Answer:
7.52 x 10²³ molecules N
Explanation:
multiply 1.25 mol of N2 by Avogadro's Number
g Which statement concerning the structure of the atom is correct? Protons and neutrons have most of the mass and occupy most of the volume of the atom. Electrons have most of the mass but occupy very little of the volume of the atom. Electrons have most of the mass and occupy most of the volume of the atom. Protons and neutrons have most of the mass but occupy very little of the volume of the atom.
Protons and neutrons have most of the mass but occupy very little of the volume of the atom.
The statement concerning the structure of the atom is correct is Protons and neutrons have most of the mass but occupy very little of the volume of the atom. Therefore, option D is correct.
What is an atom ?Each atom is made up of a nucleus and one or more electrons that are linked to it. One or more protons and a significant number of neutrons make up the nucleus. Only the most prevalent type of hydrogen is neutron-free. Atoms that are neutral or ionized make up every solid, liquid, gas, and form of plasma.
But when it comes to the name atom, we must travel back to 400 B.C. ancient Greece. The Greek word atomos, which meaning "uncuttable," was proposed by Democritus, a renowned philosopher. In the end, all matter could be reduced to distinct, tiny particles, or atomos, he said.
The smallest unit of matter that may be divided without producing electrically charged particles is the atom.
Thus, option D is correct.
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The only sure evidence for a chemical reaction is
Answer:
that one or more new substances are produced. Temperature Changes Chemical reactions can release energy or absorb energy.
Explanation: .
A chemistry student weighs out 0.0349g of formic acid HCHO2 into a 250.mL volumetric flask and dilutes to the mark with distilled water. He plans to titrate the acid with 0.1500M NaOH solution. Calculate the volume of NaOH solution the student will need to add to reach the equivalence point. Round your answer to 3 significant digits.
the molar mass of formic acid CH2O2 = 46.03 g/mol
the number of moles of HCHO2 = 0.0349 g / 46.03 g/mol
n = 7.58 × 10^-4 mol
according to the balanced chemical equation
HCHO2 + NaOH → H2O + NaCHO2
1 mol of formic acid will react with 1 mol of NaOH
so we need 7.58 × 10^-4 mol of NaOH
the molarity = 0.1500M = 7.58 × 10^-4 mol / volume
the volume = 7.58 × 10^-4 mol / 0.1500M
= 5.05 × 10^-3 L = 5.05 ml
Andrew walks through his garden and observes that the shapes of dewdrops are not always the same. Suppose he wants to investigate using the scientific method. Which questions are testable questions that he can ask to look into the reasons for the different shapes? PLEASE HELP LOTS OF POINTS AND BRAILIEST
Answer:
A scientific method is the one which is independent of the person taking the measurements. Hence, a method which includes a scientific instrument/experiment, systematic observation, measurement, testing etc and is independent of personal feelings or opinions is known as a scientific method.
The measurement of temperature, testing of the material of surface, and moisture content in the atmosphere are testable questions and part of scientific method to find the reasons of different shapes of dewdrops. whether the different shapes are formed due to change in temperature, surface or moisture content in the atmosphere or not? The result of this measurement would not depend on the scientist doing the experiment. Scientific instruments would be used which would give the same reading. But the result of the observation of most unusual shape and pleasing shape of drop is purely dependent on one observer. It cannot be generalized reason
Explanation:
Answer:
brainliest pls pls pls
Explanation:
Chemicals that control weeds are called
A. acaricides.
B. herbicides.
C. insecticides.
D. pesticides.
Answer:
The answer is D
Explanation:
because insecticides are used for insects but pesticides are used to kill off unwanted plants
Answer:
B. herbicides
Explanation:
it kills weeds.
Balanced or Unbalanced
CH4+4CI2=CCI4+4HCI
Answer:
Balanced Chemical Equation
CH4 + 4Cl2 → CCl4 + 4HCl
Explanation:
Brainliest please?
Which of the following statements is true?
Question 10 options:
a chromosome is larger than a cell
a DNA strand is made of many chromosomes
a gene contains may chromosomes
a chromosome contains many genes
Answer:
a chromosome contains many genes
Explanation:
An aqueous solution of calcium hydroxide is standardized by titration with a 0.112 M solution of hydrobromic acid. If 15.2 mL of base are required to neutralize 12.4 mL of the acid, what is the molarity of the calcium hydroxide solution?
