Answer: C. Cold air is more dense than hot air.
Explanation: Took the test on edmentum
When a 235 92U 92235U nucleus is bombarded by neutrons (10n01n) it undergoes a fission reaction, resulting in the formation of two new nuclei and neutrons. The following equation is an example of one such fission process: 235 92U+10n→AZBa+9436Kr+310n 92235U+01n→ZABa+3694Kr+301n Enter the isotope symbol for the barium (BaBa) nucleus in this reaction. Express your answer as an isotope.
Answer:
139/56 Ba
Explanation:
In writing nuclear equations, there must be a balance of the mass and charge on both sides of the reaction equation. That is, the sum of masses on the lefthand side of the nuclear reaction equation must equal the sum of masses on the righthand side of the nuclear reaction equation. Similarly, the charges on the lefthand side of the nuclear reaction equation must equal the sum of the charges on the right hand side of the nuclear reaction equation.
Hence, the isotope of barium formed in the equation mentioned in the question is 139/56 Ba.
If you had a box that you couldn't open, how could you find out what is inside?
Answer: use you imagination
Explanation:
if you don’t know and will never know, just guess
Answer:
Shake it, imagine whats in it, or leave it alone.
How many grams (of mass m) of glucose are in 255 mL of a 5.50% (m/v) glucose solution?
Answer:
14.0 g
Explanation:
Step 1: Given data
Volume of solution (%w/v): 255 mL
Weight/volume % of glucose (solute): 5.50% (m/v)
Step 2: Calculate the mass of glucose
We can calculate the mass of glucose using the following expression.
%w/v = mass of glucose / milliters of solution × 100%
mass of glucose = %w/v × milliters of solution / 100%
mass of glucose = 5.50% (m/v) × 255 mL / 100%
mass of glucose = 14.0 g
Which of the following experimental methods cannot be used to measure the rate of a reaction?
a. measurement of the change in the partial pressure of a gas-phase reactant over time
b. measurement of the equilibrium concentration of an acidic product via titration with a strong base
c. measurement of the absorbance of a colored reactant with time
d. measurement of the absorbance of a colored product with time
e. measurement of the change in the partial pressure of a gas-phase product over time
f. none of the above can be used to measure the rate of the reaction
g. I don't know
Answer:
I think a is the best answer. but really I can not confirm that.sorry for that.
The experimental methods which cannot be used to measure the rate of a chemical reaction is: B. measurement of the equilibrium concentration of an acidic product via titration with a strong base.
A chemical reaction can be defined as a chemical process which involves the continuous transformation (rearrangement) of the ionic, atomic or molecular structure of a chemical element by breaking down and forming chemical bonds, so as to produce a new chemical compound.
The rate of a reaction is also known as reaction rate and it refers to the speed at a which the reactants in a chemical reaction are transformed into products. Some of the factors that affect the rate of a reaction are:
TemperatureCatalystConcentration of reactantsPressureIn Chemistry, an experimental method which cannot be used to measure the rate of a chemical reaction is the measurement of the equilibrium concentration of an acidic product by titrating it with a strong base because the concentration of product always remain the same.
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A compound has an M-/M-2 ratio of 75:25. Which of the following could be the molecular formula of this compound? a) CH2Br2 b) CH2Cl2 c) CHCI d) CH:Bre) CHF
Answer:
c) CH₃Cl
Explanation:
Due the relative abundance of chlorine and bromine. It is possible to determine which of the halogens is present in a mass spectrum of a organic compound:
The Cl-35, Cl-37 have a relative abundance of 75/25; Br-79 and Br-81 of 50/50.
For that reason, if a compound has a M/M+2 ratio of 75:25 you can be sure the compound has 1 Cl in its structure. Thus, the only possible structure is:
c) CH₃ClLight energy from the sun is converted by plants into
A electricity
B mechanical energy
C leaves
D chemical energy
A student in a chemistry lab is conducting an experiment using chemicals. Several violations were observed by the instructor. Which of the following methods below would best prevent a contamination of chemicals in the eyes?
Answer:
I would suggest wearing safety glasses as it minimizes the chance of harmful chemicals entering the eyes
Explanation:
An insoluble solid is placed in water and the system allowed to reach equilibrium. The ratio of the rate at which ions join the solution and the rate at which ions join the lattice will be:
Answer:
One.
