All solutions are mixtures of two or more substances, but unless the mixture has a homogeneous distribution of solutes in the solvent, then the mixture is not a solution. Therefore, all mixtures are not solutions.
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Geometric model:In astronomy, the geocentric model is a superseded description of the Universe with Earth at the center.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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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
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: .
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:
4. Look at the equation below and determine what fitsI in the empty box.
14 C --> 4 N+
?
re
c. en TH
What belongs in the empty box?
A.
В.
e
D.
Answer:
Beta particles
Explanation:
A beta emission is said to occur when a neutron is converted into a proton. When a beta emission takes place, the daughter nucleus increases it's atomic number by 1. A neutrino is also produced.
Since the mass number remain the same but the daughter nucleus has it's atomic number increased by 1, then the particle is a beta particle.
You want to calculate the average atomic mass of a sample of Nickle. There are 32 atoms of Nickle-60 and 89 atoms of Nickle-57.
What is the percent distribution of Nickle-60?
What is the percent distribution of Nickle-57?
What is the average atomic mass of the sample? Round to the correct number of decimals and include units?
Answer:
Average atomic mass = 57.79 amu
Percent contribution of Ni-60 = 26.45%
Percent contribution of Ni-5 = 73.55%
Explanation:
Given data:
Number of atoms of Ni-60 = 32
Number of atoms of Ni-57 = 89
Percent distribution of both isotopes = ?
Average atomic mass of sample = ?
Solution:
Percent contribution:
Total number of atoms = Ni-60 + Ni-57
Total number of atoms = 32 +89 = 121
Percent contribution of Ni-60 = 32/121×100
= 26.45%
Percent contribution of Ni-57 = 89/121×100
= 73.55%
Average atomic mass:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (26.45×60)+(73.55×57) /100
Average atomic mass = 1587 + 4192.35 / 100
Average atomic mass = 5779.35 / 100
Average atomic mass = 57.79 amu.
Electron transfer between redox centers in proteins is controlled by quantum tunneling. We can model the region between two redox centers as an energy barrier which the electron must cross. If the distance between the redox centers is 0.681 nm and the energy of the electron is 0.5540.554eV lower than the height of the barrier, what is the probability that the electron will successfully cross to the next redox center
Answer:
5.61 e⁻³
Explanation:
Given that:
The barrier length = 0.681 nm = 6.81 × 10⁻¹⁰
The difference between the height of the barrier & the energy of the electron is;
[tex]V - E = 0.554 \ eV (1.6 \times 10^{-19} )[/tex]
= 8.864 × 10⁻²⁰ V
where;
m = 9.1 × 10⁻³¹ kg
The probability[tex]P = e^{-2 \ kd}[/tex]
[tex]k = 2 \pi \sqrt{\dfrac{2m (V-E)}{h^2} }[/tex]
[tex]k = 2 \pi \times \dfrac{\sqrt{2 \times 9.1 \times 10^{-31} \times 8.864 \times 10^{-20}}}{6.63 \times 10^{-34}}[/tex]
k = 3.806 × 10⁹
[tex]P = e^{-2 \ kd}[/tex]
[tex]P = e^{2 \times 3.806 \times 10^9 \times 6.81 \times 10^{-10}}[/tex]
P = 0.005606
P = 5.61 × 10⁻³
P = 5.61 e⁻³
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
Can someone answer 4 for me please?
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:
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.
Percent yield is very important in terms of money. The higher the percent yield, the more of a product you can make. If you are working for a drug company and your theoretical yield is 120 kg, but you actually made 105 kg, what is your percent yield?
A. 8.75%
B. 114%
C. 87.50%
D. 15.00%
Answer:
87.5 %
Explanation:
Step 1: Given data
Theoretical yield: 120 kgReal yield: 105 kgStep 2: Calculate the percent yield
When working with chemical reactions, we can determine the efficience in obtaining a product measuring the percent yield. The theoretical yield is the maximum amount of product that we could obtain according to the stoichiometry, whereas the real yield is the amount of product that we actually obtain when we carry out the process. We can calculate the percent yield usign the following expression.
%yield = real yield / theoretical yield × 100%
%yield = 105 kg / 120 kg × 100%
%yield = 87.5 %
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.
A student is looking for an element to react with lithium to create the most vigorous reaction possible. To which direction on the periodic table should the student look?
A. Lower left
B. Upper left
C. Lower right
D. Upper right
Answer:
D. Upper right
Explanation:
The position the student should look for such element is in the upper right corner before the noble gases.
