Burning wood is a chemical change.
Among the given options, burning wood is an example of a chemical change as it leads to the formation of new substances, namely, carbon dioxide, water vapor, and ash.
Explanation:The correct option for an example of a chemical change among the given choices is burning wood. Chemical change involves forming new substances with new properties. In the process of burning wood, wood (cellulose) reacts with oxygen in the air to form carbon dioxide, water vapor, and ash, which are completely different substances from the original wood and oxygen. The other three options, filtering a mixture, boiling water, and crushing a can, are physical changes because they do not result in any new substances being formed; they only change the state, shape, or appearance of the substance.
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Which equation obeys the law of conservation of mass?
A.
2Fe + 3O2 → 2Fe2O3
B.
4Fe + O2 → 2Fe2O3
C.
Fe + O2 → Fe2O2
D.
4Fe + 3O2 → 2Fe2O3
PLLLLLSSS HELP!!!!!!!!!!!!!!!!!! What are the roles of the substances in the equation?
A- The substances 3CO2 and 4H2O are reactants that react to form the products C3H8 and 5O2.
B-The substances C3H8 and 3CO2 are reactants that react to form the products 5O2 and 4H2O.
C-The substances C3H8 and 5O2 are reactants that react to form the products 3CO2 and 4H2O.
D- The substances 5O2 and 3CO2 are reactants that react to form the products C3H8 and 4H2O.
The substances C3H8 and 5O2 are the reactants and 3CO2 and 4H2O are the products in the equation. These reactants combine to form the products in a process known as a chemical reaction, more specific, a combustion reaction.
Explanation:The correct answer is C: The substances C3H8 and 5O2 are reactants that react to form the products 3CO2 and 4H2O. In a chemical reaction, the reactants are the substances that start the process, and they are normally written on the left side of a chemical equation. The products are the substances that are produced, and they are usually written on the right side of the chemical equation.
For instance, in the chemical equation you've mentioned (C3H8 + 5O2 -> 3CO2 + 4H2O), the reactants - propane (C3H8) and oxygen (5O2) combine to form carbon dioxide (3CO2) and water (4H2O). Hence, the reactant side has C3H8 and 5O2, while the product side has 3CO2 and 4H2O. This reaction is an example of a combustion reaction.
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Which statements describe organic compounds? Check all that apply.
Organic compounds are commonly found in living things.
Organic compounds are not associated with or made from living things.
Organic compounds contain carbon.
Organic compounds usually lack carbon. Organic compounds are found in food.
Answer: The answers are A C E. I took the test.
Explanation:
Select the correct answer.
Lyndon is investigating whether putting plastic on her windows will help seal out cold winter drafts. She covers a window on the south side of her house with plastic and measures the inside temperature near the window. She also measures the inside temperature near a window without plastic on the north side of her house. The windows are the same size and design. Why is this not an ideal controlled investigation?
A. The windows should be different sizes to introduce variation.
B. The drafts at each window may be different because the windows aren’t near each other.
C. Temperature isn’t a good indicator of cold winter drafts.
D. Outside temperature is a better indicator of cold winter drafts than inside temperature.
E. The type of plastic used in the investigation isn’t mentioned.
Answer: B
Explanation: PLATO
You have a cup of water and a packet of powdered juice mix. You stir some of the powder into the cup of water and it quickly dissolves. You decide to add more juice mix to the cup and stir again. Again, the powder quickly dissolves. What can you conclude about the juice powder and water solution?
The powdered juice mix quickly dissolves in the water, indicating that it forms a solution. Stirring the mixture can increase the rate of dissolution. The fact that the mix dissolves again when more is added suggests that the solution was not saturated.
Explanation:The fact that the powdered juice mix quickly dissolves when added to the cup of water suggests that it forms a solution with the water. A solution is a homogenous mixture in which the solute particles are very small and become uniformly dispersed throughout the solvent. The rate of dissolution can be increased by stirring the mixture, which allows fresh solvent molecules to continually come into contact with the solute. Additionally, the fact that the mix quickly dissolves again when more is added suggests that the solution was not saturated and still had room for more solute to be dissolved.
Final answer:
The powdered juice mix forms a stable solution with the water, as indicated by its quick and complete dissolution. The act of stirring increases the rate of dissolution by allowing fresh solvent molecules to interact with the solute particles. The solution remains stable, without any settling or changes, and can pass through a filter without any separation.
Explanation:
The quick dissolution of the powdered juice mix in the cup of water indicates that it forms a stable solution. When a solute, such as the juice mix, is fully dissolved in a solvent, like water, it creates a homogeneous mixture called a solution. In this case, the solute particles in the juice mix are very small, allowing them to dissolve easily in the water.