Explanation:
Hello,
In this case, the equilibrium condition is characterized by the equality of the rates at which a process happen and the contrary process happen, so its ratio is 1. For instance, a chemical reaction at equilibrium will have a contant ratio of the velocity at which the products are formed and the reactants consumed
However, for the described insoluble solid that is allowed the reach equilibrium, the ratio of the rate at which ions join the solution and the rate at which ions join the lattice will be one since it reaches an equilibrium state.
Best regards.
The value of ΔG° (kJ/mol) at 25°C for the formation of phosphorous trichloride from its constituent elements: Fe2O3(s) + 3CO(g) → 2Fe(s) + 3CO2(g) A) –59.2 B) +59.2 C) –642 D) +75.6 E) –373 F) –29.4
Answer:
F. [tex]\mathsf{\Delta G^0 \simeq -29.4 \ kJ}[/tex]
Explanation:
GIven that:
The chemical equation for the reaction is:
[tex]\mathtt{Fe_2O_{3(s)} + 3CO_{(g)} \to 2Fe _{(s)} + 3CO_{2(g)}}[/tex]
The value of the ΔG° (kJ/mol) at 25 °C
[tex]\Delta G^0 = \begin {pmatrix} 2( \Delta G_f^0 \ Fe_{(s)} )+ 3 ( \Delta G_f^0 \ CO_{2(g)} ) - 1 ( \Delta G_f^0 \ Fe_2CO_3_{(s)} + 3 ( ( \Delta G_f^0 \ CO _{(g)} ) \end {pmatrix}[/tex]
where;
[tex]\Delta G_f^0 \ Fe_{(s)} = 0[/tex]
[tex]\Delta G_f^0 \ CO_{2(g)} = -394.359 \ kJ/mole[/tex]
[tex]\Delta G_f^0 \ Fe_2CO_3_{(s)} = -742.2 \ kJ/mole[/tex]
[tex]\Delta G_f^0 \ CO _{(g)}= -137.168\ kJ/mole[/tex]
Replacing the values ; we have
[tex]\Delta G^0 = \begin {pmatrix} 2(0 )+ 3 ( -394.359 ) ) -( 1 (-742.2) + 3 (-137.168 ) \end {pmatrix}[/tex]
[tex]\Delta G^0 = \begin {pmatrix} 0 -1183.077 ) -(-742.2- 411.504 \end {pmatrix}[/tex]
[tex]\Delta G^0 = \begin {pmatrix} -1183.077 +742.2+ 411.504 \end {pmatrix}[/tex]
[tex]\mathtt{\Delta G^0 = -29.373 \ kJ}[/tex]
[tex]\mathsf{\Delta G^0 \simeq -29.4 \ kJ}[/tex]
10g = __________ mg? *
Answer:
Explanation:
as we know that
1g =1000mg
so
10g=10*1000
10g=10000
A wooden block has a mass of 20 g and dimensions of 5 cm x 1 cm x 1 cm.
A. What is the volume?
B. What is the density?
(Helppp)
Answer:
V = 5 cm³
ρ = 4 g/cm³
Explanation:
Step 1: Calculate the volume (V)
We have a wooden cuboid of dimensions 5 cm × 1 cm × 1 cm. We can calculate its volume using the following expression.
V = 5 cm × 1 cm × 1 cm
V = 5 cm³
Step 2: Calculate the density (ρ)
The density is equal to the mass divided by the volume.
ρ = m / V
ρ = 20 g / 5 cm³
ρ = 4 g/cm³
The 488 nm laser is shine on a lithium metal whose work function is 2.9 eV will you be able to see any photoelectrons? if yes what is the kinetic energy of the electrons if no what wavelength of light should be used to see the photoelectrons
Answer:
There will not be any ejection of photoelectrons
Explanation:
Energy of the photon= hc/λ
Where;
h= Plank's constant
c= speed of light
λ= wavelength of the incident photon
E= 6.6×10^-34 × 3 ×10^8/488 × 10^-9
E= 4.1 ×10^-19 J
Work function of the metal (Wo)= 2.9 eV × 1.6 × 10^-19 = 4.64 × 10^-19 J
There can only be ejected photoelectrons when E>Wo but in this case, E<Wo hence there will not be any ejection of photoelectrons.
The term electron capture best fits which of the following descriptions?