Specifically, the group of halogens will react vigorously with lithium.
Lithium is an electropositive metal. To attain stability, it must lose an electron. The group of halogens are a series of highly electronegative elements. They have 7 electrons in their outer shell and requires just one more to complete their octet. Therefore, they combine violently with halogensHalogens are found in the upper right corner on the periodic table.Answer:
D. Upper right
Explanation:
I had the exact same question
At what temperature is water a gas
Answer:
212 degrees Fahrenheit
Explanation:
When liquid water reaches a low enough temperature, it freezes and becomes a solid—ice. When solid water is exposed to enough heat, it will melt and return to a liquid. As that liquid water is further heated, it evaporates and becomes a gas—water vapor.
The red outlined elements have what major characteristics in common?
1 point
Metals, Nonmetals, and Metalloids
One major characteristic they have in common is they are metals.
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:
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.
A molecule has a molar mass of 22.45 g/mol. What is the mass of 4.12*10^24 of the molecules?
Answer:
153.56g
Explanation:
Number of moles = mass/molar mass
To get the number of moles of the molecule, we divide the number of molecules contained by Avagadro's number, which is 6.02 × 10^23 molecules.
moles = 4.12 × 10^24 ÷ 6.02 × 10^23
number of moles = 0.684 × 10^(24-23)
number of moles = 0.684 × 10^(1)
number of moles = 6.84mol
If the molar mass of the molecule is 22.45 g/mol, the mass of the molecule can be calculated thus:
mass = moles × molar mass (MM)
mass = 6.84 × 22.45
mass = 153.558
mass = 153.56g
How high of a Frequency would a photon have to be for it to have an energy of 4 joules
The frequency of photon=6.03 x 10³³ /s
Further explanationRadiation energy is absorbed by photons
The energy in one photon can be formulated as
[tex]\large{\boxed{\bold{E\:=\:h\:.\:f}}}[/tex]
Where
h = Planck's constant (6,626.10⁻³⁴ Js)
f = Frequency of electromagnetic waves
Energy of photon = 4 J
So the frequency :
[tex]\tt f=\dfrac{E}{h}\\\\f=\dfrac{4}{6.626.10^{-34}}\\\\f=6.03.10^{33}/s[/tex]
What is electron affinity?
Answer:
The ability of an atom to accept an electron.
Explanation:
Electron affinity is measured by observing the energy change of a substance when an electron is added to it in its neutral gas form. For example, elements that are on the far right of the periodic table (excluding noble gases) are more likely to accept electrons rather than give them up. This is why Fluorine has the highest electron affinity of all atoms on the periodic table.
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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!
The combustion of ethyne, shown below unbalance, produces heat which can be used to weld metals:
C2H2 (g) +502 (g) →2CO: (g) +H20 (g) AH reaction= -1544kJ
How much ethyne gas (in g) would you need to react with excess oxygen according to this reaction in order to raise the temperature of 325 g of high carbon steel from 165'C to its melting point, 1540 C? The heat capacity of high carbon steel is 0.490 J/g'C. (Assume a complete reaction and that all heat is transferred from the reaction to the metal with no loss.)
a. 7.37g
b. 1.84 g
c. 4.13 g
d 3.69 g
Answer:
3.69 g
Explanation:
Given that:
The mass m = 325 g
The change in temperature ΔT = ( 1540 - 165)° C
= 1375 ° C
Heat capacity [tex]c_p[/tex] = 0.490 J/g°C
The amount of heat required:
q = mcΔT
q = 325 × 0.490 × 1375
q = 218968.75 J
q = 218.97 kJ
The equation for the reaction is expressed as:
[tex]C_2H_{2(g)} + 5O_{2(g)} \to 2CO_{2(g)} + H_2O_{(g)} \ \ \ \ \ \Delta H^o_{reaction} = -1544 \ kJ[/tex]
Then,
1 mole of the ethyne is equal to 26 g of ethyne required for 1544 kJ heat.