Answer:
0.0457 M
Explanation:
The reaction that takes place is:
2HBr + Ca(OH)₂ → CaBr₂ + 2H₂OFirst we calculate how many moles of acid reacted, using the HBr solution's concentration and volume:
Molarity = Moles / VolumeMolarity * Volume = Moles0.112 M * 12.4 mL = 1.389 mmol HBrNow we convert HBr moles to Ca(OH)₂ moles, using the stoichiometric ratio:
1.389 mmol HBr * [tex]\frac{1mmolCa(OH)_{2}}{2mmolHBr}[/tex] = 0.6944 mmol Ca(OH)₂Finally we calculate the molarity of the Ca(OH)₂ solution, using the given volume and calculated moles:
0.6944 mmol Ca(OH)₂ / 15.2 mL = 0.0457 Mif the heat of fusion of ethonal is 0.1 kj/g and the heat of vaporization of ethonal is 0.9 kj/g how much heat is needed to melt 10 g of ethanol?
Heat needed to to melt 10 g of ethanol : 1 kJ
Further explanationThe heat to change the phase can be formulated :
Q = mLf (melting/freezing)
Q = mLv (vaporization/condensation)
Lf=latent heat of fusion
Lv=latent heat of vaporization
mass of ethanol= 10 g
Heat needed to melt :
[tex]\tt Q=m\times L_f\\\\Q=10~g\times 0.1~kJ/g\\\\Q=\boxed{\bold{1~kJ}}}[/tex]
A metal ion uses d2sp3 orbitals when forming a complex. What is its coordination number and the shape of the complex?
Answer:
Octahedral
Explanation:
The idea of hybridization is a valence bond concept introduced by Linus Pauling and soon became an important explanation for the structure of molecules even in coordination chemistry.
Hybridization involves the mixing of orbitals of appropriate energy to form a new set of orbitals that are more suitable for bonding with ligands.
When one s, two d and three p orbitals are hybridized in complex formation, octahedral complexes are formed.
How many atoms are in 2.37 moles of Krypton
Answer:
1.43 × 10²⁴ atoms Kr
General Formulas and Concepts:
Chemistry - Atomic Structure
Using Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
2.37 mol Kr
Step 2: Convert
[tex]2.37 \ mol \ Kr(\frac{6.022 \cdot 10^{23} \ atoms \ Kr}{1 \ mol \ Kr} )[/tex] = 1.42721 × 10²⁴ atoms Kr
Step 3: Check
We are given 3 sig figs. Follow sig fig rules and round.
1.42721 × 10²⁴ atoms Kr ≈ 1.43 × 10²⁴ atoms Kr
Can someone answer 3’for me please?
Why can’t straw be made into gold
if there are no gold atoms in straw, then no chemical process can turn straw into gold since it would mean that new gold atoms are being "made," which would be against Dalton's idea.
What are gold atoms in straw?The first thing we must keep in mind is the axiom of Dalton's atomic theory, which states that atoms cannot be formed nor destroyed. It is obvious that atoms in the molecules of the reactant and product must be rearranged during chemical reactions.
It is clear that there are no gold atoms in the straw because it is composed of carbon, hydrogen, and oxygen atoms.
Therefore, if there are no gold atoms in straw, then no chemical process can turn straw into gold since it would mean that new gold atoms are being "made," which would be against Dalton's idea.
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There are no self-sustaining fusion reactors operating in the world because there is currently a lack of:____________.
A) a way to achieve the extremely high temperatures needed for a fusion reaction
B) a method to dispose of the waste produced by fusion reactions
C) a way to contain fusion reactions
D) materials that will participate in fusion
Answer:
b is the correct answer....
To solve such this we must know the concept of fusion reactions. Therefore, the correct option is option B that is a method to dispose of the waste produced by fusion reactions.
What is chemical reaction?Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved.
Fusion processes, which convert protons into heavier elements, are the source of energy generation in stars. They are also a possible source of energy for contemporary industrial society. The transformation of hydrogen to helium is the primary source of energy in stars. There are no self-sustaining fusion reactors operating in the world because there is currently a lack of a method to dispose of the waste produced by fusion reactions.
Therefore, the correct option is option B.
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c. What might have happened in Kush and Egypt if Kush had developed iron
weapons?
