Answer/Explanation:
The boy's muscle energy changes into potential energy due to the height. it then converts into kinetic energy as it goes further upwards into the air.
7.71 Classify each of the following as exothermic or endothermic:
a. CHÂ(g) + 2O₂(g) —^> CO₂(g) + 2H₂O(g) + 802 kJ
b. Ca(OH)₂(s) + 65.3 kJ →→→ CaO(s) + H₂O(l)
c. 2Al(s) + Fe₂O3(s) — Al₂O3(s) + 2Fe(s) + 850 kJ
A. Heat is released, so the reaction is exothermic.
B. Heat is absorbed, so the reaction is endothermic.
C. Heat is released, so the reaction is exothermic.
Tobias notices that a particular kind of flower comes in many slightly different shades of pink. In other places, the same flower may be many shades of purple or even blue. He knows that some flowers' colors depend on where they are planted, while others' are determined by their breed. He hypothesizes that the different colors of these flowers are genetically different. Which of the following experimental setups is best for testing this hypothesis?
A hypothesis is a tentative explanation that is put forward for an observation.
What is a hypothesis?A hypothesis is a tentative explanation that is put forward for an observation. In this case, we have to determine whether the location or the kind of breed affects the color of the flowers.
To test the hypothesis, various shades of colors of the flower may be planted on different locations and the growth of each of the shades monitored to ascertain whether the color depends on the location or solely on the kind of breed.
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If 142.5 g of liquid in the coffee-cup calorimeter rises 8.00 °C, how much heat is released by the neutralization reaction?
Q=mcΔt
Q=142.5 x 4.18 x 8
Q = 4.765 x 10³ J
Which is a property of all bases?
Answer:
can change red litmus to blue litmus
Explanation:
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Identify the products formed in this Brønsted-Lowry reaction.
HCO−3+BrO−↽−−⇀acid+base
Answer:
HCO3- + BrO- → HBrO + CO32-
Explanation:
I think this is the answer hope it helps
Question 4 (3 points)
The mass of Jupiter is 1.90 x 1027 kg, and the mass of the Sun is 1.99 x 1030 kg. The average
distance between Jupiter and the Sun is 7.78 x 1011 m. What is the gravitational force they exert
on each other?
Answer:
=4.16×10^23Newton
Explanation:
By using formula,
F= GMm/d^2
What is the ph of a peach with a [ –oh] = 3.2 × 10 –11 m?
vinegar contains 5g of acetic in 100mL of solution so the (w/v)% concentration is:
The (w/v)% concentration of vinegar contains 5g of acetic in 100mL of solution is approx 0.5 %
What is Concentration ?The concentration of a chemical substance expresses the amount of a substance present in a mixture.
There are many different ways to express concentration.(w/v)% is one of them.
Given ;
Mass of solute(acetic acid) is 5.0 g Volume of solution is 100.0 mL.
We need to convert the grams of acetic acid to moles ;
Formula of acetic acid is CH₃COOH
Thus,
Molar mass of acetic acid = 2(12.01) + 4(1.01) + 2(16)
= 24.02 + 4.04 + 32
= 60.06 grams per mol
Moles of acetic acid = 5.0/60.06
= 0.083 moles
(w/v)% = 0.083 x 60 / 1000 x 100
= 0.498 %
= 0.5 %
Hence, The (w/v)% concentration of vinegar contains 5g of acetic in 100mL of solution is approx 0.5 %
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What is gravitational potential energy?
OA. Energy stored in atoms
B. Energy of motion
C. Energy stored in height differences
D. Energy from light
Answer:
c.
Explanation:
gravitational potential energy describes the amount of energy something could have based off of the amount of gravity acting on the object. so energy stored in height difference would be the best answer because gravity is acting on those objec6s
A temperature of 300 Kelvin is how many degrees Celsius?
A. 273
B. 27
C. 573
D. 300
Answer:
The answer is B, to convert kelvin to temperature you :
Subtract 273 (k - 273)
How is the Sun classified?
as a giant star
as a medium star
as a white dwarf
as a neutron star
Answer:
B.) As a medium star
Explanation:
A.) is incorrect. It is not a giant star because there a millions are stars which are much more massive.
B.) is correct. Our Sun has a radius of about 437,000 miles. Technically our Sun is classified as a G-type main-sequence star, aka. yellow dwarf star. The Sun is generally classified as this type of star.
C.) is incorrect. While the Sun's light is similar to the light of white dwarf, it is still most certainly classified as a yellow dwarf star.
D.) is incorrect. Neutrons stars are collapsed, incredibly dense stars. They are around the size of a city.
