Air resistance opposes the gravity in a falling object hence the object loses speed once it reaches terminal velocity.
According to the experiment of Galileo, in the absence of air resistance, all objects that are thrown down from the same height will hit the ground at he same time due to the effect of gravity.
We know that the air resistance makes the acceleration of object to become less than the acceleration due to gravity. So, air resistance opposes the force of gravity and causes falling objects to lose speed once they reach terminal velocity.
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Answer:
The answer is D - Air resistance opposes the force of gravity and causes falling objects to lose speed once they reach terminal velocity.
Ill explain why -, for example ,
When the paper is smooth, it exposes a large surface to the air beneath it which slows its descent. Once it is crumpled, the surface which comes in contact with the air is much smaller, allowing it to fall much faster. At first, you probably thought the book would touch the ground first since it is heavier However, once the piece of paper was crumpled, they hit the ground at the same time! Funny, since it is the same piece of paper and the book is still heavier. It all comes down to form. I hope this helped u with the test !!
Dissolution of KOH, ΔHsoln:
KOH(s) → KOH(aq) (10.1)
Neutralization of solid KOH, ΔHneut:
KOH(s) + HCl(aq) → H2O(l) + KCl(aq) (10.2)
1) Using Hess's law, show how to combine Reaction 10.1 and Reaction 10.2 to give
KOH(aq) + HCl(aq) → H2O(l) + KCl(aq) (10.3)
2)How should ΔHsoln and ΔHneut be combined (mathematically) to give the change in enthalpy for Reaction 10.3, ΔH?
Using Hess's law we found:
1) By adding reaction 10.2 with the reverse of reaction 10.1 we get reaction 10.3:
KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) ΔH (10.3)
2) The ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy (ΔH).
The reactions of dissolution (10.1) and neutralization (10.2) are:
KOH(s) → KOH(aq) ΔHsoln (10.1)
KOH(s) + HCl(aq) → H₂O(l) + KCl(aq) ΔHneut (10.2)
1) According to Hess's law, the total change in enthalpy of a reaction resulting from differents changes in various reactions can be calculated as the sum of all the enthalpies of all those reactions.
Hence, to get reaction 10.3:
KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) (10.3)
We need to add reaction 10.2 to the reverse of reaction 10.1
KOH(s) + HCl(aq) + KOH(aq) → H₂O(l) + KCl(aq) + KOH(s)
Canceling the KOH(s) from both sides, we get reaction 10.3:
KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq) (10.3)
2) The change in enthalpy for reaction 10.3 can be calculated as the sum of the enthalpies ΔHsoln and ΔHneut:
[tex] \Delta H = \Delta H_{soln} + \Delta H_{neut} [/tex]
The enthalpy of reaction 10.1 (ΔHsoln) changed its sign when we reversed reaction 10.1, so:
[tex] \Delta H = \Delta H_{neut} - \Delta H_{soln} [/tex]
Therefore, the ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy ΔH.
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What is the [H+] if pOH =9.50
will it be acid or basic?
Taking into account the definition of pH and pOH, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.
First of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.
The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:
pH= - log [H⁺]= - log [H₃O⁺]
Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:
pOH= - log [OH⁻]
The following relationship can be established between pH and pOH:
pH + pOH= 14
In this case, being pOH= 9.50, pH is calculated as:
pH + 9.40= 14
pH= 14 - 9.50
pH= 4.50
Replacing in the definition of pH the concentration of H⁺ ions is obtained:
- log [H⁺]= 4.50
Solving :
[H⁺]= 10⁻⁴ ⁵
[H⁺]= 3.16×10⁻⁵ M
The numerical scale that measures the pH of the substances includes the numbers from 0 to 14, being acidic solutions with a pH lower than 7, and basic those with a pH greater than 7. The pH = 7 indicates the neutrality of the solution.
In this case, the pH has a value of 4.50. So, the solution is acidic.
In summary, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.