Stirring the solution aids in dissolving more of the juice mix because it increases the frequency of collisions between the solvent molecules (water) and the solute particles (juice mix), increasing the rate of dissolution. Agitating the solution ensures that fresh solvent molecules continuously come into contact with the solute, speeding up the process.
By observing the quick dissolution of the juice mix and its ability to stay in solution without settling or changing upon passing through a filter, we can conclude that the juice powder and water solution forms a stable and fully dissolved mixture.
Which of the following is not an intensive physical property?
A. Electrical conductivity
B. Mass
C. Density
D. Freezing point
The answer should be "A. Electrical Conductivity". I really hope I helped! Have a great day!
what is the molar mass of BaBr2?
multiple choice on the picture
B. 297.1 g/mol
Is your answer! ;)
Answer: Option (B) is the correct answer.
Explanation:
Molar mass is defined as the sum of atomic mass of all the atoms present in a compound.
For example, atomic mass of barium (Ba) is 137.32 g/mol and atomic mass of a bromine atom is 79.90 g/mol.
Therefore, calculate molar mass of [tex]BaBr_{2}[/tex] as follows.
Molar mass = atomic mass of Ba + 2 [tex]\times atomic mass of Br[/tex]
= [tex]137.32 g/mol + 2 \times 79.90 g/mol[/tex]
= 297.12 g/mol
Therefore, we can conclude that molar mass of [tex]BaBr_{2}[/tex] is 297.1 g/mol.
How many alcohols and ethers share the molecular formula c2h6o?
Answer is: there are two compounds with molecular formula C₂H₆O, one alcohol and one ethar.
Alcohol with molecular formula C₂H₆O is ethanol or ethyl alcohol (C₂H₅OH).
Ethanol is a volatile, flammable, colorless liquid with characteristic odor.
Ether with molecular formula C₂H₆O is dimethyl ether (CH₃OCH₃).
Dimethyl ether is a colorless gas.
Answer:
Alcohol :CH₃-CH₂-OH (ethanol)
Ether: H₃C-O-CH₃ (dimethyl ether)
Explanation:
Alcohols are compounds containing the hydroxyl or the -OH functional group i.e. R-OH where R is an alkyl or aryl group
Ethers are compounds with a general structure, R-O-R' where R and R' are once again either alkyl or aryl groups.
The given compound has a molecular formula: C₂H₆O
Structure with 'alcohol' -OH functional group
CH₃-CH₂-OH ------- ethanol
Structure with ether functionality:
H₃C-O-CH₃ ---------dimethyl ether
Two cups of the same size are filled to the brim with clear liquids. Only one container holds water. The other contains a liquid that has greater density than water. How could you safely identify the container holding the water? A) See which cup feels heavier. B) Taste the liquid in both cups. C) Touch the liquid in both cups. D) Add salt to the liquids to see if it dissolves.
Answer: A) See which cup feels heavier.
Explanation:
Density is defined as the mass contained per unit volume.
[tex]density=\frac{mass}{volume}[/tex]
Thus if a liquid is more denser than water, it contains more mass per unit volume and thus feel heavier.
We cannot taste or touch liquids as the liquid can be corrosive.
Both the liquids can be polar and thus both can dissolve ionic compound i.e salt in it.
Thus the other liquid that has greater density than water feels heavier than water.
The atomic number of nitrogen is 7. How many protons, neutrons, and electrons make up an atom of Nitrogen-15?
A nonpartisan iota of Nitrogen has a mass of 18. There are 7 protons in the core of this iota. What number of neutrons, complete electrons, and valence electrons are available
Nitrogen 15 has a nuclear mass of 15. The mass number is # protons in addition to # of neutrons, so for N-15 mass is 15 and the protons are dependably 7 so there must be 15-7=8 neutrons. N-15 has 7 electrons since it has 7 protons and p = e.
2.1 x10^3 + 2.1 x 10^2
what are all of the elements that end with F electrons
The elements whose electron configurations end with f electrons are in the Lanthanide and Actinide series: those long series at the bottom of the Periodic Table (see image).
The atoms are adding electrons into f orbitals, but the f electrons are not always the last electrons in the electron configuration.
For example, the electron configuration of Eu is [Xe]6s²4f⁷, but that of Gd
is [Xe] 6s²4f⁷5d.
I have blocked off in red all the exceptions like Gd.
What are the two main types of luster? A. dense and porous B. coarse and smooth C. metallic and nonmetallic D. striated and non-striated
The answer is metallic and nonmetallic.
