What example involves a phase change in which heat energy is released by the substance
Spontaneous phase changes that leads to an increase in the stability of a substance would release energy. For example, converting a gas to its liquid state such as cooling water vapor below its boiling point releases energy. Cooling allows water molecules to establish intermolecular hydrogen bonds to produce a liquid while releasing energy. The formation of bonds between water molecules is so exothermic that a steam scald can be significantly more serious to treat than a hot water scald.
Answer:
Freezing ice cream :)
Explanation:
i got it right on edge 2021
You are on an alien planet where the names for substances and the units of measures are very unfamiliar.
Nonetheless, you obtain 8 quibs of a substance called skvarnick in units of sleps; not quibs.
9 sleps is equal to 13 quibs.
If you have 8 quibs of skvarnick, how many sleps do you have?
Round your answer to the nearest tenth (one decimal place). Type only the number; not the number and unit
Given that in the alien planet the names of substances and the units in which they are measured in not familiar.
8 quibs of a substance called skvarnik is present.
The conversion factor between sleps and quibs is: 9 sleps = 13 quibs
Converting 8 quibs of skvarnick to sleps:
[tex]8 quibs * \frac{9 sleps}{13 quips}= 5.54sleps[/tex]
5.54 when rounded to nearest tenth becomes 5.5.
So the correct answer would be 5.5
Validate how valence electrons determine the chemical reactivity of an element: give 2 examples of elements with high reactivity and justify your response.
A basketball weigh more after it was inflated with air then when it was deflated how does this show that gas is matter
The fact that a basketball weighs more when inflated compared to when it's deflated is indicative that gas (air, in this case) is matter because it contributes to the mass and occupies space within the basketball.
Explanation:The phenomenon that a basketball weighs more after it is inflated with gas (in this case, air) compared to when it is deflated, shows us that gases have mass and occupy space, hence they are considered matter. The principle of matter states that it has mass and occupies space. When you inflate the basketball, you are filling it with air, which is a gas, and increases the total mass of the basketball. Thus, making the basketball heavier than it was when it was deflated. This change in weight clearly demonstrates that gas is indeed matter as it contributes to the overall mass of the basketball.
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A sample of a substance has a mass of 27.3 grams and a volume of 7.0 centimeters3. The density of this substance is _____ grams/centimeter3.
density = mass/volume=27.3/7=3.9
The density is defined as mass of a substance per unit of its volume
It can be expressed in different units like g/L g/m3 Kg/dm3 etc
We are given that
mass of substance = 27.3 grams
volume of substance = 7 cm^3
the density = Mass of substance / volume of substance
density = 27.3g / 7 cm^3 = 3.9 g /cm^3
J.J. Thomson's experiments supported the existence of a particle that deflected away from a negative charge and toward a positive charge. Ernest Rutherford found that when positive particles were fired at gold foil, some of the particles deflected rather than passing straight through. Taken together, these experiments support our understanding of the
A. Flavors or quarks
B. Structures of the atom
C. Specific gravity of gold
D. Law of Conservation of energy
a balanced ball on a basketball hoop is potential energy or kinectic energy?
potential energy
Explanation:An object has potential energy if it is above the ground. For example, if the basketball is sitting still on a table, it has potential energy but no kinetic energy. Potential energy is the stored energy of position possessed by an object. Potential energy is associated with forces that act on a body in a way that the total work done by these forces on the body depends only on the initial and final positions of the body in space. So the balanced ball on basket ball hoop has stored energy in it i.e. potential energy.
An atom has 9 electrons and 9 protons at the start . If it loses 2 electrons, the net charge on the atom will be ? If the atom instead gains 4 electrons the net charge will be ?
Answer : If it loses 2 electrons, the net charge on the atom will be (+2) and If it gains 4 electrons, the net charge on the atom will be (-4).
Explanation :
We are given:
Number of electron in an atom = 9
Number of protons in an atom = 9
Atomic number is defined as the number of protons or electrons that are present in a neutral atom.
Atomic number = number of protons = number of electrons
An ion is formed when an atom looses or gains electron.
When an atom looses electrons, it will form a positive ion known as cation.
When an atom gains electrons, it will form a negative ion known as anion.
According to the question,
When the atom loses 2 electrons then the net charge on the atom will be (+2) because it will form a positive ion by losing electrons.
When the atom gains 4 electrons then the net charge on the atom will be (-4) because it will form a negative ion by gains electrons.
how would convert 1450000mg to scientific notation and what's the answer PLEASE ANSWER!!!
