxide is formed and hydrogen gas is evolved.
Explanation:
Find the pressure in mm HG produced by 2.35 g of carbon dioxide in a 5.00 L flask at 18 C?
Answer:
194 mm Hg or 193.8mm Hg
Explanation:
273+18=291 K
2.35g /44
=0.0534 moles
P=0.0534 mol×0.082×29 / 5L
=0.2548 atm
0.255 × 760
=193.8 mmHg
How many moles of MgCl2 where needed to make a 650.0 mL solution a concentration of 0.962 M?
Answer:
0.625 moles MgCl₂
Explanation:
Since you were given a molarity value and volume, you should use the molarity equation to find moles. The equation looks like this:
Molarity (M) = moles / volume (L)
To find moles, you need to (1) convert mL to L (by dividing by 1,000) and then (2) plug the numbers into the formula and simplify to find moles. The final answer should have 3 sig figs as the lowest amount of sig figs in a given value is 3.
Step 1:
650.0 mL / 1,000 = 0.6500 L
Step 2:
Molarity = moles / volume
0.962 M = moles / 0.6500 L
(0.962 M) x (0.6500 L) = moles
0.625 = moles
Question 5 of 20:
Select the best answer for the question.
5. When considering gravity acceleration and the force of acceleration, what must be true?
O A. The direction of acceleration must be perpendicular to the direction of the force.
O B. The direction of the force and the direction of acceleration must be opposite of each other.
OC. The direction of the force and the direction of acceleration must be the same as each other.
O D. The mass of the body must be the same as the acceleration of the body.
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Convert 26.02 x 1023 molecules of C2H8 to grams. Round your answer to the hundredths place.
No of molecules=26.02×10²³molecules
No of moles
26.02×10²³/6.023×10²³4.3molMolar mass
C2H82(12)+8(1)24+832g/molMass
Moles×Molar mass32(4.3)137.6g[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{Molecules}{Avagadro\:no}[/tex]
[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{26.02\times 10^{23}}{6.023\times 10^{23}}[/tex]
[tex]\\ \tt{:}\longrightarrow No\:of\:moles=4.32mol[/tex]
Molar mass of Ethane=32g/molWe need the mass
[tex]\\ \tt{:}\longrightarrow No\:of\:moles\times molar\:mass[/tex]
[tex]\\ \tt{:}\longrightarrow 32(4.32)[/tex]
[tex]\\ \tt{:}\longrightarrow 138.24g[/tex]
If you dissolve 25.0 g of NaNO3 (Mm = 85.0 g) in 155 mL of water, what is the molarity of the solution? (Report your answer to two places past the decimal point)
Answer:
1.90 M
Explanation:
To find the molarity of the solution, you need to use the molarity equation. This formula looks like this:
Molarity (M) = moles / volume (L)
To use this equation, you need to perform some conversions. You should (1) convert mL to L (by dividing by 1,000), then (2) convert grams NaNO₃ to moles (via molar mass), then (3) plug moles and volume into the molarity equation.
155 mL / 1,000 = 0.155 L
25.0 g NaNO₃ 1 mole
--------------------- x ----------------- = 0.294 moles NaNO₃
85.0 g
Molarity = moles / volume
Molarity = 0.294 moles / 0.155 L
Molarity = 1.8975....
Molarity = 1.90 M
Question 11 of 30
During a reaction, the enthalpy of formation of an intermediate is -286
kJ/mol. During the reaction, 2 moles of the intermediate are produced. What
is the enthalpy value for this step of the reaction?
O A. -286 kJ
B. 572 kJ
OC. 286 kJ
OD. -572 kJ
By convention, the standard enthalpy of formation of all elements in their standard states are assumed to be zero. Here the enthalpy value for the intermediate formation step is -572 kJ. The correct option is D.
What is enthalpy of formation?The standard enthalpy of formation of a compound is defined as the enthalpy change accompanying the formation of one mole of the compound from its constituent elements, all the substances being in their standard states.
The symbol used to represent the standard enthalpy of formation is ΔfH⁰. The knowledge of standard enthalpies of various substances is useful for calculating the standard enthalpies of a reaction.
The overall energy difference between the reactants and products remains the same no matter how many intermediates there are in the reaction pathway.
The enthalpy value = 2 × -286 = -572 kJ
Thus the correct option is D.
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Temperature Change Curing Phase Change (5 pts)
Water boils at 100 °C. You boil a pot containing 500 g of water for 10 minutes.
What is the temperature of the water after 10 minutes of constant boiling? (Hint this question does not require any math).
Explain your answer by discussing heat and state change.
Answer:
since water boil at 100 °C .so 500gof water Will still boil at 100 °C
3) Convert 0.987 moles of Lithium to grams.
Answer:
6.850767 grams is the answer
[tex]0.987 ~ \text{moles of Li} = 0.987 \times \text{Molar mass of Li}\\\\~~~~~~~~~~~~~~~~~~~~~~~=0.987 \times 6.941~ g\\\\~~~~~~~~~~~~~~~~~~~~~~~=6.850767~ g[/tex]
Why would you use a solution, such as a cabbage ph indicator, to measure the ph of household items?.
Answer:
Discussion: Red cabbage is useful as a pH indicator because the leaves contain a pigment molecule from the family of anthocyanins (shown below) which are responsible for many of the red/purple/blue colors observed in fruits and vegetables. In neutral solutions, the color observed is purple.
hope this helps:3
Analyze the word problem and match the vocabulary terms to the chemicals in the word problem.
5.00 grams of solid citric acid is dissolved in 500.00 ml of water to make aqueous citric acid
5.00 grams of solid citric acid (solute) is dissolved in 500.00 ml of water (solvent) to make aqueous citric acid (solution).
What is a solution?A solution is a homogeneous mixture prepared by dissolving a solute in a solvent.
5.00 grams of solid citric acid is dissolved in 500.00 ml of water to make aqueous citric acid.
In this example:
5.00 grams of solid citric acid is the solute (what is dissolved).500.00 ml of water is the solvent (the media in which the solute is dissolved).Aqueous citric acid is the resulting solution.5.00 grams of solid citric acid (solute) is dissolved in 500.00 ml of water (solvent) to make aqueous citric acid (solution).
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Calculate 5.1234 + 0.033÷ 1.650 and report to the correct number of significant figures.
5.1434 contains 5 significant figures and 4 decimals.
What is a significant figure?All zeros that occur between any two non-zero digits are significant. For example, 108.0097 contains seven significant digits.
Calculation:
5.1234 + 0.033÷ 1.650 = 5.1434
5.1434 contains 5 significant figures and 4 decimals. 5.1434 rounded to 4 sig figs is 5.143, to 3 sig figs is 5.14, and to 2 sig figs is 5.1.
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Why do you think it is
important to group substances and mixtures based on their classifications or uses?
The purpose of classification is to identify objects with common or similar properties.
What is a mixture?A mixture is composed of one or more pure substances in varying compositions.
It's important for scientists to know the properties of matter because all things are made up of matter.
Each type of matter has different physical characteristics and scientists need to know and understand these characteristics to make calculations.
The main phases of matter are solid liquid and gas.
Hence, the purpose of classification is to identify objects with common or similar properties.
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