Answer:
b
Explanation:
took the test
Given the chemical formulas of the following compounds, name each compound and state the rules you used to determine each name. KI, Fe2O3, (NH4)3PO4
Answer:
1.) KI
-------> potassium iodide
Potassium (K⁺) is a metal and iodine (I⁻) is a nonmetal. Therefore, when naming, there are no prefixes denoting how many of each element is in the compound. Because potassium is listed first in the compound, it must be the cation. Because iodine is listed second, it must be the anion. Anions in naming have their endings dropped and have the suffix -ide added.
2.) Fe₂O₃
-------> iron(III) oxide
Iron (Fe³⁺) is a metal and oxygen (O²⁻) is a nonmetal. Therefore, when naming, there are no prefixes denoting how many of each element is in the compound. Because iron is listed first, it is the cation and oxygen is the anion. Both of the elements have charges that do not balance each other (denoted by the subscripts). Because iron can have multiple different charges, the charge of iron (+3) should be listed when naming.
3.) (NH₄)₃PO₄
-------> ammonium phosphate
Ammonium (NH₄⁺) and phosphate (PO₄³⁻) are both polyatomic ions. When these ions bond, they also don't have quantity prefixes. Ammonium is the cation and phosphate is the anion. No roman numerals are necessary because the polyatomic ions always have a particular charge.
Explain how to get it Thanks
The Ammonia present in 2.5 mole of Ammonia is 42.5grams.
What is a mole ?A mole is a measuring unit in Chemistry to measure the number of atoms in certain molar mass of a substance.
It is given that 2.5 mole of Ammonia is present
Grams of Ammonia present in 2.5 mole of Ammonia = ?
Molecular weight of Ammonia = 17 grams.
1 mole of Ammonia = 17 grams of Ammonia
2.5 mole of Ammonia = 17 * 2.5
= 42.5 grams
Therefore 42.5 grams of Ammonia is present in 2.5 mole of Ammonia.
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What hazard symbol does alcohol have? Why?
Answer:
Alcohol has considerable toxic effects on the digestive- and cardiovascular systems. Alcoholic beverages are classified as carcinogenic by the International Agency for Research on Cancer and increase the risk of several cancer types.
Explanation:
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Alcohol has a fire hazard symbol because it is extremely flammable and can create fires. Too be specific, ethanol alcohol is the flammable substance.
Avogadro's number is the number of atoms or molecules in one mole of any substance. In other words, a mole is 6.02X1023 of some chemical unit. The size of the chemical unit does not change Avogadro’s number. An analogy can be made using eggs. You can buy small, medium, or large eggs. The size of the eggs doesn’t affect how many eggs are in one dozen. Similarly, the size of the representative particle doesn’t affect how many are in one mole. Describe your own analogy to show the relationship between moles and the size of representative particles.
Which quantity could best be measured with a meter stick?
A.
the amount of matter in a rock
B.
the width of a wooden block
C.
the volume of water in a cup
D.
the diameter of the Earth
Answer:
B
Explanation:
A meter stick measures distances ( like centimeters) so....B
it does NOT measure mass , volume or VERY large distances (Like earth's diameter)
The quantity could best be measured with a meter stick will be "the width of a wooden block".
What is meter stick?The measurement tool is known as a "meter stick" would be used to measure objects in meters and millimeters.
What is wooden block?A single new piece of wood would be used to create a miniature slit drum known as a wood block.
An instrument for measuring lengths in meters and centimeters is a meter stick, which measures one meter (hundred centimeters). A meter stick can be used to measure things such as the width of a bag or the length of a table.
The quantity that could best be measured with a meter stick will be "the width of a wooden block".
Therefore, the correct answer will be an option (b)
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Calculate the moles for C. and D. in the attached picture:
The moles of nitrogen (iv) oxide produced in C and D are 0.284 moles and 68.32 moles respectively.
What is the mole ratio of the reaction?The mole ratio of the given reaction shows that 2 moles of dinitrogen (v) oxide produces 4 moles of nitrogen (iv) oxide when it decomposes.
B of dinitrogen (v) oxide in 15.4 g is calculated below:
Molar mass of dinitrogen (v) oxide = 108 g/mol
Moles of dinitrogen (v) oxide = 15.4/108 = 0.14 moles
Moles of nitrogen (iv) oxide produced = 0.142 * 2 = 0.284 moles
Moles of dinitrogen (v) oxide in 3.69 kg is calculated below:
Molar mass of dinitrogen (v) oxide = 108 g/mol
Mass = 3.69 kg = 3690 g
Moles of dinitrogen (v) oxide = 3690/108 = 34.16 moles
Moles of nitrogen (iv) oxide produced = 34.16 * 2 = 68.32 moles
Therefore, the moles of nitrogen (iv) oxide produced in C and D are 0.284 moles and 68.32 moles respectively.
