combination of elements on the periodic table to create a substance. so I think I understand about this okay but I have a 98% on that type of subject
Match the element with its number of valence electrons. Match Term Definition: Helium Aluminum Fluorine Sodium A) 1 B) 2 C) 3 D) 7
Helium- 2
Aluminum- 3
Fluorine- 7
Sodium- 1
Hope I helped.
The correct match of each element with its valence electron is as follows:
Helium: 2 (option B). Aluminum: 3 (option C).Fluorine: 7 (option D).Sodium: 1 (option A). What is valence electron?Valence electron is any of the electrons in the outermost shell of an atom capable of forming bonds with other atoms.
The number of valence electrons possessed by the atoms of an element determines the chemical reactivity of such element and it's groups on the periodic table.
According to this question, the appropriate valence electron has been assigned to each element based on their group on the periodic table.
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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]
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.
calculate molarity of 0.50 mol of LiNO3 in 6.50 L of solution
molarity (M) = mol / Liters
molarity = ?
mol of LiNO3 = 0.50 mol
Volume = 6.50 L
molarity = 0.50 mol / 6.50 L
molarity = 0.0769 mol/L
Hope this help!
Molarity is calculated by taking the ratio of no. of moles of solute to the volume of solution in liter. The molarity of the solution containing 0.50 mol of the solute in 6.50 L of solution is 0.07 M.
What is molarity?Molarity is a term used to represent the concertation of a solution. Mathematically it is the ratio of no. of moles of solute to the volume of solution in liters.
Given that the no. of moles of solute is 0.50 and the volume is 6.50 L. Molarity of this solution is calculated as follows;
Molarity = no.of moles/ volume in L
= 0.50 mol / 6.50 L
= 0.07 mol/L
Hence, molarity of the given solution is 0.07 molar.
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Which statements accurately describe stars? Check all that apply.All stars are smaller than the Sun.
Stars are flat circles.
Stars are made of gas.
Star color is related to temperature.
Star brightness depends on shape. need help asap
Answer:
Stars are made of gas.
Star color is related to temperature.
Explanation:
Stars are big ball of gases mainly hydrogen and helium. Stars can be bigger than sun or smaller. They appear as flat circles but are spheres. The brightness of star depends on their size and distance but not on their shape. Color of star is related to temperature. A blue color star is hotter than a yellow star. A red star is a cool star.
Stars are made of gas.Star color is related to temperature.
Stars can have bigger size or small than sun Stars are normally appear as flat circles and not sphere
The brightness does not depends on their shape, it depends on the distance they are as well as their size There is a relationship between the color of star and the temperature. A yellow star is less hotter compare with blue star whereas red star is very cool star.Stars are made up of big ball of gases , these gases are mainly hydrogen and helium, the hydrogen gas are as a result of nuclear fusion.Therefore, the statement that gave accurate description about star are the second and third statement
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The quantity 44 liters expressed in cubic meters is ____.
A. 0.000 044 m3
B. 440 000 m3
C. 0.44 m3
D. 0.044 m3
Answer:
D. 0.044 m3
Explanation:
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
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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A compound has an empirical formula of CH2 and a molar mass of 70.15. What is its molecular formula?
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.
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.
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.
Which of these is a mixture carbon, carbon dioxide, air, and oxygen
Air is not a compound because oxygen and nitrogen stay seperately in air instead of reacting nitric oxide which is toxic. Same thing apply to other gases. Of course there are also few compound inside the air. However, air you breathe in generally is mixture made up of different non reacting gases and gas compounds.
mark brainliest plssss
Answer: Air is a mixture
Explanation:
Mixture is a substance which has two or more components which do not combine chemically and do not have any fixed ratio in which they are present. Example: Air
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Carbon [tex](C)[/tex] , Oxygen [tex](O)[/tex]
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: water [tex]CO_2[/tex]
Thus Air is a mixture as it is composed of various gases which are not chemically bonded.
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.
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.
Is shredding paper a physical or chemical change?
Explain why?
scientist are always learning new things. which of the following shows how scientist use observations to gain new understanding about the world?
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 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.
What is the charge of an ion that has 12 protons and 13 electrons
upon heating a copper sample will expand, leading to a lower density?
A) True
B) False
Answer;
The above statement is true
upon heating a copper sample will expand, leading to a lower density
Explanation;
-The density of solids decreased with increase in temperature and vice versa. The increase in temperature causes the volume of the solid to increase which as a result decreases the density as Density=Mass/Volume. The temperature of a body is the average kinetic energy of the molecules present in it.
In other words; The temperature of a body is the average kinetic energy of the molecules present in it. Therefore; when heat is supplied ( or temperature is increased) the average kinetic energy increases which increases the volume and thus density decreases.
Hydrochloric acid, or HCl, reacts with solid NaOH
What are the products of this chemical reaction?
Answer:
NaCI and H20
To simplify it.