1450000mg is 1.45mg x 10^6
The decimal point in 1450000 would be after the last zero so you move that decimal point until it reaches before the last number which is 1 so that gives you 1.45. Count how many times you moved from the original decimal position to the decimal point after 1. The number of times you moved will be your exponent. If you want to check if your answer is right, then move the decimal point of 1.45 to the right by the number of your exponent.
What is the pH of a solution with a concentration of 3.6 × 10-5 molar H3O+? Show, or explain, the work used to solve this problem.
Answer:
pH = 4.44
Explanation:
You take the negative logarithm of the hydronium ion concentration.
pH = -log[H₃O⁺] = -log(3.6 × 10⁻⁵) = 4.44
Answer:
pH = 4.45
Explanation:
pH is negative logarithm of the hydrogen ion concentration.
Given, hydronium ion concentration = 3.6 x 10⁻⁵
pH = - log[H₃O⁺] = - log(3.6 x 10⁻⁵) = 4.45
A pH below 7.0 means the solution is acidic. Neutral pH is at 7.0. For pH above 7.0 the solution is basic.
Joey and Ross designed an experiment to test the effectiveness of the newest acne cream on the market, Zit-B-Gone. Joey followed the manufacturer's directions for a total of 10 days. Each day Joey and Ross counted the number of blemishes on Joey's face and recorded the results. At the end of the 10 days, they created a line graph of their data. They concluded that Zit-B-Gone was not effective in removing blemishes. Janice, a representative from the company, sees their results and tells them, "Zit-B-Gone works just fine...Look at how your blemishes decreased in the first few days." How should Joey and Ross respond to Janice?
A) They should ignore the data after day 5 and agree with Janice.
B) They should restart the whole experiment and throw out all of the current data.
C) They should say that Zit B Gone was not effective because the blemishes reappeared.
D) They should agree with Janice and realize that they have looked at the data wrongly.
The correct answer is C
Joe and Ross should respond to Janice by saying that Zit B Gone was not effective because the blemishes reappeared.As the blemishes reappeared there could possibly be an error in their results.
What is an error?Errors in chemical analysis result when there is a difference between observed value and the true value.If the magnitude of errors is large , it results in decrease in accuracy, reproducibility, and precision.
There are three types of errors:1) random error 2) systematic error 3) human error.The cause of random errors are difficult to quantify while the human errors can be minimized by taking a range of readings to reduce the error.
Errors while measuring boiling point may be human errors while noting down the boiling temperature or instrumental or systematic error if there is a fault in the thermometer.
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What evidence supports Bohr’s claim that an electron is found only in specific energy levels around the nucleus of the atom. And then connect this evidence to the claim through reasoning
Energy Levels of Electrons. As you may remember from chemistry, an atom consists of electrons orbiting around a nucleus. ... They are restricted to orbits with only certain energies. Electrons can jump from one energy level to another, but they can never have orbits with energies other than the allowed energy levels.
The evidence that support Bohr's claim is that electron can only emit light when its energy level changes.
Bohr proposed an atomic model in which;
the electrons found in an atom can only occupy orbits for which the angular momentum is quantized, which results in discrete values of energy level. the electrons in such stationary state or ground state emits no light, if an electron jumps to a lower state, it emits a photon whose energy equals the difference in energy between the two states.
Thus, we can conclude that the evidence that support Bohr's claim is that electron can only emit light when its energy level changes.
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Based on their locations in the periodic table, which best compares the properties of the metalloids arsenic and antimony?
Answer:
Arsenic has a more nonmetallic behavior than antimony because arsenic's atoms have fewer electron shells.
Explanation:
What is the pH of a solution with a hydronium (H3O+) concentration of 5.6 × 10-9 M? Use the table to help you.
Answer:
pH = 8.25
Explanation:
pH = -log[H₃O⁺] = -log(5.6 × 10⁻⁹) = 8.25
Answer:
pH of the solution is 8.25 (≅8.3)
Explanation:
Given:
H3O+ ion concentration = 5.6*10⁻⁹ M
To determine:
pH of the given solution
Explanation:
pH is related to the hydronium ion concentration as follows:
[tex]pH = -log[H3O+]\\[/tex]
For the given solution
[tex]pH = -log[5.6*10^{-9}] = 8.25[/tex]
What is the chemical name of the compound K2SO4?
