An atom of an element contains 20 protons, 20 neutrons, and 20 electrons. This element is in Group *
Answer:
it is calcium. it is in group(llA).
Answer:
calcium it lies in group(IIA)hope it is helpful to you
The energy of a pendulum is recorded at different positions in the table below. Use the data in the table to determine the amount of kinetic energy the pendulum had at Position 2. Record your answer below.
Please help me I just want to get this test over with
Answer:
so i got 34.5
Explanation:
How many moles are in a balloon that is 50.2L, 755 mmHg and -22.0C?
Answer:
n ≈ 2.42 moles
General Formulas and Concepts:
Chem
Ideal Gas Law: PV = nRT
P is pressure in mmHgV is volume in litersn is number of molesR is a constant (62.4 L · mmHg/mol · k)T is temperature in KelvinsK = °C + 273
Explanation:
Step 1: Define
V = 50.2 L
P = 755 mmHg
T = -22.0°C = 251 K
Step 2: Find moles n
(755 mmHg)(50.2 L) = n(62.4 L · mmHg/mol · k)(251 K)
37901 mmHg · L = n(15662.4 L · mmHg/mol)
n = 2.41987 moles
Step 3: Check
We are given 3 sig figs. Follow sig fig rules.
2.41987 moles ≈ 2.42 moles
what is the mass of silver that has a volume of 238mL? the density of silver is 10.5 g/cm^2
Explanation:
What volume of silver metal will weigh exactly 2500.0 g. The density of silver is 10.5 g/cm3. cm3 = 2500.0 g / 10.5 g/cm3 = 238 cm3
What is the density of a piece of wood that has a mass of 25.0 grams and a volume of 29.4 cm3? d = .85 g/cm3
How does one determine a percent composition from an empirical
formula?
A. Divide the atomic mass of the element by its subscript and
multiply by 100%
O B. Divide the mass of the compound by the atomic mass of
the element and multiply by 100%
O C. Divide the subscript of the element by the mass of the
element and multiply by 100%
O D. Divide the total mass of each element by the mass of the
compound and multiply by 100%
The way one determines a percent composition from an empirical formula is to divide the total mass of each element by the mass of the compound and multiply by 100%.
What is empirical formula?Empirical formula is a notation that indicates the ratios of the various elements present in a compound, without regard to the actual numbers.
The empirical formula of a compound is the simplest ratio that can exist between the constituent elements of a compound.
However, the percent composition of a compound can be determined by dividing the total mass of each element by the mass of the compound and multiply by 100%.
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For a particular reaction, the change in enthalpy is â9kJmole and the activation energy is 13kJmole. The enthalpy change (ÎH) and activation energy (Ea) for the catalyzed reaction could be which of the following? a. â9kJmole,5kJmole. b. â9kJmole,19kJmole.c. â14kJmole,5kJmole.d. â14kJmole,â13kJmole.
Answer:
The answer is Option a, that is "−9kJmole,5kJmole".
Explanation:
Please find the complete question in the attached file.
In the question, it uses the catalyst inside a process, which does not modify the process eigenvalues, however, it decreases the active energy with an enthalpy of -9kJmole, and also the power for activating decreases around 13 to 5 kJ mole, that's why the choice a is correct.
For the reaction of nitric oxide and oxygen to form nitrogen dioxide, the reaction begins with 12.0 g of nitric oxide and 12.0 g of oxygen at 25oC in a 10.0 L container. At equilibrium, the pressure in the container is 1148 mmHg, what is Kp?
Answer:
Explanation:
Hello!
In this case, since the undergoing chemical reaction is:
[tex]2NO+O_2\rightleftharpoons 2NO_2[/tex]
The equilibrium expression in terms of pressures is:
[tex]Kp=\frac{p_{NO_2}^2}{p_{NO}^2p_{O_2}}[/tex]
Thus, for the initial conditions, we compute the initial pressures of both nitric oxide and oxygen:
[tex]p_{NO}^{0}=\frac{12.0g*0.082\frac{atm*L}{mol*K}*298.15K}{30g/mol*10.0L}=0.978atm\\\\ p_{O_2}^{0}=\frac{12.0g*0.082\frac{atm*L}{mol*K}*298.15K}{32g/mol*10.0L}=0.917atm[/tex]
Next, since the equilibrium pressure is 1148 mmHg or 1.51 atm, we can write:
[tex]p_T=p_{NO_2}+p_{NO}+p_{O_2}\\\\1.51=2x+0.978-2x+0.917-x\\\\1.51=1.90-x\\\\x=0.39atm[/tex]
Thus, the Kp turns out:
[tex]Kp=\frac{(2*0.39)^2}{(0.978-2*0.39)^2(0.917-x)} \\\\Kp=29.4[/tex]
Best regards!
A gram of gasoline produces 45 kJ of energy when burned. Gasoline has a density of 0.77 g/mL. How would you calculate the amount of energy produced by burning 48 L of gasoline?
