Answer:
Explanation:
Distilled water has a pH of 7. Anything below that is acidic. One is very acidic. So a b and c cannot be the answer.
Lime is a base. That means that when it is put in water, the pH is going to be greater than 7,
The only possible answer is D
Which is the electron configuration for bromine?
Answer:
bromine atomic number =35
1s²2s²2p^6 3s² 3p^6 4s² 3d^10 4p^5.
) The atomic number of magnesium is 12.
Magnesium exists as three isotopes; Magnesium-24, Magnesium-25 and Magnesium 26.
Describe, by reference to the numbers of subatomic particles, the differences between one atom of
each of these isotopes.
(2)
Answer: The difference between these 3 isotopes is the number of neutrons.
The atomic mass of an atom is the number of protons plus neutrons. We know that the atomic number of magnesium is 12, so therefore there are 12 protons.
In Magnesium-24, there are 24-12 neutrons = 12 neutrons.
In Magneusium-25, there are 25-12 neutrons = 13 neutrons
In Magnesium-26, there are 26-12 neutrons = 14 neutrons
an unknown gas at constant temperature, has a pressure of 2 atm and a volume of 7 L. Calculate the final pressure if the volume drops to 0.7 L.
At constant temperature, if the volume of the unknown gas drops to the given value, the pressure increases to 20.0atm.
Given the data in the question;
Initial volume of the unknown gas; [tex]V_1 = 7L[/tex]Initial pressure of the unknown gas; [tex]P_1 = 2atm[/tex]Final volume of the unknown gas; [tex]V_ 2 = 0.7L[/tex]Final pressure of the unknown gas; [tex]P_2 = \ ?[/tex]
Boyle's lawBoyle's law simply states that the volume V of any given quantity of gas is inversely proportional to its pressure P as long as temperature remains constant.
Boyle's law is expressed as;
[tex]P_1V_1 = P_2V_2[/tex]
Where [tex]P_1[/tex] is Initial Pressure, [tex]V_1[/tex] Initial volume, [tex]P_2[/tex] is Final Pressure and [tex]V_2[/tex] is Final volume.
We substitute our given values into the expression above to determine the final pressure.
[tex]P_1V_1 = P_2V_2\\\\P_2 = \frac{P_1*V_1}{V_2} \\\\P_2 = \frac{2atm\ * 7L}{0.7L} \\\\P_2 = \frac{2atm\ * 7}{0.7}\\\\P_2 = \frac{14atm}{0.7}\\\\P_2 = 20.0atm[/tex]
Therefore, at constant temperature, if the volume of the unknown gas drops to the given value, the pressure increases to 20.0atm.
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4) Find the mass of 1.46 mol of Al2(SO4)3.
Answer:
1.46mol of Al2(SO4)3 weights 499.5 grams
Explanation:
First we will find the gram formula mass of Al2(SO4)3.
Al * 2 = 26.98 g/mol * 2 = 53.96 g
SO4 * 3 = 96.06 g/mol * 3 = 288.18
53.96 + 288.18 = 342.14 g
That is the mass of 1 mol of AL2(SO4)3.
Now we will multiply 342.14g by 1.46.
342.14 * 1.46 = 499.5244 g
Or ... 499.5 g
A sample contains 2.2 g of the radioisotope niobium-91 and 15.4 g of its daughter isotope, zirconium-91.
If the half-life of niobium-91 is 680 years, how long will it take for the decay described in the previous question?
680 years
1,360 years
✓2,040 years (correct answer)
2,720 years
Time to decay : 2040 years
Further explanation
The atomic nucleus can experience decay into 2 particles or more due to the instability of its atomic nucleus.
Usually radioactive elements have an unstable atomic nucleus.