A. Electron capture is a phenomenon exhibited by an unstable nucleon that spontaneously converts into a more stable nuclei.
B. Electron capture is the combination of a core electron with a proton to yield a neutron within the nucleus.
C. Electron capture is the addition of an electron to a neutral atom to form an anion.
D. None of the above.
Answer:
Option B:
Electron capture is the combination of a core electron with a proton to yield a neutron within the nucleus.
Explanation:
The electron capture is a nuclear process whereby a neutral atom absorbs an electron from its closest shell (which is usually the K shell of the atom).
This capture phenomenon, causes one of the protons within the nucleus of the atom to convert into a neutron because of the merging of the positive and negative charges. Once they merge, a light particle called the electron neutrino is emitted from the nucleus of the atom.
This phenomenon occurs mostly in atoms that have a proton-rich nucleus. This provides the positive charge that pulls the electron from its shell into the nucleus of the atom.
How many atom are in 5fes2, 6c2h4o2 and 2cah2po42
Answer:
83 atoms
Explanation:
5*(1 fe + 2 S) + 6(2 C + 4H + 2O) + 2*2(1 Ca + 2 H + 1 P + 4 O) = 15 + 36 + 32 = 83 atoms
A match is lit and held under a cold piece of metal. The following observation are made.A) the match burnsB) the metal gets warmerC) water condenses on the metalD) soot (carbon) is deposited on the metal.Which of these occurrences are due to physical changes and which are due chemical changes?
Answer:
A - chemical changes
B - Physical changes
C - Chemical changes
D - Chemical changes
Explanation:
First and foremost, a chemical change is an irreversible change in the chemical properties of a substance leading to the formation of a new substance or substances while a physical change is a reversible change to the properties of a substance.
The burning of a match stick is an irreversible process involving the reaction of the various component of the match head (potassium chlorate, sulfur, glass powder) with that of the side of the box holding the match (phosphorus, binder, glass powder). Hence, it is considered a chemical reaction.
Warming of the metal is a reversible process and hence, a physical reaction. Warming involves a rise in temperature due to the heating. Once the heat source is removed and the metal allowed to stay for a while, its temperature will return back to the original temperature.
Water condensation and deposition of soot on the metal can be considered a chemical reaction. A reaction that leads to the formation of, at least, one new product is definitely a chemical reaction.
If 12.8 g lead(II) sulfate (303.3 g/mol) precipitates when excess potassium chloride is added to 1.65 L of a water sample, what is molar concentration of Pb2+ in the sample?
Answer:
[tex]M=0.0256M[/tex]
Explanation:
Hello,
In this case, the undergoing chemical reaction is:
[tex]PbSO_4(aq)+2KCl(aq)\rightarrow PbCl_2(s)+K_2SO_4(aq)[/tex]
In such a way, since all the lead (II) is converted due to the excess of potassium chloride, the moles of lead (II) in the sample are computed from the mass of lead (II) sulfate:
[tex]n_{Pb^{2+}}=12.8gPbSO_4*\frac{1molPbSO_4}{303.3gPbSO_4} *\frac{1molPb^{2+}}{1molPbSO_4} \\\\n_{Pb^{2+}}=0.0422molPb^{2+}[/tex]
Thus, since volume of the solution is 1.65 due to the fact that the addition of the reactants is not enough to significantly modify the reaction's volume, the resulting molar concentration of the lead (II) ions is:
[tex]M=\frac{n_{Pb^{2+}}}{V}=\frac{0.0422molPb^{2+}}{1.65L}\\ \\M=0.0256M[/tex]
Regards.
The carbon atoms in saturated hydrocarbons ________. Group of answer choices contain a benzene ring contain at least one double bond contain both a double and a triple bond have only single bonds contain at least one double bond
Answer:
Have only single bonds.
Explanation:
Hello,
In this case, we need to remember that saturation is a state at which a carbon chain contains no insaturations, that is neither double nor triple bonds such case are alkenes and alkynes, but saturations only which are characterized by the presence of single bonds between adjacent carbon atoms. Such is the case of ethane (CH₃-CH₃), propane (CH₃-CH₂-CH₃), butane (CH₃-CH₂-CH₂-CH₃) and so on.
Best regards.