The energy produced in the burning of gasoline = 45 kJ/g. So, amount of energy produced by burning 48 L gasoline = 45 kJ/g×36960 g = 1663200 kJ.
what is molecular weight of ash?
Answer:
AsH(2.) CHEBI:33104
Explanation:
Molecular Weight is : 75.9296 g/mol
Las Vegas, Nevada is in a desert. How does its rapid population growth affect the
water supply? Name at least two specific ways that human activities affect the quality
of groundwater
Answer:
Many areas of the United States experience explosive population growth. The more people that reside someplace, the more demand there is for water there. Often these urban-growth expansions are unplanned and place extraordinary stress on the water supply system, mainly on the groundwater. The stress often depletes groundwater supply, thereby causing wells to dry up. Then water must be brought from somewhere else to support the local population.
Such situations have occurred all over the United States. For example, increased population growth in the southwestern United States has significantly lowered the water table 50 to 200 feet (depending on the area) since the 1940s. Managing urban growth, efforts to reduce water demand, conservation of the resource, and attempts to increase the water supply all address the problem of exceeding water resource limits.
Human activities affect groundwater quality.
Here are some sources and possible solutions to groundwater pollution:
Agriculture—Reduce usage of pesticides and fertilizers.
Landfills—Monitor for leakage and repair linings.
Underground storage tanks—Remove damaged and unused tanks.
Household wastes—Properly dispose of household hazardous waste.
Septic tank leaks—Properly maintain and repair tanks.
Explanation:
This came from the K12 learning course read this and the answer will be there. I underlined the important parts for the answer.
A 1.038 g sample of unknown containing C, H, and O yielded 2.48 g of CO2 and 0.510 g of H2O during combustion analysis. Determine the empirical formula of the compound.
A) C3H3O
B) C6H6O
C) CH3O
D) C6H6O2
E) C2H6O2
Answer:
A. C3H3O
Explanation:
We have the following data:
m = mass of organic compound = 1.038g
Then mass of CO2 is 2.48g
Also mass of H2O is 0.510g
To calculate percentage of carbon = 12 x mass of CO2 x 100/44 x mass of organic compound
This gives us 65.1 percent
Formula to calculate percentage of H=
2 x mass of water x 100/18 x mass of organic compound.
= 2 x 0.510 x 100/18x 10038
This gives 5.4%
Percentage of Oxygen =100-(percentageof carbon +percentageof H)
= 100-(65.1+5.4)
= 100-70.5
= 29.5
We have to calculate emperical formula:
For C = 65.1
65.1/12
= 5.4
= 5.4/1.8
=3
For H=5.4
5.4/1
= 5.4
= 5.4/1.8
=3
For O = 29.5
= 29.5/16
= 1.8
= 1.8/1.8
=1
So the emperical formula of organic compound is given as
C3H3O1
= C3H3O
(The atomic weights of C, H, O are 12,1,16)
1. What is the molar mass of Al?
Answer:
26.981539 u
Explanation:
A 32.65 g metal is placed in a flask. Liquid toluene is added to the flask so that the total volume of the metal and liquid toluene together is 50.00 mL. The metal and toluene together weigh 58.58 g. The density of toluene at the temperature of the experiment is 0.8640 g/mL. What is the density of the metal?
A strong electrolyte is one that ________ completely in solution. a) reacts.b) decomposes.c) disappears.d) ionizes.
Answer:
A.
Explanation:
elctrolytes decomposes
Answer:
D. ionizes
Explanation:
what step of the scientific method do we decide whether our hypothesis was correct or not
What effect does a high carbon level have on the deep ocean? Why might it be important to keep an eye on the deep ocean carbon levels? What could that one number tell you about the cycle as a whole?
High concentrations of carbon dioxide make it harder for marine animals to respire (to extract oxygen from seawater). This, in turn, makes it harder for these animals to find food, avoid predators, and reproduce. Low concentrations of oxygen can have similar effect
Becay the Ocean's Carbon Balance. The idea seemed simple enough: the more carbon dioxide that people pumped into the atmosphere by burning fossil fuels, the more the oceans would absorb. ... Water trapped at the surface would become saturated, at which point, the ocean would slow its carbon uptake.
What is the difference between homogeneous and heterogeneous mixtures?
Which statement is not true for a magnetic field?
O A. A magnetic field occurs near a wire that has no current.
OB. A magnetic field is produced by a magnet with two poles.
O c. A magnetic field loops from the north pole to the south pole.
O D. A magnetic field occurs near a current-carrying wire.
Answer:
The answer is letter A.
A. A magnetic field occurs near a wire that has no current.
Because magnetic field occur near a current carrying wire.
Which letter indicates the asthenosphere
Answer:
q
Explanation:
Which two types of energy are formed by the transformation shown in the
photo?