Answer:
The answer is C. Metallic and Non-metallic.
Explanation:
Luster is a physical property that shows how light acts on the surface of a material and how it is reflected in it. The main types of brightness are:
Metallic shine = This type of shine occurs in metals, since they are very opaque and whose surface has a lustrous appearance, that is, it totally reflects light.Non-metallic shine = This type of shine is presented in minerals with a light color, produced by transparent substances, such as the diamond.The development of the cell theory involved ___________________________. A. different ideas from different scientists. B. the efforts of one scientist. C. work with computer models. D. complete agreement among scientists. The invention of the microscope made it possible for scientists to _________ A. create new types of cells. B. examine and describe cells. C. copy genetic material. D. develop unique chemicals. Which cell part contains directions for cell growth and reproduction? A. cell wall B. plasma membrane C. nucleus D. pores
1. Different ideas from different scientists (such as schleiden and schwann)
2. B. Describe and examine cells
3. Sorry i don't remember this
hope this helps :)
Final answer:
The development of the cell theory was a collaborative effort by different scientists, including Schleiden, Schwann, and Virchow, and the invention of the microscope allowed for cells to be examined and described, making 'A. different ideas from different scientists' and 'B. examine and describe cells' the correct answers for the respective questions. The nucleus contains directions for cell growth and reproduction, so 'C. nucleus' is the correct answer for the third question.
Explanation:
The development of cell theory involved different ideas from different scientists. Scientists like Schleiden, Schwann, and Virchow contributed to the theory that all organisms are made of cells, all life functions occur within cells, and all cells come from other cells. Hence, the correct answer to the first part of the question is A. different ideas from different scientists.
The invention of the microscope, including the advanced electron microscope in the 1950s, allowed scientists to examine and describe cells. They were able to see organelles and other structures inside cells for the first time. Therefore, the answer to the second part of the question is B. examine and describe cells.
As for the cell part containing directions for cell growth and reproduction, the correct answer is C. nucleus. The nucleus of a cell contains DNA, which holds the hereditary material and instructions for cell growth, function, and reproduction.
What is the chemical formila for monosaccharides?
Final answer:
The chemical formula for monosaccharides is CnH2nOn, where n can be any number greater than two. Glucose, a common monosaccharide, has a molecular formula of C6H12O6. Monosaccharides can exist as linear chains or as ring-shaped molecules, with glucose having two different arrangements of the hydroxyl group in its ring form.
Explanation:
The chemical formula for monosaccharides is CnH2nOn, where n can be any number greater than two. For example, glucose, a common monosaccharide, has a molecular formula of C6H12O6.
Monosaccharides can exist as linear chains or as ring-shaped molecules. In-ring forms, glucose can have two different arrangements of the hydroxyl group (OH) around the anomeric carbon. If the hydroxyl group is below carbon number 1 in the sugar, it is in the alpha (α) position, and if it is above the plane, it is in the beta (β) position.
The ring-forming reaction between the hydroxyl group and the carbonyl group occurs at carbon number 1, which is the anomeric carbon.
Is cooking raw tomatoes a physical or a chemical change?
Explain why?
When you are asked a question like this, you can always ask yourself this question. Can I change it back after this change? For example, if you are burning wood, you cannot bring it back to wood after you burn it, therefore, it is a chemical change. However, if you boil and evaporate water, you can make the water condense again back into its liquid form. In this case, you cannot bring the tomato back to its raw state. Therefore, cooking raw tomatoes is a chemical change.
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 the atom loses 2 electrons, the net charge on the atom will be 2+
If the atom gains 4 electrons, the net charge on the atom will be 4-
Explanation:
An atom is smallest unit of a matter or substance.It consist of three subatomic particles : electrons, protons, neutrons.
Protons are positively charged, neutrons are neutral and both are located in nucleus where mass of an atom is concentrated.
Electrons are negatively charged and are located outside the nucleus where they orbit in different energy levels around the nucleus.
In an atom, when electrons are lost, the atom gains a positive charge and forms cation. In an atom, when electrons are gained, the atom occupies a negative charge and forms anion.
Thus an atom with 9 electrons and 9 protons will be electrically neutral.
On losing 2 electrons, there will be 7 electrons and 9 protons will have 2+ charge.On gaining 4 electrons, there will be 13 electrons and 9 protons will have 4- charge.
A copper coin with a mass of 6.30 grams changes temperature in the sunshine from 20.0°C to 32.0°C. How much energy is transferred? The specific heat capacity of copper is 0.377 joules/gram degree Celsius. Express your answer to three significant figures.