In general, which of the following gases would you expect to behave the most ideally even under extreme conditions? View Available Hint(s) In general, which of the following gases would you expect to behave the most ideally even under extreme conditions? N2 CO H2
Answer:
The correct option is H₂
Explanation:
An ideal gas is the gas that obeys the gas laws perfectly. There molecules occupy little/negligible space with no interaction. Since they occupy negligible space, it can be said that the smaller the molecule of a gas, the more it behaves like an ideal gas. There size also accounts for there weak intermolecular force between it's molecules.
From the explanation above, H₂ has the smallest molecule and hence will behave the most like an ideal gas.
The gases that one would expect to behave the most ideally even under extreme conditions is H2.
An ideal gas is commonly described to as gases that are present i gas molecules that do not encounter any kind of interaction with the neighboring molecules.H2 is simply known as a molecule of hydrogen that has two hydrogen atoms which are bonded to each other by covalent bond.
Due to the fact that the hydrogen atom has a smaller size and lesser electronegativity the hydrogen molecule is thus regarded to be the least polar.
N2 is known to have greater polarizability than hydrogen molecule and thus cannot be the answer.
Note that for a gas to behave ideally, the attractive and repulsive intermolecular forces need to be negligible. When looking at the three molecules
H2,N2,CO, the molecule which is most polar will behave least ideally.
Therefore, hydrogen molecule will have the least intermolecular forces and will be most ideal.
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Radioactive manganese-52 decays with a half-life of 5.6 days. A chemist obtains a fresh sample of manganese-52 and measures its radioactivity. She then determines that to do an experiment, the radioactivity cannot fall below 25% of the initial measured value. How long does she have to perform the experiment?
Answer: 11.2 days
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{5.6days}=0.124days^{-1}[/tex]
b) for completion of 75% of reaction
[tex]t=\frac{2.303}{0.124}\log\frac{100}{100-75}[/tex]
[tex]t=\frac{2.303}{0.124}\log\frac{100}{25}[/tex]
[tex]t=11.2days[/tex]
The time for which she has to perform the experiment is 11.2 days
Sam wished to investigate how fertilizer run-off affects the growth of algae in freshwater lakes and streams. He set his experiment up in this way. He placed
900 ml of water into each of five 1000 ml glass beakers. To each beaker he added 5 ml of water from an aquarium which contained a large concentration of
algae. The beakers were placed under a grow light which was timed to provide 12 hours of light each day. Liquid fertilizer was added to the beakers in the
following amounts: Beaker A-8 mi fertilizer, Beaker B - 6 ml fertilizer, Beaker C - 4 ml fertilizer, Beaker D-2 mi fertilizer, and Beaker E - no fertilizer. Each
week a random sample from each of the beakers was examined under a microscope to get a count of the number of algal cells present.
What is the independent variable in this experiment?
O hours of daylight
O amount of water
O amount of fertilizer
O number of algal cells
Answer:
amount of fertaliser--> the independant variable is the one being changed
Do all living things have cells?
Answer:
Yes
Explanation:
All living things do have cells
Answer:
yes they all have to have cells for every living thing
Explanation:
if their was no cells in existence all the living will soon to be dead.
What is the mass of 10.0 cm the 3rd power of water
If you mean cubic cm, then it will be about 10 grams
limitations of bohr
Answer:
Bohr's Atomic model
Explanation:
The limitations of Bohr’s model are Bohr’s model of an atom that could not explain the line spectra of atoms containing more than one electron called multi-electron atoms.
What do viceroy butterflies use to look like poisonous Monarch butterflies?
They use something called Mullerian mimic so they will be protected from predators
Explanation:
3. A balloon is filled with a mystery fluid that has a mass of 1000 kg and a volume of
of |
500 mL.
A. What is the density of the fluid?
B. Will the balloon sink or float in water?
(Helpppp ppls)
If 28.0% of a sample of gallium-66 decays in 4.46 hours, what is the half-life of this isotope (in hours)?
Answer:
I hope it will work dear,
Explanation:
by simple mathematical rule,
if 28%=4.46 hrthen we know at half life 50% decay occur hence we get
2. 50% = T 1/2
solving the 2 equations by cross multiplication we will get,
T 1/2= 7.96 hr
THANKS FOR ASKING QUESTION:
Identify the major factor affecting reaction rates that accounts for the following observations:
a. Tadpoles grow more rapidly near the cooling water discharged from a power plant. 尤mpeca
b. Enzymes facilitate certain biochemical reactions but are not onsumed
c. Hydrogen peroxide antiseptic rapidly decomposes when applied to an open wound.