The main particles are emitted by radioactive elements ,so that they generally decay, are alpha (α), beta (β) and gamma (γ) particles
General formulas used in decay:
[tex]\tt Nt=No.\dfrac{1}{2}^{\dfrac{T}{t\frac{1}{2} }[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
moles zirconium :
[tex]\tt \dfrac{15.4}{91}=0.169[/tex]
moles niobium :
[tex]\tt \dfrac{2.2}{91}=0.0242[/tex]
the half-life of niobium-91 is 680 years
Reaction
⁹¹₄₁Nb ⇒⁹¹₄₀Zr + ₁⁰e
Amount of Nb from reaction : 0.169
Amount of initial Nb = 0.0242 + 0.169 = 0.1932
Time to decay (T) :
[tex]\tt 0.0242=0.1932.\dfrac{1}{2}^{\dfrac{T}{680}}\\\\0.1252=\dfrac{1}{2}^{\dfrac{T}{680}}\\\\\dfrac{1}{2}^{3}=\dfrac{1}{2}^{\dfrac{T}{680}}\\\\T=680\times 3=2040[/tex]
Answer:
It’s CCCCCCCCCCCCCCC
Explanation:
I just took the instruction and yes its “C.”
PLEASE ANSWER AND I WILL GIVE BRAINLIEST! THE ANSWER IS NOT B
Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below.
A large black cross in a purple circle with a black line around the purple, with 10 small green balls dispersed within the purple circle.
What experimental evidence led to the development of this atomic model from the one before it?
A. A few of the positive particles aimed at a gold foil seemed to bounce back.
B. The colors of light emitted from heated atoms had very specific energies.
C. Equations were used to identify regions around the nucleus where electrons would likely be.
D. Cathode rays were bent in the same way whenever a magnet was brought near them.
Answer:
A
Explanation:
It says it in the videos my sister watch on Edgenuity. A few of the positive particles aimed at a gold foil seemed to bounce back. If you take notes it says it. (ps. I am not trying to be mean I am just saying- no hurt feelings?)What is Aurora Borealis?
Auroras present in polar regions.
Answer:
the Northern Lights
Explanation:
The northern lights, one of several astronomical phenomena called polar lights (aurora polaris), are shafts or curtains of colored light visible on occasion in the night sky. Aurora borealis
hope this helps
Hell me ASAP please
60 points! please help me! will appreciate it!
Answer:
[tex]\huge\boxed{\sf 49.41\ L}[/tex]
Explanation:
In the reaction:
for every 3 moles of H₂, 2 moles of NH₃ are produced.
Converting 25 g of Ammonia into moles:
Moles = mass / molar mass
= 25 / (14 + 1 × 3)
= 25 / (14 + 3)
= 25 / 17
= 1.47 mol
From the reaction:
2 NH₃ = 3 H₂
1 NH₃ = 3/2 H₂
1 NH₃ = 1.5 H₂
1.47 mol of NH₃ = 1.5 × 1.47 mol of H₂
1.47 mol of NH₃ = 2.2 mol of H₂
So, 2.2 mol of H₂ are needed to produce 1.47 mol (25 g) of NH₃
Converting 2.2 mol of H₂ into L:
= mole × molar value
[molar value = 22.4 L/mol]
= 2.2 × 22.4
= 49.41 L
[tex]\rule[224]{225}{2}[/tex]
The standard reduction potentials for two half-cells involving iron are: given below. Fe2+ (aq) + 2e– ® Fe (s) Eο = –0.44 V Fe3+ (aq) + e– ® Fe2+ (aq) Eο = +0.77 V What is the equation and the cell potential for the spontaneous reaction that occurs when the two half-cells are connected?
Answer:
Explanation:
Fe⁺² (aq) + 2e⁻ = Fe (s) ; E⁰ = - .44 V
Fe⁺³ (aq) + e⁻ = ® Fe²⁺ (aq) ; E⁰ = + .77 V
Reduction potential of second reaction is more , so it will take place , ie Fe⁺³ will be reduced and Fe will be oxidised .