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Fill in the blank with the correct number to balance the equation: 4AI +____O2 → 2Al₂O3.
(Enter only a whole number.)
Answer: 3 O2
Explanation:
4AI +____O2 → 2Al₂O3.
In the product, Al and O3 are one chemical now and therefore BOTH impacted by the coeffcient in front of the Al which is 2. We know the coefficient is 2 and there are 3 molecules of O meaning that there are 6 molecules of O in the product. To balance this, there should be 6 molecules of O on the reactant side, the same way there is 4 Al molecules on both sides of the reaction. So 6 divided by 2 is 3 so put a 3 in the blank.
Describe the characteristics that identify a sample of matter as being a substance.
No matter how big or little a material is, its properties remain the same. Size, form, color, and mass are the qualities that distinguish a material from non-substances. All of these qualities, including size, shape, color, and mass, can be seen and measured. Some characteristics are physical, while others are chemical. Physical characteristics include mass, volume, density, and color. Viscosity and solubility are examples of chemical qualities.
Determine the trends in radii for the following ions and atoms: Mg2+, F- , Ne, and Na+ .explain your choice
The trend for the radii is Mg²⁺ < Na+ < Ne <F⁻
What does Ionic size varies with number of protons ?With the increase in number of protons in the nucleus the electrons are more attracted towards nucleus and so the ionic radius decreases.
Ionic size increases with the addition of electrons and ionic size decreases with the loss of electrons.
Higher is the atomic number, higher will be the effective nuclear charge, lower will be the size.
F⁻
no. of proton=9
no of electron = 10
Na+
no. of proton=11
no of electron=10
Mg²⁺
no. of proton=12
no of electron=10
Ne
no. of proton=10
no of electron=10
Mg²⁺ < Na+ < Ne <F⁻
Therefore the trend for the radii is Mg²⁺ < Na+ < Ne <F⁻
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describe what happens when two substances at different tempatures come into contact. describe how the law of conservation of energy applies to this system
If two objects at different temperatures are brought in contact with each other, energy is transferred from the hotter object to the colder object.
What is the law of conservation of energy?The total energy of an isolated system remains constant irrespective of whatever internal changes may take place with energy conevrting in one form and reappearing in another.
When two substances at different temperatures come into contact, the substance with a higher temperature will transfer heat energy to the substance with a lower temperature, until their temperatures get equal.
Here, if the two substances are isolated then the law of conservation of energy states that the when heat released by the substance with a higher temperature is the same amount of heat gained by the substance lower a lower temperature.
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Which buffer can be suitable to prepare a solution that needs to be buffered at ph 4?
Answer:
For pH= 4.00 :
Add 0.1 ml of 0.1 molar NaOH to 50 ml of 0.1 molar potassium hydrogen phthalate .
How much 5.50M NaOH must be added to 680.0 mL of a buffer that is 0.0215 M acetic acid and 0.0270 M sodium acetate to raise the pH to 5.75?
5.50M NaOH must be added to 680.0 mL of a buffer, The amount of NaOH is mathematically given as
V=2.107mL
What is the volume of 5.50M NaOH?Generally, the equation for Chemical Reaction is mathematically given as
CH3COOH+OH^{-} ⇄ CHCOO^{-} + H2O
Therefore
pka=-log(1.8*10{-5})
pKa=5-0.25527
pKa=4.3447
Hence
[tex]pH=pKa+log\frac{CH3COO}{CH3COOH}\\\\0.75=4.7447+log\frac{0.01564+x}{0.01428-x}[/tex]
x=0.0115898
Volume of NaOH
V=0.0021072L
V=2.107mL
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How many taste buds are present on the tongue? Name them.
there are five Taste bud present tongue they are -
SWEET SALT SOUR BITTER UMAMI ______________________out of the four type of papillie present on tongue the fungiform circumvallate and folite papillie contain numerous small taste but few such type of Taste but also occur in the mucous membranes of soft palate tonsils and epiglottis all of these days but received taste is normally
each Taste bud is an oval structures formed due to modification of epithelial cells which are situated erect and vertically on the surface long sensory cells and supporting cells are found in this bird is sensory cell is spindle shaped in which a sensory here is found at its free in the century fibre of the facial and vagus cranial nerves are wrapped around the basal and of the gustatory cells each test but open on the epithelial surface through minute taste pore
____________________Guillaume Amontons first took a stab at measuring absolute zero in 1702. What would be the most reasonable way it would have been done then
The most reasonable way to measure absolute zero would have been to extrapolate the ideal gas law.