Potassium Sulfate
Explanation:Potassium sulfate is a non-flammable white crystalline salt which is soluble in water. The chemical compound is commonly used in fertilizers, providing both potassium and sulfur.
how would isopropanol behave when poured out of its container onto a table
Isopropanol spread on a table will form a layer that evaporates quickly and may cool the surface or damage materials sensitive to alcohol. It is also flammable, creating a fire risk near open flames or heat sources.
When isopropanol is poured out of its container onto a table, it behaves similarly to how water or other liquids would behave. Due to its low viscosity, isopropanol will spread out across the table's surface, forming a thin layer.
Since isopropanol evaporates much faster than water at room temperature, it would begin to evaporate quickly, leaving behind a cool sensation due to the evaporation process removing heat from the surroundings. If the table is made of a material that can be degraded by alcohol, such as certain plastics or finishes, the isopropanol may also cause damage to the table's surface.
Furthermore, it's important to note that isopropanol is flammable, so if it is poured near an open flame or a heat source, there is a risk of ignition. Therefore, handling isopropanol should be done with caution, and proper ventilation should be ensured to prevent the build-up of flammable vapors.
What is an ephemeral stream? A)one that flows only after rainfall B) one that flows only in flat lands C) one that is formed only from mechanical weathering D) one that is formed only from chemical weathering
Answer: Option (a) is the correct answer.
Explanation:
The stream that flows during or after the rainfall is called an ephemeral stream. This stream occurs in areas where there is less rainfall or deficiency of moisture.
The stream that flows only in flat lands is called as river.
Mechanical weathering results in the breaking of rocks causes ice wedging.
Chemical weathering results in the change in molecular structure of rocks and soil.
Thus, it can be concluded that option (a) is the correct answer.
If u like a gurl how woud u kno (plz i need to kno)
Answer:
do u got a MAN
Explanation:
CUZ i GOTTA KNOW
What word or two-word phrase best describes the shape of the fluoroform molecule?
The two-word phrase that best describes the shape of the fluoroform molecule is ; Tetrahedral
Fluoroform is a chemical compound represented by the formula CHF₃ which falls within the class of haloforms. The center atom in a fluoroform molecule is the carbon atom which has ( 3 ) C - F bonding and ( 1 ) C - H bonding. This means that the number of electrons is in a fluorocarbon is 4, hence according to VSEPR theory the geometry of the fluoroform molecule will be Tetrahedral.
Hence we can conclude that The two-word phrase that best describes the shape of the fluoroform molecule is ; Tetrahedral
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The shape of the fluoroform molecule is trigonal pyramidal.
Explanation:The shape of the fluoroform molecule is trigonal pyramidal.
A trigonal pyramidal shape occurs when a central atom is bonded to three other atoms and has one lone pair of electrons. In the case of fluoroform (CHCl3), the central carbon atom is bonded to three fluorine atoms and has one lone pair of electrons, resulting in a trigonal pyramidal shape.
Other examples of molecules with trigonal pyramidal shape include ammonia (NH3) and phosphine (PH3).
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Which statement best describes the trend in atomic radii observed in the periodic table?
1. The atomic radii increase, moving across a period to the right and up in a group.
2. The atomic radii increase, moving across a period to the left and down in a group.
3. The atomic radii increase, moving across a period to the left and up in a group.
4. The atomic radii increase, moving across a period to the right and down in a group.
Answer: The correct answer is Option 2.
Explanation:
Atomic radius of an atom is defined as the total distance from the nucleus to the outermost shell of the atom.
As moving from top to bottom, there is an addition of shell around the nucleus and the outermost shell gets far away from the nucleus and hence, the distance between the nucleus and outermost shell increases. Thus, increasing the atomic radii of the atom.
As moving from left to right in a period, more and more electrons get added up in the same shell and the attraction between the last electron and nucleus increases, which results in the shrinkage of size of an atom. Thus, decreasing the atomic radii of the atom on moving towards right of the periodic table.
Hence, the correct answer is Option 2.
Atomic radii decrease from left to right across a period due to increased nuclear charge and increase down a group as additional electron shells are added. This makes atomic size trend to the lower left corner of the periodic table. As a result, choice 2 is accurate..
The periodic table shows a distinct trend in atomic radii. The atomic radii shrink from left to right during a time. This is because as more protons are added to the nucleus, the increased positive charge pulls the valence electrons closer, reducing atomic size.