So reaction in the combined cell will be
2Fe⁺³ + Fe = 3Fe⁺²
cell potential = .77 - ( - .44 )
= 1.21 V .
round 42,561 to 4 significant figures
Answer:
4,256
if not that then 42,560
Explanation:
What is the concentration, in grams per liter, of a solution prepared by dissolving 0.00040 mol hcl in 2.2 l h2o? assume that the volume of the solution does not change when the hcl is added. g/l
The concentration, in grams per liter, of a solution prepared by dissolving 0.00040 mol HCl in 2.2L H₂O is 0.0066 g/L.
How we calculate mass from moles?Mass of any substance will be calculated by using their moles as:
n = W/M, where
W = required mass
M = molar mass
GIven moles of HCl = 0.00040 mole
Mass of 0.00040 mole of HCl will be calculated as:
W = (0.00040mol)(36.45g/mol) = 0.01458g
Given volume of Water = 2.2 L
Now the concentration in molality (g/L) will be calculated as:
concentration = (0.01458g) / (2.2L) = 0.0066 g/L.
Hence required concentration is 0.0066 g/L.
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Answer: first one is 0.0066 and second one is 6.6
Explanation:
I got it right
Decide if these characteristics belong to the Protons, neutrons or Electrons.
1) They spin around the nucleus. _____
2) They are located in the orbits. _____
Answer:
1)electrons
2)protons, neutrons
Explanation:
please mark me as brainlest
Answer:
1 . c
2. a , b
Explanation:
1 . the electrons spin around the nucleus of an atom
2. the protons and neutrons are located in the orbit of an atom
What’s the answers ???
Answer:
1.potential
2. Kinetic
3. Potential
4. I think is potential because it is storing the energy but if is a crank flashlight it is kinetic.
Explanation:
Gasoline, if 9.00 liters has a mass of 6120 g. Find the density in g/cm^3
Answer:
The density of gasoline is 0.68 g/cm³.
Explanation:
Given data:
Volume of gasoline = 9.00 L
Mass of gasoline = 6120 g
Density of gasoline = ?
Solution:
first of all we will convert the unit, L to mL.
9.00 L × 1000 mL / 1 L = 9000 mL
Formula:
d = m/v
d = density
m = mass
v= volume
d = 6120 g/ 9000 mL
d = 0.68 g/cm³ ( mL =cm³ )
Thus, density of gasoline is 0.68 g/cm³ .
Which type of energy warms Earth’s surface?
Answer:
infared radiation
Explanation:
Answer:
infared radiation
Explanation:
Nitrogen gas and hydrogen gas react to produce ammonia according to the following equation.
N2 + 3H2 → 2NH3
Which ratio of components is correct?
A For every mole of hydrogen gas, the reaction produces 2 moles of ammonia.
B For every 3 moles of hydrogen gas, the reaction produces 2 moles of ammonia.
C For every 2 moles of nitrogen gas, the reaction requires 3 moles of hydrogen gas.
D For every mole of nitrogen gas, the reaction produces 1 mole of ammonia. ***
The answer will be for every 3 moles of hydrogen gas, the reaction produces 2 moles of ammonia.
What will be the ratio of nitrogen and hydrogen to produce ammonia?
For making ammonia one mole of nitrogen gas is combined with the three moles of hydrogen gas to produce two moles of ammonia.
The ratio of nitrogen, hydrogen, and ammonia is as follows 1:3:2. now if we need to produce 10 moles of ammonia for the balanced equation the ratio will become 10:30:20.
The reaction is as follow:-
[tex]\rm N_2+3H_2----- > 2NH_3[/tex]
For nitrogen
[tex]\rm N_2--- > 1\ Molecule \\\rm N_2--- > 1\ Mole\\\rm N_2--- > 28.02\ g[/tex]
For Hydrogen
[tex]\rm H_2--- > 3\ Molecules\\\rm H_2--- > 3\ Moles\\ \rm H_2--- > 3\times2.02--- > 6.06\ g[/tex]
For Ammonia
[tex]\rm NH_3--- > 2\ Molecules \\\rm NH_3--- > 2\ Moles\\\rm NH_3--- > 2\times17.04--- > 34.08\ g[/tex]
Thus the answer will be for every 3 moles of hydrogen gas, the reaction produces 2 moles of ammonia.