The energy transferred is 28.5 j
calculation
energy is calculate MCΔT formula where,
M(mass)= 6.30 grams
C(specific heat capacity)= 0.377 j/g
ΔT(change in temperature)= 32.0c- 20 c= 12 c
Energy is therefore= 6.30 g x 0.377 j/g /c x 12 c =28.5 j
The energy transferred is 28.5 j.
Pb + PbO2 + 2H2SO4 2PbSO4 + 2H2O How many moles of water are produced if 5.43 mol PbO2 are consumed?
5.43 times 2 = 10.86
10.9 is your answer.
Answer: 10.86 moles
Explanation: For the given chemical reaction. 2 moles of lead combines with 2 moles of lead oxide and 2 moles of sulphuric acid to produce 2 moles of lead sulphate and 2 moles of water.
[tex]Pb+PbO_2+2H_2SO_4\rightarrow 2PbSO_4+2H_2O [/tex]
1 mole of lead oxide [tex](PbO_2)[/tex] produces 2 moles of water[tex](H_2O)[/tex]
Thus 5.43 moles of lead oxide [tex](PbO_2)[/tex] produces =[tex]\frac{2}{1}\times 5.43=10.86[/tex] moles of water[tex](H_2O)[/tex]
If we removed the producers from this food web, how would it affect the balance of the ecosystem?
There would be a decrease in consumers and decomposers.
There would be an increase in primary consumers and a decrease in secondary consumers.
There would be a decrease in primary consumers and an increase in secondary consumers.
There would be an increase in consumers and decomposers.
There would be a decrease in consumers and decomposers.
Removing producers would slowly but surely cause the entire food web to tumble. With this in mind - we can say that the answer is A (There would be a decrease in consumers and decomposers) - because everything will lessen with the removal of producers.
Select the correct answer.
A weather station predicts that warm, humid air will pass over much cooler land during the early morning hours. Which precaution should the weather station give to residents who are driving to work that morning?
A.
Bring extra water because the morning will be hot and dry.
B.
Use headlights and drive slowly if you encounter dense fog.
C.
Pack raincoats and umbrellas to prepare for severe rainstorms.
D.
Plan for blizzard-like conditions by wearing snow boots and mittens.
it would be B because warm humid air+cool land=fog
Answer: B) Use headlights and drive slowly if you encounter dense fog.
Explanation: Fog begins to form when water vapor condenses into liquid water droplets that are suspended in the air. This happens when the air has a lot of moisture and when the temperature is low (because in this way the water in the air condenses). So if a weather station predicts that warm humid air will pass over much cooler land, the precaution must be to use healights and drive slowly because it will probably be dense fog.
Which of the following is a reasonable ground-state electron configuration?
1s21p62d2
1s22s42p6
1s22s22p5
1s22s22d6
Answer is: 1s22s22p5.
1) Electron configuration 1s²1p⁶2d², this is not reasonable because 1p and 2d oritals do not exist.
2) Electron configuration 1s²2s⁴2p⁶, this is not reasonable because s orbitals only contain 2 electrons.
3) Electron configuration 1s²2s²2p⁵ is of an element fluorine. Fluorine (F) has atomic number 9, which means it has 9 protons and 9 electrons.
4) Electron configuration 1s²2s²2d⁶, this is not reasonable because 2d orbitals do not exist.
Alkali metals are found in many common substances but are rarely found in pure form. Explain why this is in the case
Alkali metals are rarely found in pure form because they are so reactive.
Alkali metals are in Group 1 of the Periodic Table.
They need to lose only one valence electron to reach a filled valence shell
Thus, they readily react wirh water and other chemicals in the earth to form compounds.
How to identify a Chemical Property and a Chemical Change?
Physical properties are the traits of an object that can be readily seen such as size, color and state. Measuring or changing these properties does not affect the chemical nature of the matter. For example, a paper that is cut into small pieces has undergone a physical change. The pieces have a different quantity, size, shape and texture than the original sheet.
Chemical properties are the characteristics that describe the composition of matter. These traits are carried by each individual atom, or part of matter. Some examples of chemical properties include combustibility, flammability and reactivity. Another way to look at this is to think of the chemical properties as potentials. Dry paper has the potential to burn; this is flammability, a chemical property. Magnesium metal has the potential to combine with oxygen and form Magnesium Oxide.
A sample of gas has a mass of 827 mg . Its volume is 0.270 L at a temperature of 88 ∘ C and a pressure of 975 mmHg . Find its molar mass.