Answer:
Kush would have been able to fight better and probably would have never been invaded by Egypt, and they could have beaten the Assyrians when they tried to takeover Egypt. And the 25th dynasty would have continued.
Explanation:
that is my explanation and answer^
Calculate ΔH° = for the chemical reaction
Cl2(g) + F2(g) --->2ClF(g)
Bond Energies, kJ mol-1
F---F 159
Cl--Cl 243
Cl--F 255
Answer: [tex]\Delta H^0[/tex] for the reaction [tex]Cl_2(g)+F_2(g)\rightarrow 2ClF(g)[/tex] is -108kJ
Explanation:
The balanced chemical reaction is,
The expression for enthalpy change is,
[tex]\Delta H=[n\times B.E_{reactants}]-[n\times B.E{products}][/tex]
where, n = number of moles
Now put all the given values in this expression, we get
[tex]\Delta H=[1\times B.E_{Cl_2}+1\times B.E_{F_2}]-[2\times B.E_{ClF}][/tex]
[tex]\Delta H=[(1\times 243)+(1\times 159)]-[2\times 255][/tex]
[tex]\Delta H=-108kJ[/tex]
Thus [tex]\Delta H^0[/tex] for the reaction [tex]Cl_2(g)+F_2(g)\rightarrow 2ClF(g)[/tex] is -108kJ
The list identifies various properties of four elements:
Element 1 is a gas at room temperature.
Element 2 is a solid which conducts electricity.
Element 3 is a gas with an effective nuclear charge of +7.
Element 4 is malleable and can take the form of a shiny solid sheet.
Based on this list, which elements are metals?
A. Elements 1 and 3
B. Elements 1 and 4
C. Elements 2 and 3
D. Elements 2 and 4
Answer: D
Explanation: I guessed it and got it right
A fundamental object that is difficult to divide into smaller bits is known as an element. Therefore option D is correct.
What is element ?An element is a species of atoms, including the pure material made entirely of that species, that have a specific number of protons in their nuclei. Chemical elements, in contrast to chemical compounds, cannot be reduced by any chemical process into simpler molecules.
An element is a material that cannot be broken down by non-nuclear processes in chemistry and physics. A discrete component of a larger system or collection is referred to as an element in computers and mathematics.
Metals, nonmetals, and metalloids are the Periodic Table's three main groupings. Each group's constituent elements share comparable physical and chemical characteristics. Among the physical characteristics used to separate the three groups are, A substance's capacity to reflect light is referred to as luster.
Thus, option D is correct.
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During homogeneous catalysis, if a catalyst is present in the liquid phase, which phase must the reactants be in?
Answer:
The reactants must be in the liquid phase.
Explanation:
Homogeneous means that something is of the same nature.
In the context of catalysis, it means that the catalyst and the reactants are in the same phase.
If the catalyst is in the solid phase, the reactants are solids are well.
If the catalyst is in the liquid phase, then the reactants are also in the liquid phase.
And so on.
Which model of the solar system is shown here?
Answer: C
Explanation: hope this helps
The model of the solar system that is shown here is:
C. Geometric model
Model for description of earth and other entites
Geometric model:In astronomy, the geocentric model is a superseded description of the Universe with Earth at the center. Under the geocentric model, the Sun, Moon, stars, and planets all orbit Earth.
Characteristics:
the Earth is the focal point of the universe and it is fixed,the planets, the Sun, and the stars spin around the Earth,the circle and the circle are "awesome" shapes, so all movements overhead ought to follow roundabout ways, which can be credited to objects being appended to circular shells.Thus, option C is correct.
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Which scenario is likely to result in the most diverse offspring?
1 point
Sexual reproduction between two individuals from different continents
Sexual reproduction between two individuals in the same population
Asexual reproduction by binary fission
Asexual reproduction by budding
Answer: i think it is binary fission
Explanation:
WILL BRAINLIEST !!
Which of the following transitions produces light with the longest wavelength?
A. 2—>1
B. 3—>1
C. 4—>2
D. 4—>3
If 27.3% of a sample of silver-112 decays in 1.52 hours, what is the half-life (in hours to 3 decimal places)?
Answer: The half life of the sample of silver-112 is 3.303 hours.
Explanation:
All radioactive decay processes undergoes first order reaction.