Answer:
a. Tadpoles possess the tendency to grow more rapidly close to the cooling water released from the power plant as the temperature is greater in these waters, permitting them to acquire more nutrients. Thus, in the given case, the factor is the temperature of the system.
b. In the given case, the factor is the catalyst, and in the given case enzymes are the biological catalyst. An enzyme increases the rate of the reaction as they lower the activation energy.
c. In the given case, the factor is the enzyme, as the blood comprises an enzyme, peroxidase, which catalyzes the decomposition of hydrogen peroxide.
The MSDS for benzene indicates that it is a clear liquid that has a substantial vapor pressure. It has a health rating of 2, a fire rating of 3, and a reactivity rating of 0. It is a cancer-causing agent. Based on this information, which statement about benzene is accurate?
Answer:
Benzene must be kept away from flames.
Explanation:
Edguenuity 2020
The most accurate statement about Benzene is : Keep Benzene away from flames.
Although your question is incomplete a general answer is provided based on the MSDS provided in the question
Benzene is a colorless gas that exhibits a high level of flammability, it also has a sweet odor just like gasoline, it is a cancer-causing agent when humans are exposed to it for too long. based on its flammability it is advisable to keep flammable materials and flammable sources ( flames ) away from Benzene. and to also reduce the rate of human exposure to benzene as well.
Therefore we can conclude that based on the MSDS provided in the question the most accurate statement about benzene is Benzene should be kept away from flames.
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On the basis of intermolecular forces of attraction, rank the following three compounds in terms of increasing boiling point.
CH3CH2OH
CH3OCH3
CH3CH2CH3
a. (lowest bp) CH3CH2CH3 < CH3OCH3 < CH3CH2OH (highest bp)
b. (lowest bp) CH3CH2OH < CH3OCH3 < CH3CH2CH3 (highest bp)
c. (lowest bp) CH3OCH3 < CH3CH2OH < CH3CH2CH3 (highest bp)
d. (lowest bp) CH3CH2OH < CH3CH2CH3 < CH3OCH3 (highest bp)
e. (lowest bp) CH3CH2CH3 < CH3CH2OH < CH3OCH3 (highest bp)
Answer:
a. (lowest bp) CH3CH2CH3 < CH3OCH3 < CH3CH2OH (highest bp
Explanation:
CH3CH2OH is an alkanol. The intermolecular forces present within the molecules include dispersion forces, dipole-dipole attraction as well as hydrogen bonding which is the major intermolecular force of attraction present.
CH3OCH3 is an ether. The intermolecular forces present within the molecules are dispersion forces and dipole-dipole attraction.
CH3CH2CH3 is an alkane. The only intermolecular forces present is dispersion forces.
The order of increasing strength of these intermolecular forces is dispersion forces ,dipole-dipole forces<hydrogen bonding, the alkanol has the highest bioling point, followed by the ether and then the alkane with the lowest boiling point.
The ranking of the compounds in terms of increasing the boiling point is option a.
What is ethanol?Ethanol i.e. (CH3-CH2-O-H) has three types of intermolecular interactions i.e. weak van der Waals interaction, dipole-dipole interaction, and strong intermolecular H-bonding interaction.
While on the other hand, in dimethyl ether (CH3-O-CH3) have two types of interactions - weak van der Waals interaction, and dipole-dipole interaction.
In propane (CH3-CH2-CH3) has only weak van der Waals interaction.
So ethanol needed more energy to overcome this these interactions for the conversion to a liquid state to the gaseous state.
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Calculate the pH of a buffer solution that contains 0.25 M benzoic acid (C 6H 5CO 2H) and 0.15M sodium benzoate (C
Answer:
[tex]pH=3.97[/tex]
Explanation:
Hello,
In this case, for the calculation of the pH of the given buffer we need to use the Henderson-Hasselbach equation:
[tex]pH=pKa+log(\frac{[base]}{[acid]} )[/tex]
Whereas the pKa for benzoic acid is 4.19, the concentration of the base is 0.15 M (sodium benzoate) and the concentration of the acid is 0.25 M (benzoic acid), therefore, the pH turns out:
[tex]pH=4.19+log(\frac{0.15M}{0.25M} )\\\\pH=3.97[/tex]
Regards.