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brainly.com/question/16032912?referrer=searchResults brainly.com/question/13557815?referrer=searchResultsGrace wanted to find out the best conditions for growing lettuce plants.
She took 4 trays and planted 8 lettuce plants in each.
The results of her investigation are shown below.
How many days did the investigation last?
Use the table to help you.
Explanation:
the investigation lasts for 7 days.
hope this helps you.
Fill in the left side of this equilibrium constant equation for the reaction of benzoic acid with water
Answer:
C6H5CO2H (aq) + H2O (l) _C6H5CO2- + H3OWhat are the dependent and independent variables in this experiment? How are outside factors being controlled in this experiment to make sure that the results test only the dependent variable?
Answer:
1. An independent variable is manipulated, or changed. The dependent, or responding variable, changes based on the independent variable. The dependent variable is examined.
2. It is a controlled experiment.
Explanation:
In a controlled experiment all variables are kept the same, except for the one being tested, which is called the experimental variable , or independent variable . This group is the experimental group . The group that is not affected by the experimental variable is the control group .
Very often a graph will be used to analyze the results of the experiment. The independent/experimental variable is placed on the x-axis and the dependent variable is placed on the y-axis. The dependent variable is what is measured as a result of the application of the experimental variable.
A variable that is independent is altered. Based on the independent variable, the responding variable, or dependent variable, alters. Examining the dependent variable. The experiment is carefully controlled.
What is an independent variable ?In mathematical modeling, statistical modeling, and experimental sciences, there are dependent and independent variables. Dependent variables get their name because, during an experiment, their values are investigated under the presumption or requirement that they are dependent on the values of other variables due to some law or rule.
A variable that is independent is precisely what it sounds like. It is a stand-alone variable that is unaffected by the other variables you are attempting to assess. Age, for instance, could be an independent variable.
When doing an experiment, the independent variable is what you alter, and the dependent variable is what changes as a result of that change. This is an easy way to conceive of independent and dependent variables.
Thus, based on the independent variable, the responding variable, or dependent variable, alters.
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In the following reaction, what is the quantity of heat (in kJ) released when 5.87 moles of CH₄ are burned?
CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O(g) ∆H° = -802 kJ/mol
Taking into account the definition of enthalpy of a chemical reaction, the quantity of heat released when 5.87 moles of CH₄ are burned is 4,707.74 kJ.
The enthalpy of a chemical reaction as the heat absorbed or released in a chemical reaction when it occurs at constant pressure. That is, the heat of reaction is the energy that is released or absorbed when chemicals are transformed into a chemical reaction.
The enthalpy is an extensive property, that is, it depends on the amount of matter present.
In this case, the balanced reaction is:
CH₄ (g) + 2 O₂ (g) → CO₂ (g) + 2 H₂O(g)
and the enthalpy reaction ∆H° has a value of -802 kJ/mol.
This equation indicates that when 1 mole of CH₄ reacts with 2 moles of O2, 802 kJ of heat is released.
When 5.87 moles of CH₄ are burned, then you can apply the following rule of three: if 1 mole of CH₄ releases 802 kJ of heat, 5.87 moles of CH₄ releases how much heat?
[tex]heat=\frac{5.87 molesof CH_{4}x802 kJ}{1 mol of CH_{4} }[/tex]
heat= 4,707.74 kJ
Finally, the quantity of heat released when 5.87 moles of CH₄ are burned is 4,707.74 kJ.
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Yes according to reliable sources.
which two types of food are homogeneous mixtures
A. mustard
B. mayonnaise
C. tossed salad
D. trail mix
In the laboratory you are asked to make a 0.282 m manganese(II) acetate solution using 315 grams of water. How many grams of manganese(II) acetate should you add
Answer:315 - 282 = 173?
Explanation:
what is the best way to make a supersaturated solution?
A: Heat the solution
B: Stir the Solution
C: Evaporate the solution
D: Cool the solution
Answer:
heat the solution
Explanation:
i think
Answer:
The way to make a supersaturated solution is to add heat, but just a little heat won't do the job. You have to heat the water close to the boiling point. When the water gets this hot, the water molecules have more freedom to move around, and there is more space for solute molecules between them.