To calculate the rate constant for first order reaction, we use the integrated rate law equation for first order, which is:
[tex]k=\frac{2.303}{t}\log \frac{[A_o]}{[A]}[/tex]
where,
k = rate constant = ?
t = time taken = 1.52 hrs
[tex][A_o][/tex] = Initial concentration of reactant = 100 g
[A] = Concentration of reactant left after time 't' = [100 - 27.3] = 72.7 g
Putting values in above equation, we get:
[tex]k=\frac{2.303}{1.52hrs}\log \frac{100}{72.7}\\\\k= 0.2098hr^{-1}[/tex]
To calculate the half life period of first order reaction, we use the equation:
[tex]t_{1/2}=\frac{0.693}{k}[/tex]
where,
[tex]t_{1/2}[/tex] = half life period of first order reaction = ?
k = rate constant = [tex]0.2098hr^{-1}[/tex]
Putting values in above equation, we get:
[tex]t_{1/2}=\frac{0.693}{0.2098hr^{-1}}\\\\t_{1/2}=3.303hrs[/tex]
Hence, the half life of the sample of silver-112 is 3.303 hours.
The electron configuration for an element is 1s2 2s2 2p6 3s2 3p6. What is the atomic number of the element? *
A. 3
B. 11
C. 18
D. 22
Explanation:
Electronic configuration =
1s² 2s² 2p⁶ 3s² 3p⁶
Atomic number = 18Element = ArgonSymbol = ArGroup = 18period = 3Therefore,
Option C is correct✔
According to the electronic configuration, the atomic number of the element is 18.
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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How many moles are in the 100,000g of CuSO4 • 5H2O ?
Answer:
try (107.87 amu)
Explanation:
A metal is found that has a mass of 27g and will displace 6mL of water. Calculate its density and identify the metal.
The density of metal = 4.5 g/ml, and the metal = Titanium
Further explanationDensity is a quantity derived from the mass and volume
Density is the ratio of mass per unit volume
Density formula:
[tex]\large {\boxed {\bold {\rho ~ = ~ \frac {m} {V}}}}[/tex]
ρ = density
m = mass
v = volume
mass of metal=27 g
volume = 6 ml
The density :
[tex]\tt \rho=\dfrac{27}{6}\\\\\rho=4.5~g/ml[/tex]
The metal with a density of 4.5 g/ml is Titanium
PLEASE HELP I WILL GIVE BRAINLIEST!!!!!
What is a main difference between a mixture and a pure substance?
OAmixture is only a liquid, but a pure substance can be in any state.
OAmixture looks the same throughout, but a pure substance does not.
OAmixture can vary in composition, but a pure substance has a set composition.
O Amixture can be made up of a single compound, but a pure substance cannot
Answer:
I think the answer is c!
Explanation:
Pure substances are further broken down into elements and compounds. Mixtures are physically combined structures that can be separated into their original components. A chemical substance is composed of one type of atom or molecule. hope this helps you!
Cant figure this out
Which is stronger, the strong force (SF) or the electromagnetic force (EMF)? Describe how they battle each other in the nucleus. What would happen if their strengths were reversed?
Answer:uclear Force that holds together the nucleus of an atom. electromagnetic force. ... They are unstable because the Strong Force that would hold them together if the protons and neutrons were closer is weakened because the protons and neutrons get too far apart.
Explanation:
Calculate the molar mass of Ga(NO3)3
255.732 g/mol
159.738 g/mol
227.718 g/mol
131.727 g/mol
Answer:
255.732 g/mol
Explanation:
Molar mass of Ga(NO3)3 = 255.7322 g/mol. This compound is also known as Gallium(III) Nitrate.
If 6.63 g of CuNO3 is dissolved in water to make a 0.140 M solution, what is the volume of the solution in milliliters?
Answer:
377mL is the volume of the solution
Explanation:
A 0.140M solution of CuNO₃ contains 0.140 moles of CuNO₃ per liter of solution. Thus, we need to convert first the mass of CuNO₃ to moles using its molar mass and, with the moles available, we can find the volume of the solution, thus:
Moles CuNO₃ -Molar mass: 125.55g/mol:
6.63g * (1mol / 125.55g) = 0.0528 moles of CuNO₃.
Volume of solution:
0.0528 moles of CuNO₃ * (1L / 0.140 moles CuNO₃) = 0.377L
0.377L * (1000mL / 1L) =
377mL is the volume of the solution