Conversely, as you move down a group in the periodic table, the atomic radii increase. This occurs because new electron shells are added, placing the valence electrons farther from the nucleus, hence increasing the atomic size.
Therefore, the best description of the trend in atomic radii is:
The atomic radii rise, traveling in a group to the left and down over a period of time..Which term identifies the dark smooth areas on surface of the moon
The dark smooth areas on the surface of the moon is called Maria.
Maria is made up of solidified lava which is a result of volcanic activity on the moon.
When Galileo observed these smooth dark spots on the moon he called them 'mare' which is latin for 'sea'. And the plural form of mare is 'maria'. Unlike Galileo predictions, recent investigations confirm that maria are not oceans but solidified lava.
Justin Bleeber is a lazy young man and decides to burn a pile of leaves instead of bagging it. The pile of leaves weighed three pounds before being burned. After the leaves are burned the leftover ash weighs half a pound. What happened to the rest of the mass of the leaves? A) It was destroyed. B) It soaked into the ground. C) It compacted into the ash. D) It was turned into smoke and gas.
Answer is: D) It was turned into smoke and gas.
Conservation of mass (mass is never lost or gained in chemical reactions), during chemical reaction no particles are created or destroyed, the atoms are rearranged from the reactants to the products.
Gas that escaped is probably carbon(IV) oxide and little carbon(II) oxide, so the mass of product measured is less than reactants.
If mass of gas is also measured, masses of reactants and products are the same.
The movement of organisms into a range is called
A. immigration.
B. emigration.
C. population shift.
D. carrying capacity.
Immigration is the movement of organisms into a population, increasing its size and growth rate. Emigration is the movement out of a population. Carrying capacity is the maximum population size that the environment can sustain. Hence, option A, immigration, is correct.
The movement of organisms into a range is called immigration. Immigration is the movement of individuals into a population from other areas, which increases the population size and growth rate. In contrast, emigration refers to the movement of individuals out of a population's range. When an animal migrates, it does so because it can find resources there or because the habitat is a good fit for it. When an animal emigrates, it signifies that its natural habitat is no longer good for it and that it must find a new one. The definition of population change is a shift in the proportions of the various groups of people that make up a population. Carrying capacity is related to population size as well, but it describes the maximum number of individuals of a species that the environment can support, not the movement into a range. Thus, the correct answer to the question is A. immigration.
Which of the following laws can be described as, “within every force interaction, each object exerts the same amount of force on the other object, but in the opposite direction.”
Newton’s second law
Newton’s fourth law
Newton’s third law
Newton’s first law
The correct answer is Newton’s third law.
According to Newton’s third law of motion to every action there is an equal and opposite reaction.
Action and reaction forces form the crux of Newton's third law of motion.
Push and pull are two examples of action and reaction forces. Also the action and reaction forces act on two different objects.
Answer:
"Newton's third law of motion"
Explanation:
Sir Issac Newton has given three laws of motion namely,
Newton’s first law Newton’s second law Newton’s third lawNewton's first law of motion gives the introduction of force. Newton's second law of motion gives the magnitude of force and Newton's third law of motion can be described as "within every force interaction, each object exerts the same amount of force on the other object, but in the opposite direction".
So, the correct option is (c) "Newton's third law of motion".
How does the activity series help determine the anode of a voltaic cell?
The anode is the metal that is higher on the list because it is more easily reduced.
The anode is the metal that is lower on the list because it is more easily reduced.
The anode is the metal that is higher on the list because it is more easily oxidized.
The anode is the metal that is lower on the list because it is more easily oxidized.
The anode is the metal that is higher on the list because it is more easily oxidized.
Answer: The anode is the metal that is higher on the list because it is more easily oxidized.
Explanation: The Anode of the voltaic cell is the electrode on which the process of oxidation takes place.
Oxidation is the process in which highly reactive metal which is higher in the electrochemical series loses electrons which goes into the solution.
Thus The anode is the metal that is higher on the list because it is more easily oxidized.
For eg- In a reaction cell of Copper-Iron, Iron(Fe) will get oxidized because it is placed higher in the electrochemical series whereas Copper(Cu) will get reduced.
Combustion of 28.30 g of a compound containing only carbon, hydrogen, and oxygen produces 32.75 gco2 and 13.41 gh2o. What is the empirical formula of the compound?
The empirical formula is C₂H₄O₃.
We must calculate the masses of C, H, and O from the masses given.