A. Chemical energy
thermal energy
B. Thermal energy -
electrical energy
C. Thermal energy -
chemical energy
D. Chemical energy
-
electromagnetic energy
PREVIOUS
Explanation:
i cant even see any thing
Answer: A and D
Explanation:
What is the energy of a wave if the frequency is 300. Hz
Answer:
[tex]E=1.98\times 10^{-31}\ J[/tex]
Explanation:
Given that,
The frequency of a wave, f = 300 Hz
We need to find the energy of a wave. The formula for the energy of a wave is given by :
E = hf,
Where h is Planck's constant
[tex]E=6.63\times 10^{-34}\times 300\\\\=1.98\times 10^{-31}\ J[/tex]
So, the energy of the wave is [tex]1.98\times 10^{-31}\ J[/tex].
Which of the following is the best definition of a chemical change?
A. A change in a substance where no new substance forms
B. A change in a substance where energy is conserved
C. A change in a substance where a phase change occurs
D. A change in a substance where one or more new substances form
Answer:it's D
Explanation:
A chemical change, unlike a physical change, is the formation of new products or one or more new substances formed from the reactants. Thus, option D is correct.
What is a chemical change?A chemical change is a type of change where the reactants break or combine to form a new product that is different from the reactants. Unlike physical change, they are not reversible and can be seen in combustion, neutralization, decomposition, redox reactions, etc.
It is a change in a matter where the reactant undergoes breaking or forming of the bonds to yield a new product. It is accompanied by changes in temperature, color, precipitation, and odor.
Therefore, a chemical change results in the formation of a new substance.
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Choose the most correct statement from the options below. Be sure to consult the
periodic table.
Magnesium (Mg) and chlorine (Cl) are in the same GROUP and, so, share
SIMILAR physical and chemical properties.
Magnesium (Mg) and chlorine (CI) are in the same PERIOD and, so, share
SIMILAR physical and chemical properties.
Magnesium (Mg) and chlorine (CI) are in the same PERIOD and, so, will have
very DIFFERENT physical and chemical properties.
Magnesium (Mg) and chlorine (CI) are in the same GROUP and, so, share
DIFFERENT physical and chemical properties.
Answer: B
Explanation:
Mg and Cl are in the same row aka period. Elements in the same period have similar properties like electron shells so the second option is the best answer
Most of the mass in an atom is found in the...?
Maybe someone knows how to name compounds by IUPAC ?
Explanation:
The IUPAC system of nomenclature aims to ensure
that every organic compound has a unique, unambiguous name.that the IUPAC name of any compound conveys the structure of that compound to a person familiar with the system.
One way of checking whether the name you have given to an alkane is reasonable is to count the number of carbon atoms implied by the chosen name. For example, if you named a compound 3‑ethyl-4‑methylheptane, you have indicated that the compound contains a total of 10 carbon atoms—seven carbon atoms in the main chain, two carbon atoms in an ethyl group, and one carbon atom in a methyl group. If you were to check the given structure and find 11 carbon atoms, you would know that you had made a mistake. Perhaps the name you should have written was 3‑ethyl-4,4‑dimethylheptane!
plz answer plzplzpzlpl
Molarity to percent by mass. Convert 1.672 mol/L MgCl2(aq) solution to percent by mass of MgCl2 in the solution. The solution density at this concentration is 1.137 g/mL. Answer to 4 significant figures with appropriate units.
Answer:
[tex]\%m/m=14\%[/tex]
Explanation:
Hello!
In this case, since the molarity of magnesium chloride (molar mass = 95.211 g/mol) is 1.672 mol/L and we know the density of the solution, we can first compute the concentration in g/L as shown below:
[tex][MgCl_2]=1.672\frac{molMgCl_2}{L}*\frac{95.211gMgCl_2}{1molMgCl_2}=159.2\frac{gMgCl_2}{L}[/tex]
Next, since the density of the solution is 1.137 g/mL, we can compute the concentration in g/g as shown below:
[tex][MgCl_2]=159.2\frac{gMgCl_2}{L}*\frac{1L}{1000mL}*\frac{1mL}{1.137g}=0.14[/tex]
Which is also the by-mass fraction and in percent it turns out:
[tex]\%m/m=0.14*100\%\\\\\%m/m=14\%[/tex]
Best regards!
What is the most abundant element on Earth?
A oxygen
B Cobalt
C Carbon
D Iron
5
Any substance represented by a chemical formula
A Homogenous mixture
B Heterogenous Mixture
C elements
D pure substance
Answer:
oxygen is the most abundant element on the earth.
How is thermal energy transferred during conduction? Check all that apply.
Thermal energy is transferred hetween particles that are not touching each other.
Thermal energy is transferred between particles that are in direct contact with each other.
Thermal energy is transferred between objects of different temperatures.
Thermal energy is transferred between objects of the same temperature.
Thermal energy is transferred from slow-moving particles to fast-moving particles.
Thermal energy is transferred from fast-moving particles to slow-moving particles.
Answer:energy
Explanation:needed points sorry
PLS HELP ME FOR BOTH QUESTIONS
Answer:
IF the match is stuck on the side it could chach burning hot.
2) the burn peices looks like its burned and it becomes black since of it.
Explanation: