Answer:
B. Activation Energy
Explanation: A P E X
Answer: the answer is activation energy
Explanation:
i just took the test
BaO2 is a peroxide. Why?
Answer:
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1. How many Chromium atoms are found in 25.8 milligrams of Chromium?
Answer: 51.9961 g/mol, don't know if it helps :)
Explanation:
Answer:
Chromium is a steel-gray, lustrous, hard metal that takes a high polish, is fusible with difficulty, and is resistant to corrosion and tarnishing.
The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +4 and +5 are relatively rare. Chromium compounds of oxidation state 6 are powerful oxidants.ion:
Oxygen gas is made of molecules like the one this model shows. Which
chemical formula most likely describes oxygen gas?
A. OG
B. 00
C. 02
D. 0100
Calculate the number of S atoms in 0.670 mole of S.
Answer:
4.03 × 10²³ atomsExplanation:
The number of S atoms can be found by using the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
N = 0.67 × 6.02 × 10²³
We have the final answer as
4.03 × 10²³ atomsHope this helps you
plz help me... my ppr is gonig on......
In first line of Lyman Series, wave number is
1 point
82.26 x 10^5
97.49 x 10^5
109.678 x 10^5
none
Answer:
geruow0irghvn3p0unhie0ghik
Explanation:
10. INFER: Why can the reactant in a
decomposition reaction never be an element?
Answer:
Because elements cannot decompose
Explanation:
Elements are distinct substances that cannot be split-up into simpler substances. Such substances are only made up of one atom.
An atom is the smallest indivisible particle of substance that can take part in chemical reaction. By chemical means, an atom cannot be broken down. Therefore, an element cannot break down during decomposition reaction. A decomposition reaction is one in which a substance breaks down into two or more products.Explain why atoms in group 2a are likely to form ions with plus two charge explain why why atoms in group 7a are likely to form ions with a minus one charge
Answer:
Atoms in group 2a are likely to form ions with a +2 charge because they have two valence electrons, both of which experience a very weak pull from the nucleus due to electron shielding. This causes the atoms to be easily pulled away from the nucleus, creating the +2 ions we see in nature.
Atoms in group 7a are likely to form ions with a -1 charge because they are one electron away from completing their outermost shell. The large number of protons in the middle of these atoms also causes the valence electrons to experience a stronger net force. This force also pulls strongly on the valence electrons of other atoms, causing the -1 ions we see in nature.
A 2kg metal cylinder is supplied with 1600J of energy to heat it from 5*C to 13*C. What is the SHC of the metal?
Answer:
100Jkg/°C
Explanation:
Given parameters:
Mass of metal = 2kg
Amount of heat energy = 1600J
Initial temperature = 5°C
Final temperature = 13°C
Unknown:
Specific heat capacity of the metal = ?
Solution:
Specific heat capacity of a body is the amount of heat needed to raise the temperature of unit mass of a body by 1°C.
H = m x C x (T₂ - T₁ )
H is the amount of heat
m is the mass
C is the unknown specific heat capacity
T is the temperature
Insert the parameters and solve;
1600 = 2 x C x (13 - 5)
1600 = 16C
C = 100Jkg/°C
The equation 2NaNO3 + CaCl2 - 2NaCl + Ca(NO3)2 is balanced. How many atoms of sodium (Na) are there on either side of the equation? one two four six
Question: How many atoms of sodium (Na) are there on either side of the equation?
Options: A) one B) two C) four D) six
Correct answer: D) six
Answer:
It is NOT six, i took the test and got it wrong. The CORRECT answer is 2
Explanation:
1. A baseball pitcher won 75% of the games he pitched. If he pitched 43 ballgames, how many games
did he win?
Answer:
He won 32 games.
Explanation:
Another way of expressing 75% is 75/100.
To calculate how many games the baseball pitcher won, we multiply the total of games played (43, in this case) by the percent won:
43 * 75/100 = 32.25 ≅ 32
So the baseball pitcher won 32 games.
Scientists who are investigating what has happened over the years to the people who were exposed to radiation during the 1986 Chernobyl nuclear disaster are conducting what type of study
Answer:
Observational study
Explanation:
An investigation of what happened over the years to the people who were exposed to radiation during the 1986 Chernobyl nuclear disaster would be termed an observational study because it will require observing subjects and finding out if there is a kind of correlating factor in the subjects that could indicate the level of exposure to the nuclear radiation.
There are basically two types of research studies:
1. Observational studies
2. Experimental studies
Observational studies involve just the observation of subjects and trying to find out some correlation factors. This kind of study could be prospective when it deals with what could happen in the future based on certain factors or retrospective when it considers what has already happened. An observational study can be cross-sectional, case-only, case-control, or cohort study.
Experimental studies are also referred to as randomized or controlled trial studies. Here, subjects are grouped and each group receives a different treatment in order to isolate the effect of a particular factor or variable relating to the treatment.
Which of the following grouping contains only representative elements?
A. Na, Co, S
B. Ni, Ga, Zn
c. AI, Mg, LÍ
D. CI, O, Cd
Answer:
C
Explanation:
Al=Aluminum
Mg=Magnesium
Exactly 56 grams of iron is mixed with 156 grams of oxygen. The elements are heated and they react. What best describes which remains after the reaction is complete?
Answer:
Explanation:
The chemical expression for the reaction between iron and oxygen is:
4Fe(s) + 3O₂ (g) [tex]\to[/tex] 2Fe₂O₃ (s)
The number of moles of Fe = mass of Fe/ molecular mass of Fe
The number of moles of Fe = 56 g/ 55.845 g/mol
The number of moles of Fe = 1.002 moles of Fe
The number of moles of oxygen = mass of oxygen/ molecular mass of oxygen
The number of moles of oxygen = 156 g /32 g/mol
The number of moles of oxygen = 4.875 moles of oxygen
Assume that Fe is the limiting reactant, the number of Fe₂O₃ can be calculated as:
moles of Fe₂O₃ = 1.002 mole of Fe × 2 moles of Fe₂O₃/ 4 moles of Fe
moles of Fe₂O₃ = 0.501 mole of Fe₂O₃
Assume that O₂ is the limiting factor, the number of Fe₂O₃ is:
moles of Fe₂O₃ = 4.875 moles of O₂ × 2 moles of Fe₂O₃/ 3 moles of O₂
moles of Fe₂O₃ = 3.25 mole of Fe₂O₃
Thus, after the reaction is complete, Fe and O₂ contain different moles of Fe₂O₃. Only Fe gets consumed in the reaction and it is the limiting factor.
2. Molecular solutions do not conduct electricity because they contain: *
(1 Point)
The ions are able to move freely from one place to another. So that they conduct electricity. But the molecular solutions does not electricity.
What is a molecular solution?The molecular solution is composed of molecules and consists of non - metallic atoms. These atoms are held together by the covalent bonds. The flow of charged particles is responsible for the conduction of electricity. If there is no flow of electrons or ions then there will be no electricity.
In the molecular solutions, the molecules present are not dissociated into respective ions. Since the molecules are not converted into the charged particles no electricity is produced.
A molecular solution is regarded as a non-electrolyte which does not contain ions. But electrolytes are dissociated into ions and thereby conducts electricity. So all electrolytes are good conductors of electricity.
Thus molecular solution does not contain ions.
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Which of the following is best for measuring 10.0 ml water
A- conical flask
B- beaker
C- pipett
Answer:
B- beaker
Explanation:
..............
Please help me it due today at 11:00am please help me will mark the brainiest please
Calculate ΔHrxn for the following reaction:CH4(g)+4Cl2(g)→CCl4(g)+4HCl(g)Use the following reactions and given ΔH′s.C(s)+2H2(g)→CH4(g)ΔH=−74.6kJC(s)+2Cl2(g)→CCl4(g)ΔH=−95.7kJH2(g)+Cl2(g)→2HCl(g)ΔH=−184.6kJ
Answer:
ΔH= -390.3kJ
Explanation:
Using Hess's law, we can obtain ΔHrxn from the sum of related reactions.
Using:
(1) C(s) + 2H2(g) → CH4(g) ΔH=−74.6kJ
(2) C(s) + 2Cl2(g) → CCl4(g) ΔH=−95.7kJ
(3) H2(g) + Cl2(g) → 2HCl(g) ΔH=−184.6kJ
(2) - (1):
CH4(g) + C(s) + 2Cl2(g) → CCl4(g) + C(s) + 2H2(g)
CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g)
ΔH= -95.7kJ - (-74.6kJ) = -21.1kJ
This reaction + 2*(3):
2H2(g) + 2Cl2(g) + CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g) +4HCl(g)
CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
ΔH= -21.1kJ + 2*-184.6kJ
ΔH= -390.3kJThe pressure of a compressed gas is 1.45 atm. What is this pressure in kPa
Answer:
1.45 Atmospheres = 146.92125 Kilopascals, or about 146.9 Kilopascals
Explanation:
1 Atmosphere = 101.325 Kilopascals, so 101.325 Kilopascals x 1.45 Atmospheres = 146.92125 Kilopascals.
Using the conversion table, the pressure of the compressed gas at 1.45 atm when converted to kilopascal becomes 146.92 kPa.
How to convert from atm to kPa?
Atm is the standard atmosphere which is a unit of pressure.
From conversion table
1 atm atmospheric pressure is equivalent to 101.325 kPa ( kilopascal ).
Now, the pressure of the compressed gas at 1.45 atm will be;
P = 1.45 × 101.325 kPa
P = 146.92 kPa
Therefore, the pressure of the compressed gas at 1.45 atm when converted to kilopascal using the conversion table becomes 146.92 kPa.
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which have
different numbers of electrons?
Answer:
These are called isotopes. They have the same number of protons (and electrons), but different numbers of neutrons. Different isotopes of the same element have different masses. Mass is the word for how much substance (or matter) something has.
Calculate the mass percent composition of iron for the third one of these iron ores.
Iron is mined from the earth as iron ore. Common ores include Fe2O3 (hematite), Fe3O4 (magnetite), and FeCO3 (siderite).
Answer:
[tex]\% Fe=48.2\%[/tex]
Explanation:
Hello!
In this case, since the percent composition of an element in a compound is given by:
[tex]\% i =\frac{z_i*m_i}{MM}*100\%[/tex]
Whereas i represent the element in the compound for which we want compute the mass percent. As required for siderite, FeCO3 whose molar mass is 115.854 g/mol, and knowing there is one iron atom there with an atomic mass od 55.85 g/mol, the mass percent of iron there is:
[tex]\% Fe=\frac{1*55.85}{115.854}*100\%\\\\\% Fe=48.2\%[/tex]
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A container holds 3.41×10−3mol of carbon dioxide (CO2). After the addition of 8.41×10−4mol of carbon dioxide, the volume of the container increases to 95.2mL, with the temperature and pressure remaining constant. What was the initial volume of the container?
Answer:
76.366
Explanation:
Knewton answer is 76.4
Answer:
76.4mL
Explanation:
First, calculate the final number of moles of carbon dioxide (n2) in the container.
n2 = n1+n added = 3.41×(10^-3) mol+8.41×(10^-4) mol = 4.25×(10^-3) mol
Rearrange Avogadro's law to solve for V1.
V1 =(V2×n1)/n2
Substitute in the known values for n1, V2, and n2.
V1 = (95.2mL×(3.41×10^-3 mol))/(4.25×(10^-3) mol)=76.4mL
So the initial volume is 76.4mL.
who established the two important laws of chemical combination combination state them
Answer:
Antoine Lavoisier
1) Law of Conservation of Mass
French chemist, Antoine Lavoisier in 1789, studied this law. This law states that “In all physical and chemical changes, the total mass of the reactants is equal to that of the products” or “Mass can neither be created nor destroyed.”
A graduated cylinder initially has 32.5 mL of water in it. After a 75.0 g piece of lead (Pb) is added to the graduated cylinder, the water level rises to the 39.1 mL mark. What is the the volume of the piece of lead.
Answer:
39.1-32.5 and you will find your answer it always like that, you subtract your starting point from your ending point
Explanation:
The volume of the piece of lead is 6.6 mL
From the question given above, the following data were obtained:
Volume of water = 32.5 mLMass of lead (Pb) = 75 gVolume of water + Lead = 39.1 mLVolume of lead =?The volume of the lead can be obtained as follow:
Volume of lead = (Volume of water + Lead) – (Volume of water)
Volume of lead = 39.1 – 32.5
Volume of lead = 6.6 mL
Therefore the volume of the lead is 6.6 mL
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A mixture of neon and xenon gases, at a total pressure of 739 mm Hg, contains 0.919 grams of neon and 19.1 grams of xenon. What is the partial pressure of each gas in the mixture?_______g Xe
Answer:
Partial pressure of neon = 175 mmHg
Partial pressure of xenon = 564 mmHg
Explanation:
The partial pressure of a gas in a mixture can be calculated as the product of the mole fraction of the gas (Xi) and the total pressure (Pt), as follows:
Pi = Xi Pt
The total pressure is 739 mmHg ⇒ Pt = 739 mmHg
In order to calculate the mole fraction of each gas, we have to first calculate the number of moles of each gas (n) by dividing the mass of the gas into the molar mass (MM):
For neon gas (Ne):
MM(Ne) = 20.18 g/mol
n(Ne)= mass/MM = 0.919 g x 1 mol/20.18 g = 0.045 mol Ne
For xenon gas (Xe):
MM(Xe) = 131.3 g/mol
n(Xe)= mass/MM = 19.1 g x 1 mol/131.3 g = 0.145 mol Xe
Now, we calculate the mole fraction (X) by dividing the number of moles of the gas into the total number of moles (nt):
nt= moles Ne + moles Xe = 0.045 mol + 0.145 mol = 0.190 mol
X(Ne) = moles Ne/nt = 0.045 mol/0.190 mol = 0.237
X(Xe) = moles Xe/nt = 0.145/0.190 mol = 0.763
Finally, we calculate the partial pressures of Ne and Xe as follows:
P(Ne) = X(Ne) x Pt = 0.237 x 739 mmHg = 175 mmHg
P(Xe) = X(Xe) x Pt = 0.763 x 739 mmHg = 564 mmHg
A 13.8 g of zinc is heated to 98.8 c in boiling water and then dropped onto a beaker containing 45.0 g of water at 25.o °C .when the water and metal come to thermal equilibrium the temperature is 27.1°C .what is the specific heat capacity
Answer:
[tex]C_{zinc}=0.400\frac{J}{g\°C}[/tex]
Explanation:
Hello!
In this case, by considering thermodynamics and the temperature of zinc, we can infer it is hot while water is cold, it means that the heat lost by the zinc is gained by the water and we can write:
[tex]Q_{Zn}=-Q_{water}[/tex]
In terms of mass, specific heat and temperatures we can write:
[tex]m_{Zn}C_{Zn}(T_{eq}-T_{Zn})=-m_{water}C_{water}(T_{eq}-T_{water})[/tex]
In such a way, by solving for the specific heat capacity of the zinc we write:
[tex]C_{zinc}=\frac{-m_{water}C_{water}(T_{eq}-T_{water})}{m_{Zn}(T_{eq}-T_{Zn})}[/tex]
Thus, by plugging in the given values we obtain:
[tex]C_{zinc}=\frac{-45.0g*4.184\frac{J}{g\°C}* (27.1\°C-98.8\°C)}{13.8g*(27.1\°C-98.8\°C)}\\\\C_{zinc}=0.400\frac{J}{g\°C}[/tex]
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How many moles of NaCl , if mixed with excess Pb2+ ions in solution, would be needed to form 45.5 g of PbCl2 ?
The number of mole of NaCl needed to react with excess Pb²⁺ to produce 45.5 g of PbCl₂ is 0.328 mole
We'll begin by calculating the number of mole in 45.5 g of PbCl₂. This can be obtained as follow:
Mass of PbCl₂ = 45.5 g
Molar mass of PbCl₂ = 207 + (35.5×2) = 278 g/mol
Mole of PbCl₂ =?Mole = mass / molar mass
Mole of PbCl₂ = 45.5 / 278
Mole of PbCl₂ = 0.164 mole Finally, we shall determine the number of mole of NaCl needed to produce 0.164 mole (i.e 45.5 g) of PbCl₂. This can be obtained as follow:2NaCl + Pb²⁺ —> PbCl₂ + 2Na⁺
From the balanced equation above,
2 moles of NaCl reacted to produce 1 mole of PbCl₂
Therefore,
Xmol of NaCl will react to produce 0.164 mole of PbCl₂ i.e
Xmol of NaCl = 2 × 0.164
Xmol of NaCl = 0.328 mole
Thus, the number of mole of NaCl needed for the reaction is 0.328 mole
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What are things animals might do to survive?
Answer:
Animals need food, water, shelter, and space to survive. Herbivores can live only where plant food is available. Carnivores can live only where they can catch their food. Omnivores can live in many places because they eat both plants and animals.
Suppose the current flowing from a battery is used to electroplate an object with silver. Calculate the mass of silver that would be deposited by a battery that delivers 1.65 A·hr of charge.
Answer:
m = 0.00659 kg = 6.59 g
Explanation:
From Faraday's Law of Electrolysis, we know that:
m = ZQ
where,
m = mass of silver deposited = ?
Q = charge supplied = (1.65 A-hr)(3600 s/1 hr) = 5940 C
Z = electrochemical equivalent of silver = 1.18 x 10⁻⁶ kg/C
Therefore,
m = (1.11 x 10⁻⁶ kg/C)(5940 C)
m = 0.00659 kg = 6.59 g
The mass of silver that would be deposited by a battery is 6.65 grams
The precipitation of Ag requires the removal of one electron. The reduction process for silver electrode at the cathode is as follows:
[tex]\mathbf{Ag^+ + e^- \to Ag(s)}[/tex]
The current flowing in the battery = 1.65 A = 1.65 C/sThe time at which the current is flowing = 1 hr = 3600sec∴
The charge Q = Current (I) × time (t)Charge Q = 1.65 C/s × 3600 sCharge (Q) = 5940 CIn one mole of an electron, the charge carried = 96500 C
Recall that:
The atomic mass of silver (Ag) = 108 g
∴
The mass of silver that would be deposited in a 5940 C can be computed as:
[tex]\mathbf{=5940\ C \times \dfrac{108 \ g }{96500 \ C}}[/tex]
= 6.65 grams
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Sweat is made up of all EXCEPT what?
*
A.Sugar
B.Salt
C.Urea
D.Urine
What are five minerals found on space rocks
Answer:
oxygen, silicon, iron, calcium, sodium
Explanation:
these are all found in space rocks known as meteorites. hope this helps :)