Thus, for 218.97 kJ, the amount of ethyne gas required will be:
[tex]= \dfrac{26 \ g}{1544 \ kJ} \times 218.97 \ kJ[/tex]
= 3.69 g
What is the molarity of a NaOH solution if 28.2 mL of a 0.355 M H2SO4 solution is required to neutralize a 25.0-mL sample of the NaOH solution?A) 0.801B) 0.315C) 0.629D) 125E) 0.400
Answer:
A) 0.801
Explanation:
The reaction that takes place is:
2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂OFirst we calculate the H₂SO₄ moles that reacted:
0.355 M * 28.2 mL = 10.011 mmol H₂SO₄Now we convert H₂SO₄ moles to NaOH moles:
10.011 mmol H₂SO₄ * [tex]\frac{2mmolNaOH}{1mmolH_2SO_4}[/tex] = 20.022 mmol NaOHFinally we calculate the molarity of the NaOH solution:
20.022 mmol NaOH / 25.0 mL = 0.801 MSo the answer is option A.
The molarity of the NaOH solution used in the neutralization reaction has been 0.801 [tex]\rm \times\;10^-^3[/tex] M. Thus, option A is correct.
The neutralization reaction has resulted in the formation of the salt and water on reacting an acid with a base. In the neutralization reaction, the strength of acid and base can be given as:
[tex]\rm 2\;NaOH\;+\;H_2SO_4\;\rightarrow\;Na_2SO_4\;+\;H_2O[/tex]
For the neutralization of 1 mole of sulfuric acid, 2 moles of NaOH has been required.
The moles of sulfuric acid can be given as:
Moles = Molarity × Volume
Given, the molarity of acid ([tex]\rm H_2SO_4[/tex]) = 0.355 M
Volume of acid = 28.2 ml = 0.0282 L
Volume of base (NaOH) = 25 ml = 0.025 L
Moles of [tex]\rm H_2SO_4[/tex] = 0.355 × 0.0282 mol
Moles of [tex]\rm H_2SO_4[/tex] = 10.011 mol.
Since, 1 mole [tex]\rm H_2SO_4[/tex] = 2 moles NaOH
10.011 moles [tex]\rm H_2SO_4[/tex] = 10.011 × 2 moles NaOH
10.011 moles [tex]\rm H_2SO_4[/tex] = 20.022 moles NaOH.
The neutralization of 0.355 M [tex]\rm H_2SO_4[/tex] requires 20.022 moles NaOH. The strength of the NaOH solution will be:
Molarity = [tex]\rm \dfrac{Moles}{Volume\;(L)}[/tex]
Molarity of NaOH = [tex]\rm \dfrac{20.022}{0.025}[/tex]
Molarity of NaOH = 0.801 [tex]\rm \times\;10^-^3[/tex] M.
The molarity of the NaOH solution used in the neutralization reaction has been 0.801 [tex]\rm \times\;10^-^3[/tex] M. Thus, option A is correct.
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Balanced or Unbalanced
CH4+4CI2=CCI4+4HCI
Answer:
Balanced Chemical Equation
CH4 + 4Cl2 → CCl4 + 4HCl
Explanation:
Brainliest please?
Based on the activity series provided, which reactants will form products? F > Cl > Br > I CuI2 + Br2 Right arrow. Cl2 + AlF3 Right arrow. Br2 + NaCl Right arrow. CuF2 + I2 Right arrow.
Answer: Cul2 + Br2 ->
Explanation:
Answer:
i believe the answer is a
Explanation:
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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A student makes observations of a tree in a nearby forest. Which of the following observations of the
tree's characteristics would be useful in determining its identity with a dichotomous key?
A
It contains the nests of several birds.
B
Its leaves are long and narrow.
с
Its branches were recently cut.
D
It provides shade for ground brush.
The observations of the tree's characteristics would be useful in determining its identity with a dichotomous key is its leaves are long and narrow. The correct option is B.
What is an observation?Observation is a process of recognizing and recording an event or fact that frequently involves measuring it with tools. Recognizing and recording an event, or fact frequently involves measuring with tools. Field notes are written observations made while participating in field observations or immediately afterward.
They are crucial for understanding phenomena that have been seen in the field. Field notes frequently take the form of scratch notes, diaries, and notebooks. In the scientific field, observation is a crucial step.
Therefore, the correct option is B. Its leaves are long and narrow.
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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 M
Latitude plays a major role in determining the climate, or long-term weather patterns, of an area. Because of
differences in the intensity of solar energy, climates in higher latitudes are generally colder than climates in lower
latitudes. What causes some areas of Earth to receive less intense solar energy than others?
A) the mass of the Earth
B) the curve of the Earth
the density of the Earth
D the elevation of the Earth
Answer: D
Explanation: because the earth is slanted and at the north and south pole do not get that much sunlight so that makes it colder than most places on earth