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Answer:
B For every 3 moles of hydrogen gas, the reaction produces 2 moles of ammonia.
Explanation: I just did it
Which of the following is an ozone depleting substance (ODS)?
a.
ultraviolet radiation
b.
chlorofluorocarbon (CFC)
c.
biogeochemical cycle
d.
none of the above
Answer:
b
Explanation:
In an ecosystem, the ozone depleting substance is chlorofluorocarbon or the CFC's.
What is an ecosystem?Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the ecosystem through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.There are different types of ecosystems.
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For an atom (which is neutral), which of these must be
true?
The number of protons is equal to the number of electrons
The atomic number is equal to the mass number
The number of electrons is equal to the number of neutrons
The number of protons is equal to the number of neutrons
Answer:
The number of protons is equal to the number of electrons
Explanation:
For an atom to be neutral, all the charges have to equal zero. Because protons are charged +1 and electrons are charged -1, the number of protons has to be equal to the number of electrons for the charges to cancel out.
TRUE or FALSE. Write I If the statement is TRUE, write F if the statement is
FALSE on the space provided before the number.
1. A mixture is always made up of a combination of elements
2. A mixture is not a chemical combining of substances
3. In a mixture, the substances lose their identities
4. The substances involved in a mixture cannot be separated by a simple physi
process
5. Salt and water can be separated through distillation
6. Water for drinking can only be obtained from seawater by distillation
7. The distillation of miscible liquids is only possible if the liquids have differ
boiling points.
8. Mixtures have fixed melting and boiling points.
9. Paper chromatography is a physical method for separating mixtures
10. Crude oil is broken down by heat, vaporized, and allowed to condense
various liquids such as gasoline. This process is called distillation
PLEASE HELP ASAP The concentration of a solution is equal to the mass of solute divided by the volume of solvent. Units of concentration are grams per 100 milliliters, g/100 mL. You add 12g of sugar to 100 mL of water. What is the concentration?
. 12 g/100mL
12 g/100mL
12g
120g
Answer:
120 g is the answer I think
Explain the process of how James Chadwick
found the neutron.
Answer:
In 1932, the physicist James Chadwick conducted an experiment in which he bombarded Beryllium with alpha particles from the natural radioactive decay of Polonium. The resulting radiation showed high penetration through a lead shield, which could not be explained via the particles known at that time.
Explanation:
What mass of sugar C12H22O11 is required to provide 2.50 x 1023 molecules of O2?
The law of conservation of matter tells us that the total number of atoms does not change in a chemical reaction and thus mass is conserved. Select ALL of the reactions that obey the law of conservation of matter. A) 4 NH3 + 5 O2 → 4 NO + 6 H2O B) 8 H2S + 8 Cl2 → S8 + 16 HCl C) CH4 + 2 O2 → CO2 + H2O D) HCl + K2CO3 → KCl + H2O + CO2 E) 2 Al(OH)3 + 3 H2SO4 → Al2(SO4)3 + 6 H2O
A B & E
If you look at the balancing you'll see that C & D are balanced incorrectly.
The reactions A, B, and E follow the law of conservation of mass. So the correct options are A, B, and E.
What is the law of conservation of mass?According to the rule of conservation of mass, matter cannot be generated or destroyed in a closed or isolated system. It is preserved yet capable of changing forms.
The rule of conservation of mass, which applies to the study of chemistry, states that the mass of the reactants and products in a chemical reaction must be equal.
To be clear: A system that is isolated from its environment is one that does not interact with it. As a result, no matter what changes or chemical reactions take place in that isolated system, the mass will remain constant; even if the final state may differ from the initial state, there can be no more or less mass than there was before the change or reaction.
Therefore the correct options are A, B, and E.
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A sample of substance X is found to be an element with the atomic number 13.
Which atomic number below represents an element that shares similarities with
substance X?
A.3
B.5
C.22
D.33
(i think it’s b but i’m not sure)
Atoms of different element can not have same atomic number because only same type of atoms combine to form element. Atoms belonging to different element can have different atomic number. Therefore, the correct option is option B.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same. Two or more than two atoms with different physical or chemical properties can not combine together to form an element.
Element with atomic number 13 represents aluminium element. The element that belongs to aluminium family will have same property as aluminium. Boron is a element that have same property as aluminium.
Therefore, the correct option is option B.
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Small quantities of hydrogen and helium gas at the same temperature are released simultaneously at one end of a laboratory. State with reason which gas is more likely to be detected at the other end.
Answer:
hydrogen
Explanation:
it diffuses faster compared to helium since it is less dense
Answer:
Hydrogen
Explanation:
It is lighter than helium
Raisin bran is a
O homogenous mixture
O compound
O heterogeneous mixture
O element
Answer:
It is a heterogeneous mixture
URGENT
What do electrochemical cells use to generate electricity?
Question 1 options:
Flow of protons
Flow of neutrons
Flow of electrons
Flow of particles
Answer:
flow of electrons between the electrolytes and the electrodes
A scuba diving tank at a pressure of 180 atmospheres contains a mixture of three gases: oxygen, helium, and nitrogen. The partial pressures of the oxygen and helium are 81 atmospheres and 58 atmospheres, respectively. What is the partial pressure of nitrogen in the tank?
Considering the Dalton's partial pressure, the partial pressure of nitrogen in the tank is 41 atm.
Dalton's partial pressureThe pressure exerted by a particular gas in a mixture is known as its partial pressure.
So, Dalton's law states that the total pressure of a gas mixture is equal to the sum of the pressures that each gas would exert if it were alone:
[tex]P_{T} =P_{1} +P_{2} +P_{3} + ... +P_{n}[/tex]
where n is the amount of gases present in the mixture.
This relationship is due to the assumption that there are no attractive forces between the gases.
In summary, the total pressure in a mixture of gases is equal to the sum of partial pressures of each gas.
Partial pressure of nitrogenIn this case, the total pressure of the gas mixture is calculated as:
[tex]P_{T} =P_{oxygen} +P_{helium} +P_{nitrogen}[/tex]
You know that:
[tex]P_{T} = 180 atm[/tex][tex]P_{oxygen} = 81 atm[/tex][tex]P_{helium} = 58 atm[/tex][tex]P_{nitrogen}= ?[/tex]Replacing in the expression for the total pressure:
[tex]180 atm=81 atm+58 atm+P_{nitrogen}[/tex]
Solving:
180 atm -81 atm -58 atm= [tex]P_{nitrogen}[/tex]
41 atm= [tex]P_{nitrogen}[/tex]
Finally, the partial pressure of nitrogen in the tank is 41 atm.
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60 points please help me i would appreciate it!
Answer:
[tex]\huge\boxed{\sf 39\ L}[/tex]
Explanation:
In the reaction:
for 1 mol of propane, 3 moles of CO₂ are produced.
Volume of propane = 13 L
At STP,
1 mol of propane = 22.4 L/dm³ molar value
So,
Moles in 13 L of propane:
= volume / molar volume
= 13 / 22.4
= 0.58 mol
Since,
1 mol of propane = 3 moles of CO₂
0.58 mol of propane = 3 × 0.58 mol of CO₂
0.58 mol of propane = 1.74 mol of CO₂
Converting 1.74 mol of CO₂ into L:
[Multiply it by 22.4 L/mol]
= 1.74 mol × 22.4 L/mol
= 39 L
[tex]\rule[225]{225}{2}[/tex]