How is hot spot and ring of fire similar
Answer:The plates are not fixed but are constantly moving atop a layer of solid and molten rock called the mantle. The Ring of Fire is a string of volcanoes and sites of seismic activity, or earthquakes, around the edges of the Pacific Ocean. ... A hotspot is a place in the middle of a tectonic plate where hot magma rises.
Explanation:
Identify the strongest intermolecular force that is likely to affect each of the samples described below.
A mixture of chlorine gas (Cl) and fluorine gas (F): V London dispersion forces
COMPLETE
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A mixture of hydrogen sulfide (H2S) and hydrogen chloride (HCI): V dipole-dipole interactions
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Selection
COMPLETE
Guess
this
hydrogen bonding
A mixture of water (H2O) and ammonia (NH3):
Answer:
A mixture of chlorine gas (Cl2) and fluorine gas (F2):
✔ London dispersion forces
Explanation:
Calcium has an electronegativity value of 1.0.
Oxygen has an electronegativity value of 3.5.
What type of bond will form between the two atoms?
Answer:
ionic bond
Explanation:
Calcium gives its two valence electrons to oxygen and forms an ionic bond with oxygen. An ionic bond formed when one atom transfers one or more electrons from itself to its neighboring atom, and an ionic bond formed between the two atoms of the compound.
a. Calculate the change in enthalpy when 20.0 grams of aluminum metal is heated from 298 K to 573 K at constant pressure of 1 atm.
b. Calculate the change in enthalpy when 20.0 grams of metallic lead is taken through the same process. In both cases assume the heat capacity values predicted by equipartition are valid through the temperature range stated.
A car is traveling 70km in 45 minutes. How many miles an hour is the car traveling?
52
Explanation:
70x45÷60= 52
I hope this is helpful
Construct a conclusion using the claim, evidence and reasoning format to explain the typical properties observed by ionic and covalent compounds.
Answer:
The key to understanding why ionic and covalent compounds have different properties from each other is understanding what's going on with the electrons in a compound. Ionic bonds form when atoms have different electronegativity values from each other. When the electronegativity values are comparable, covalent bonds form.
But, what does this mean? Electronegativity is a measure of how easily an atom attracts bonding electrons. If two atoms attract electrons more or less equally, they share the electrons. Sharing electrons results in less polarity or inequality of charge distribution. In contrast, if one atom attracts bonding electrons more strongly than the other, the bond is polar.
Ionic compounds dissolve in polar solvents (like water), stack neatly on each other to form crystals, and require a lot of energy for their chemical bonds to break. Covalent compounds can be either polar or nonpolar, but they contain weaker bonds than ionic compounds because they are sharing electrons. So, their melting and boiling points are lower and they are softer.
I hope this helps have a great day :)
The melting point of H₂O(s) is 0 °C. Would you expect the melting point of H₂S(s) to be 85 °C, 0 °C or -85 °C.? Justify your choice
Answer:
-85 °C
Explanation:
O and S are in the same group( Group 16). Since S is below O it's atomic mass is higher than O. So molar mass of H2S is higher than H2O. The strength of Vanderwaal Interactions ( London dispersion forces) increases when the molar mass increases. However, only H2O can form H bonds with each other. This is because electronegativity of O is higher than S and therefore H in H2O has a higher partial positive charge than H of H2S.
H bond dominate among these 2 types of forces so the strength of attractions between molecules is higher in H2O than H2S. Therefore more energy should be supplied for H2O to break inter
molecular forces and convert from solid to liquid state than H2S. So mpt of H2O must be higher than that of H2S.
Find five household items that contain ionic compounds. List the following information for each compound: a.name of the product
b. the chemical name of the ionic compound
d.the chemical formula of the ionic compound c. identify the ions present in each compound
Answer:
D . GOD BLESS .