Mass of C = 32.75 g CO₂ × (12.01 g C/44.01 g CO₂) = 8.9372 g C
Mass of H = 13.4 g H₂O × (2.016 H/18.02 g H₂O) = 1.5067 g H
Mass of O = Mass of compound - Mass of C - Mass of H
= (28.30 – 8.9372 – 1.5067) g = 17.856 g
Now, we must convert these masses to moles and find their ratios. If the ratios are not integers, we multiply them by a number to make them close to integers.
From here on, I like to summarize the calculations in a table.
Element m/g n/mol Ratio ×2 Integers
C 8.9372 0.74415 1 2 2
H 1.5067 1.4948 2.0086 4.0174 4
O 17.856 1.1160 1.4997 2.9994 3
The empirical formula is C₂H₄O₃.
Final answer:
To determine the empirical formula of the compound, the masses of products from combustion are used to calculate the moles of carbon, hydrogen, and oxygen. These are then converted to a mole ratio and simplified to a whole number ratio. The empirical formula of the compound is C2H4O3.
Explanation:
To find the empirical formula of a compound from the given combustion data, we start by converting the masses of CO2 and H2O produced to masses of carbon and hydrogen. From the mass of carbon dioxide, we determine the mass of carbon in the compound. Since 1 mole of CO2 contains 1 mole of carbon atoms, and the molar mass of carbon is 12.01 g/mol, we can calculate the amount of carbon.
32.75 g CO2 × (1 mol CO2 / 44.01 g CO2) × (12.01 g C / 1 mol C) = 8.93 g of Carbon
Next, from the mass of water, we determine the mass of hydrogen in the compound. As 1 mole of H2O has 2 moles of hydrogen atoms, we calculate the hydrogen mass as follows:
13.41 g H2O × (1 mol H2O / 18.02 g H2O) × (2 g H / 1 mol H) = 1.49 g of Hydrogen
The remaining mass must be oxygen, as it's the only other element present. Subtracting the masses of carbon and hydrogen from the total mass of the compound gives us the mass of oxygen in the compound:
28.30 g compound - 8.93 g C - 1.49 g H = 17.88 g of Oxygen
Converting the masses of carbon, hydrogen, and oxygen to moles, we get:
C: 8.93 g / 12.01 g/mol = 0.744 molH: 1.49 g / 1.008 g/mol = 1.477 molO: 17.88 g / 16.00 g/mol = 1.117 molTo find the simplest whole number ratio, we divide the moles of each element by the smallest number of moles calculated, which is for carbon (0.744 mol):
C: 0.744 mol / 0.744 mol = 1H: 1.477 mol / 0.744 mol ≈ 2O: 1.117 mol / 0.744 mol ≈ 1.5Since we can't have a half in an empirical formula, we multiply each ratio by 2 to get whole numbers:
C: 1 × 2 = 2H: 2 × 2 = 4O: 1.5 × 2 = 3Thus, the empirical formula of the compound is C2H4O3.
Which statement explains how this type of fossil differs from a trace fossil?
This fossil reveals the activities of an organism.
This fossil was created in solidifying sediment.
This fossil is an impression left by an organism.
This fossil was an organism that has been turned into rock.
In an ecosystem, this type of fossil differs from a trace fossil as this fossil was an organism that has been turned into rock.
What is an ecosystem?
Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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Answer: D
Explanation:
Which of the ailments listed had a frequency of three?
i need to see the frequencies.
Which of these is a balanced chemical equation?
Answer: option H
Explanation:
Balanced equation means that the no of atoms on both sides should be equal.
In H, Cl2 + 2NaBr-------> Br2 + 2NaCl
No of Cl atoms, 2=2
No of Br atoms, 2=2
And sodium atoms,2=2
Hence it is balanced equation
And remain are not balanced.
Which sample of matter is a mixture? Air, water, ammonia
I think air is a mixture. Water and ammonia are compounds.
Air is a mixture. Water and ammonia are compounds.
What is a mixture?A mixture is composed of one or more pure substances in varying compositions.
There are two types of mixtures: heterogeneous and homogeneous.
Air is a mixture of various gases like nitrogen, oxygen, methane, nitrous oxide, etc. These gases retain their properties in air and hence the air is considered a mixture.
Ammonia is a simple compound composed of one atom of nitrogen and three atoms of hydrogen.
Water is also a simple compound composed of one atom of oxygen and two atoms of hydrogen.
Hence, Air is a mixture. Water and ammonia are compounds.
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