Steps:
Mw = w * R * T / p * V
T = 88 + 273 => 361 K
p = 975 mmHg in atm :
1 atm = 760 mmHg
975 mmg / 760 mmHg => 1.28 atm
Therefore:
= 0.827 * 0.0821 * 361 / 1.28 * 0.270
= 24.51 / 0.3456
molar mass = 70.92 g/mol
Answer:
The molar mass of the gas is 70.83 g/mol.
Explanation:
Mass of the gas m= 827 mg = 0.827 g
Molar mass of gas = M
Pressure of the gas = 975 mmHg = 1.28 atm
Temperature of the gas = 88^C= 361 K
Using idal gas equation:
[tex]PV=nRT[/tex]
[tex]PV=\frac{m}{M}\times RT[/tex]
[tex]M=\frac{mRT}{PV}[/tex]
[tex]M=\frac{0.827 g\times 0.0820 atm L/mol K\times 361 K}{1.28 atm \times 0.270 L}=70.83 g/mol[/tex]
The molar mass of the gas is 70.83 g/mol.
Which acid has the formula HNO2?
If it was HNO3 then it would be Nitric Acid (ic)
But it is HNO2 and that is Nitrous Acid (ous)
The less joiners is ''OUS''
The more joiners is ''IC'' .
Finally the answer is Nitrous acid.
Nitrous acid, with the formula HNO₂, is a weak acid significant in many chemical processes and cannot be isolated in pure form. It is used for the production of hydroxylamine, diazotizations, and the synthesis of various compounds such as azo dyes and drugs. Nitrous acid also forms specific coordination compounds with NO₂ acting as either a nitro or nitrito ligand.
The acid with the formula HNO₂ is known as nitrous acid. Nitrous acid is a weak acid with a pKa of 3.15 at 25°C and it cannot be isolated in pure form.
It primarily exists in aqueous solutions and is a significant reagent in various chemical processes including the production of hydroxylamine (NH₂OH), diazotization of aromatic amines, and the manufacture of azo dyes and drugs. Moreover, nitrous acid plays a role in the chemistry of coordination compounds, where NO₂ can act as a monodentate nitro (N-coordination) or nitrito (O-coordination) ligand.
Other oxoacids of nitrogen include nitric acid (HNO₃), which is also an essential acid in the chemical industry. Nitric acid is stronger than nitrous acid and is produced through the Ostwald process, which eventually oxidizes ammonia to NO₂, and subsequently to nitric acid.
Linda has two glasses of apple juice. Glass A has 40 grams of juice at 25 °C. Glass B has 40 grams of juice at 40 °C. Which of the following steps will make the kinetic energy of the molecules of the juice in both glasses equal?
In both glasses have juices of same mass. But the temperature is different due to which the kinetic energy of molecules in both glasses is different.
As kinetic energy is directly proportional to temperature.
To make the kinetic energy of the molecules equal she should:
Heat one glass of 25°C to 40°C.or
Cool the juice of 40°C to 25°CThe answer would be "C" increase glass a by 15 degrees
what volume of silver metal Will Weigh exactly 2500 .0 g the density of silver is 10.5 g/ cm3 squared
Hello!
The formula is density = mass / volume
=> volume = mass / density
volume = ?
mass = 2500.0 g
density = 10.5 g/cm3
volume = mass / density
volume = 2500.0 g / 10.5 g/cm3
volume = 2380.95 cm3
Hope this help!
The volume of silver that weighs exactly 2500.0 g is approximately 238.095 cm³, if the density of silver as 10.5 g/cm³.
To find the volume of silver that weighs exactly 2500.0 g, we use the formula for density, which is:
Density = Mass / Volume
Given the density of silver as 10.5 g/cm³, we can rearrange the formula to solve for volume:
Volume = Mass / Density
Substituting the given values:
Volume = 2500.0 g / 10.5 g/cm³
Volume ≈ 238.095 cm³
This means that a volume of approximately 238.095 cm³ of silver will weigh 2500.0 g.
Why do elements such as Neptunium, Plutonium, Californium, Einstenium, Bohrium, Flerovium, Radon, Oganesson, and a few others have half a number in parentheses at the bottom of their box on the periodic table instead of the atomic weight? Thanks! :)
All the elements you listed share a common trait: they are synthetic, radioactive elements. These elements do not have a stable isotope, so for a radioactive element, its most stable isotope's atomic mass will be listed in parentheses.
One such example would be plutonium. This element has 6 different isotopes with differing half-lives. The most stable isotope for plutonium is plutonium-244, with a half-life of around 80 million years. Therefore, the atomic mass listed for plutonium will be (244).
list two things that might spin a generator to produce electricity
electrical energy and mechanical energy