What is Absolute zero?This is referred to the temperature at which a thermodynamic system has the lowest form of energy.
Guillaume Amontons used gas equation to prove that absence of heat was theoretically possible which would have involved only extrapolating the ideal gas law.
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Is any of the following an acid?
a. Ba(OH)2
b. H3PO4
c. FeCl3
d. NaC2H3O2
e. No acids are listed.
Answer:
b
Explanation:
A phase diagram for elemental carbon is shown below.
Starting at liquid carbon, which action(s) would produce carbon gas?
Answer:
C.) lowering the pressure
Explanation:
As you can see, the liquid and gas phases are stacked right on top of each other. Since temperature is on the x-axis, this means that these phases exist at the same temperature (disregarding any other variables). This means that changing the temperature would not change the liquid phase to the gas phase.
If we want to get the sample into the gas phase, we need to manipulate the sample based on the y-axis. To lower the sample into the gas phase, we need to lower the pressure, which is the variable on the y-axis. This will work because pressure decreases as you go down the y-axis.
ements
tton
2 NH3 + 3 CuO -->3 Cu + N₂ + 3H₂O
In the above equation how many moles of N₂ can be made when 156.1 grams of CuO are
consumed?
Round your answer to the nearest tenth. If you answer is a whole number like 4, report
the answer as 4.0
Use the following molar masses. If you do not use these masses, the computer will mark
your answer incorrect.:
Element Molar Mass
Hydrogen 1
Nitrogen 14
Copper 63.5
Oxygen 16
Answer: The amount of moles that can be produced when 156.1 grams of CuO are consumed is .653 moles.
Explanation: The first thing to do is to convert the 156.1 grams of Copper(II) Oxide (CuO).
In order to convert the 156.1 grams of Copper(II) Oxide to moles we have to first calculate the molar mass of Copper(II) Oxide. This can be done by simply adding the Copper's molar mass, 63.5, to the Oxygen's molar mass, 16.
16 g + 63.5 g = 79.5 g
Once you have obtained the molar mass of the Copper (II) Oxide you can then proceed to convert the 156.1 grams from before into moles.
This is done by multiplying 156.1 grams by 1 mole / 79.5 grams.
[tex]156.1 g *1 moles/79.5 g = 1.96 moles[/tex]
Now that you have calculated the 1.96 moles of Copper(II) Oxide, you need to set up an equation to convert between moles amounts.
This can be done by looking at the coefficients in the chemical equation. So, in this chemical reaction, it tells us for every 3 moles of CuO there is 1 moles of N2.
With this we can write a conversion equation as follows.
[tex]1.96*\frac{1}{3} = .653[/tex]
*Note: in conversion equations the denominator should match the units and or element being multiplied by the other fraction in the numerator. Such as in this instance the 1.96 moles of CuO and 3 moles of CuO are the same.
So, the amount of moles of N2 that can be made when 156.1 grams of CuO are consumed is .653 moles.
Answer:
0.7 mole N₂
Explanation:
To find the amount of N₂ produced, you need to (1) convert grams CuO to moles CuO (via the molar mass) and then (2) convert moles CuO to moles N₂ (via mole-to-mole ratio from reaction coefficients).
The molar mass is the sum of the element molar masses times their quantities. The ratios/conversions should be arranged in a way that allows for the cancellation of units (desired unit in the numerator).
Molar Mass (CuO): 63.5 g/mol + 16 g/mol
Molar Mass (CuO): 79.5 g/mol
2 NH₃ + 3 CuO ----> 3 Cu + 1 N₂ + 3 H₂O
^ ^
156.1 g CuO 1 mole 1 mole N₂
------------------- x ----------------- x ---------------------- = 0.7 mole N₂
79.5 g 3 moles CuO
What does the prefix cis-in the name of a stereoisomer indicate about the
functional groups?
Which of the following is the best definition of a physical change?
A. A change in a substance where a new substance is formed
B. A change in a substance in which mass is conserved
C. A change in a substance inwhich bonds are broken
D. A change in a substance with no new substances being formed
D. A change in a substance with no new substances being formed
Explanation:There are 2 ways a substance can change, physical changes and chemical changes. In all changes, physical or chemical, mass is always conserved.
Physical vs. Chemical
The main difference between a physical and chemical change is the substance at the end.
Physical changes do not form new substancesChemical changes do form new substancesNew substances are only created by chemical changes. Additionally, only chemical changes break apart bonds. Physical changes maintain the same compounds and elements, so bonds are not broken.
Examples of Physical Changes
Physical changes do not change the actual substance, but they can change the form of the substance.
MeltingBoilingFreezingCrumblingCuttingBreakingAll of these change the state of matter or shape of the substance, but not the chemical makeup.