Explanation:
an alloy composed of tin, lead, and cadmium is analyzed. the mole ratio of sn:pb is 2.73:1.00, and the mass ratio of pb:cd is 1.78:1.00. what is the mass percent composition of pb in the alloy
This problem is describe the mole-ratio composition of an allow composed by tin, lead and cadmium. Ratios are given as Sn:Pb 2.73:1.00 and Pb:Cd is 1.78:1.00, and we are asked to calculate the mass percent compositon of Pb in the allow.
In this case, according to the given information, it turns out possible realize that the following number of moles are present in the alloy, according to the aforementioned ratios:
[tex]2.73mol Sn\\\\1.00molPb\\\\\frac{1.00molPb*1.00molCd}{1.78molPb}= 0.562molCd[/tex]
Next, we calculate the masses by using each metal's atomic mass:
[tex]m_{Sn}=2.73mol*\frac{118.7g}{1mol}=324.05g\\\\ m_{Pb}=1.00mol*\frac{207.2g}{1mol}=207.2g\\\\m_{Cd}=0.562mol*\frac{112.4g}{1mol}=63.2g[/tex]
Thus, the mass percent composition of each metal is shown below:
[tex]\%Sn=\frac{324.05g}{324.05g+207.2g+63.2g} *100\%=54.5\%\\\\\%Pb=\frac{207.2g}{324.05g+207.2g+63.2g} *100\%=34.9\%\\\\\%Cd=\frac{63.2}{324.05g+207.2g+63.2g} *100\%=10.6\%[/tex]
So that of lead is 34.9 %.
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Environmental scientists collect air samples so they can test the quality of the air. They start with rigid metal containers that are completely empty—the air has been pumped out of them.
What happens to the pressure inside the container and the volume of the container as air enters it?
Explanation:
filling air inside an empty o2 medal containers, if air is added, the air inside, creates volume inside.
due to heat, weather,... depending on what indoor or outdoor storage said containers r placed in,;
So, I can't give you an answer, due to lack of details..sorry...
Which statement best describes the effect of radioactive decay on a nucleus?
When radioactive decay occurs, the original nucleus splits into daughter nuclei and the resulting nucleus is more stable than the original nucleus. The nucleus can be of a different element than the original.
Unstable nuclei often undergo radioactive decay. In a radioactive decay, the unstable nucleus is broken up into other nuclei. Usually, the nuclei formed during radioactive decay are smaller in mass compared to the original nucleus.
Also, the resulting nucleus is more stable than the original nucleus. The nucleus can be of a different element than the original.
The effect is that the nucleus changes into the nucleus of one or more other elements. These daughter nuclei have a lower mass and are more stable (lower in energy) than the parent nucleus.
classify each of the statements about gases as true or false. oxygen molecules at 25 celsius are moving faster than oxygen
Since gas molecules average velocity depends on temperature, oxygen molecules at 25°C are moving faster than oxygen molecules at 0 °C.
According to the kinetic theory of gases, the molecules of a gas are in constant random motion and collide frequently with each other and the walls of the container.
The average speed of gas molecules depends on temperature and molar mass as shown by the relation;
vrms = √3RT/M
The following statement are true among the options provided;
Oxygen molecules at 25°C are moving faster than oxygen molecules at 0 °C Gases exert pressure by colliding with container wallsThe following are false among the options provided;
All hydrogen molecules are moving with the same velocityNitrogen gas exerts more pressure than hydrogen gas because nitrogen molecules are heavier than hydrogen molecules. Nitrogen molecules remain suspended in the atmosphere because they are not attracted to Earth by gravitational forces.Learn more: https://brainly.com/question/6505878
as the solar nebula cooled which compounds were the first to condense from a gas to a solid? Rock water ice or metal
As the solar nebula cooled METAL compounds are the first to condense from a gas to a solid. The solar nebula gave birth to the Solar system.
A solar nebula is a disc-shaped cloud of gases and grain dust, which gave birth to the Sun and planets of the Solar system, approximately 4.6 billion years ago.