Answer:
The products are NaCl and H₂O
Explanation:
The complete question is:
"Hydrochloric acid, or HCl, reacts with solid NaOH. What are the products of this chemical reaction?
HCl and NaCl
NaCl and H2O
NaOH and HCl
NaOH and H2O"
Neutralization reactions are the reactions between an acid and a base, producing salt and water. It is the type of reaction that happens in this case.
An acid and a base are strong when fully ionized, that is, in the ionization process they completely transform into positive cations or ions and negative anions or ions. So, a strong acid is an acid that completely dissociates into hydrogen ions and anions in solution.
In this case, both the HCl acid and the NaOH base are strong, completely dissociating as follows:
HCl → H⁺ + Cl⁻
NaOH → Na⁺ + OH⁻
So you have:
H⁺ + Cl⁻ + Na⁺ + OH⁻ → ?
The hydroxide anions and the hydrogen cations will neutralize each other to produce water.
H⁺ + OH⁻ → H₂O
So the sodium Na anions and Cl cations will form the NaCl salt.
Finally, the balanced chemical equation is
HCl + NaOH → NaCl + H₂O
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.
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
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 is Mendeleev most known for?
How long does it take a 180 G sample of AU-198 to decay to 1/8 it’s original mass
Answer:
8.10 days
Explanation:
The half-life of gold-198 (2.70 days) is the time it takes for half the gold to decay.
After one half-life, half (50 %) of the original amount will remain.
After a second half-life, half of that amount (25 %) will remain, and so on.
We can construct a table:
No. of half-lives Fraction remaining
1 [tex]\frac{1}{2}[/tex]
2 [tex]\frac{1}{4}[/tex]
3 [tex]\frac{1}{8}[/tex]
Thus, the gold will decay to ⅛ of its original mass after three half-lives.
∴ Time required = 3 × 2.70 days = 8.10 days
The exact time it would take for a 180 G sample of AU-198 to decay to 1/8 of its original mass depends on the half-life of AU-198, which isn't provided here. However, theoretically, it would take three half-lives for a substance to decay to 1/8 of its original mass.
Explanation:The question is asking for the time it will take for a 180 G sample of AU-198 to decay to 1/8 it's original mass. AU-198 represents gold-198, which is a radioactive isotope of gold.
In radioactive decay problems, the time it takes for a substance to decay is dependent on the half-life of the substance. Without the specific half-life of AU-198 provided, we can only describe the general formula for calculating decay time.
The half-life of a radioactive isotope is the time it takes for half of the atoms in a sample to decay. This process is exponential, meaning after each half-life, half of the remaining atoms will decay.
To decay to 1/8 of the original mass, the substance has to go through 3 half-lives (since 1/2^3 = 1/8). So, the total time it would take for a sample to decay to 1/8 of its original mass would be 3 times the half-life of this isotope.
Once you obtain the half-life value of AU-198, simply multiply it by 3 to get the answer. Remember that the unit of your answer should be in the same unit as the half-life is given.
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what is the density of mass=40g volume=20mL
Answer: The density of a substance is 2 g/mL
Explanation:
To calculate the mass of solution, we use the equation:
[tex]\text{Density of substance}=\frac{\text{Mass of substance}}{\text{Volume of substance}}[/tex]
We are given:
Mass of a substance = 40 g
Volume of a substance = 20 mL
Putting values in above equation, we get:
[tex]\text{Density of a substance}=\frac{40g}{20mL}=2g/mL[/tex]
Hence, the density of a substance is 2 g/mL
The density of a substance that has a mass of 40g and a volume of 20mL is 2g/mL.
HOW TO CALCULATE DENSITY:
The density of a substance can be calculated by dividing the mass of the substance by its volume. That is;Density (g/mL) = mass(g) ÷ volume (mL)According to this question, the mass of substance is given as 40g and a volume of 20mL. The density is calculated as follows:Density = 40g ÷ 20mLDensity = 2g/mLTherefore, the density of a substance that has a mass of 40g and a volume of 20mL is 2g/mL.Learn more at: https://brainly.com/question/2040396?referrer=searchResults
list two things that might spin a generator to produce electricity
electrical energy and mechanical energy
What is "change" when we are talking about natural and physical systems?
A.
Information that has been proven to be true
B.
Repeated processes that are used in a variety of ways
C.
A process for using knowledge and skills to acquire new knowledge
D.
A variable or alteration to one part that affects an entire system
D: is the anwser that your looking for
Answer:
A variable or alteration to one part that affects an entire system
Explanation:
Change in literal sense means the occurrence of some alteration or difference in a given object/situation/person etc.When we talk about physical and natural systems, then one can say that if a system shifts from one state to another then it has changed. The shift in the state means an alteration in its physical or chemical properties that occur in such a way that it causes a difference between the original state of the system to the final state. For example, if in a human body which is a natural system if the blood pressure drops then we can say that there is a change that took place.