The solar nebula is at the beginning a mixture of interstellar gases (hydrogen and helium) and dust grains.
As the solar nebula cools, heavy elements such as metals in the disk condensate into planetesimals.
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Which of the following best describes the scientific exploration of the atom?
A gas has a volume of 3.7 liters with a pressure of 1.75 atm. What is the pressure of the gas if its volume is raised to 4.5 L?
Answer: 251 K
Explanation: hope this helps :)
Why are sound waves considered a type of mechanical energy?
Question 6 options:
Sound waves can travel through space
Sound waves can travel through a solid
Sound waves transfer energy by the motion of particles
Sounds waves are made by machines
-Sound waves transfer energy by the motion of particles.
Explanation:
These particle-to-particle, mechanical vibrations of sound conductance qualify sound waves as mechanical waves. Sound energy, or energy associated with the vibrations created by a vibrating source, requires a medium to travel, which makes sound energy a mechanical wave.
Sound waves transfer energy by the motion of particles considered a type of mechanical energy.
What is mechanical energy ?Potential energy plus kinetic energy are combined to form mechanical energy. According to the concept of mechanical energy conservation, mechanical energy remains constant in an isolated system that is solely exposed to conservative forces.
The quantity of energy that a force transfers is known as mechanical work. It is a scalar quantity with joules as its SI unit, much as energy.
Since there are only microscopic forces generated by atomic collisions and no macroscopically quantifiable force, heat conduction is not regarded as a kind of work.
Transverse, longitudinal, and surface waves are the three different forms of mechanical waves. When the wave's energy goes through them, they behave differently in terms of how the medium's particles move.
Thus, option C is correct.
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How many atoms are in mercury (I) phospate?
The chemical formula is (Hg2)3(PO4)2
A)11
B)14
C)15
D)16
Mercury (I) phosphate with the chemical formula (Hg2)3(PO4)2 has 16 atoms.
Number of Hg atoms = 2x3 = 6Number of P atoms = 2 x 1 = 2Number of O atoms = 4x2 = 8Sum of all the atoms = 6+2+8
= 16 atoms
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Calculate the mass (in grams) of chlorine (Cl2) gas sample which occupies a 2.50 L container at a pressure of 1.22 atm and temperature of 27.8°C?
Answer:Nothing
Explanation:
The answer is nothing the tempatature isnt matched with the degrees this is false
Determine the molarity for each of the following Solution: 98.0 of phosphoric acids H3PO4 in 1.00L of Solution.
The molarity of the solution is 0.01.
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Find the volume of 0.170 M sulfuric acid necessary to react completely with 72.2 g sodium hydroxide.
The volume of sulphuric acid, H₂SO₄ needed for the complete reaction with 72.2 g of sodium hydroxide, NaOH is 5.31 L
We'll begin by calculating the number of mole in 72.2 g of NaOH. This can be obtained as follow:
Mass of NaOH = 72.2 g
Molar mass of NaOH = 23 + 16 + 1 = 40 g/mol
Mole of NaOH =?Mole = mass / molar mass
Mole of NaOH = 72.2 / 40
Mole of NaOH = 1.805 mole Next, we shall determine the number of mole of H₂SO₄ needed to react with 1.805 mole of NaOH.2NaOH + H₂SO₄ —> Na₂SO₄ + 2H₂O
From the balanced equation above,
2 moles of NaOH reacted with 1 mole of H₂SO₄.
Therefore,
1.805 mole of NaOH will react with = 1.805 / 2 = 0.9025 mole of H₂SO₄.
Finally, we shall determine the volume of H₂SO₄.Mole of H₂SO₄ = 0.9025 mole
Molarity of H₂SO₄ = 0.170 M
Volume of H₂SO₄ =?Volume = mole / Molarity
Volume of H₂SO₄ = 0.9025 / 0.170
Volume of H₂SO₄ = 5.31 LThus, the volume of H₂SO₄ needed for the reaction is 5.31 L
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