Answer:
It emits 1.64 x 10⁻¹⁸J of energy
Explanation:
The n = 1 is a lower quantum level compared to n = 2.
When a hydrogen atom moves from a higher level to a lower one, it simply emits the energy difference between the two levels.
If a hydrogen atom moves from a lower energy level to a higher one such as from 1 to 2, they absorb the energy difference to attain the new excited state. So, for an electron in the hydrogen atom to move from a higher energy level to a lower one, it must emit 1.64 x 10⁻¹⁸J of energy.In the third century B.C., King Hieron of Syracuse asked the famous mathematician Archimedes to determine if his crown was made of pure gold. This was a puzzling problem for Archimedes-he knew how to measure the weight of the crown, but how could he measure the volume? Archimedes solved the problem when he got into his bath and noticed the water spilling over the sides of the tub. He realized that the volume of the displaced water must be equal to the volume of the object placed into the water. Archimedes was so excited by. his discovery that he jumped out of the bath and ran through the streets shouting "Eureka!" a. How can you tell if a crown is made of solid gold? b. Gold is one of the densest substances known, with a density of 19.3 g/mL. If the gold in the crown was mixed with a less-valuable metal like bronze or copper, how would that affect its density? c. What is the relationship between the object density, the liquid density, and the tendency of the object to float? d. From the experimental results obtained by you in the lab of the density of the liquid and the object, could the object float in that liquid? Explain.
Answer:
See explanation
Explanation:
a. I can conclusively tell if the crown was made of gold by measuring its density. First the mass of the crown is measured on a weighing balance. The crown is now put into a given volume of water and the volume of water displaced is accurately measured. The density of the crown is computed as mass/volume of fluid displaced. If the density of the crown is 19.3 g/mL, then it is made of solid gold.
b) When less valuable metals such as bronze or copper is mixed with gold in the crown, the density of the crown decreases and the crown becomes more brittle.
c) An object will float in a liquid when the density of the object is less than the density of the liquid. Hence the tendency of an object to float in a liquid depends on the density of the object and the density of the liquid.
d) Even though i do not know the results from your experiment but as regards the decision as to whether the object will float in the given liquid or not, reference must be made to the measured density of the object as well as the given density of the liquid. If the object is less dense (from values of density obtained from the experiment) than the liquid, then the object will float in the liquid and vice versa.
What is the concentration of chloride ions in a solution that contains 0.375 g of aluminum chloride in 15.0 mL of solution?
Answer:
0.561 M
Explanation:
Step 1: Given data
Mass of aluminum chloride (m): 0.375 gMolar mass of aluminum chloride (M): 133.34 g/molVolume of the solution (V): 15.0 mLStep 2: Calculate the molar concentration of aluminum chloride (C)
We will use the following expression.
[tex]C = \frac{m}{M \times V(L) } = \frac{0.375g}{133.34 g/mol \times 0.0150L } = 0.187M[/tex]
Step 3: Write the reaction of dissociation of aluminum chloride
AlCl₃(aq) ⇒ Al³⁺(aq) + 3 Cl⁻(aq)
Step 4: Calculate the concentration of chloride ions
The molar ratio of AlCl₃ to Cl⁻ is 1:3. The concentration of Cl⁻ is 3/1 × 0.187 M = 0.561 M
PLEASE HELP!!!!
what happens when the ocean reaches it’s saturation level of carbon dioxide?
Hi!
When the ocean reaches its saturation level of carbon dioxide, a couple of things will happen:
First, more carbon dioxide will remain in the atmosphere, and second, the ocean's pH will drop.
Carbonate and bicarbonate ions in seawater act as a buffer system which keeps the ocean's pH levels stable. When CO2 dissolves in seawater, it reacts with the ocean's buffer system in such a way that it produces two hydrogen ions, which lowers the pH. As more and more CO2 reacts with the ocean's buffer system and the system becomes saturated, less atmospheric carbon dioxide will cross over into the ocean. This excess CO2 will remain in the atmosphere and contribute to global climate change.
Hope this helped!
When the ocean reaches it's saturation level of carbon dioxide more amount of carbon dioxide remains in the atmosphere and pH of the ocean drops.
What is saturation level?It is defined as the level or extent up-to which a substance is soluble in a particular solvent. Due to global warming ,there is an excessive release of carbon dioxide in atmosphere. The excessive amount cannot be soluble in the ocean water which leads to ocean acidification.
As a result of ocean acidification the pH of water in the ocean drops thus there is less amount of oxygen present for aquatic organisms which is needed to survive. When carbon dioxide dissolves in water it yields carbonic acid which further reduces the pH of water and thus making it unfit for aquatic environment.
Learn more about saturation level,here:
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Blood takes about 1.55 s to pass through a 2.00 mm long capillary. If the diameter of the capillary is 5.00 μm and the pressure drop is 2.45 kPa, calculate the viscosity ???? of blood. Assume laminar flow.
Answer:
The viscosity [tex]\mathbf{\eta = 7.416 \times 10^{-4} \ N.s/m^2}[/tex]
Explanation:
From the given information:
Time t = 1.55 s
The radius of capillary = 5.00 μm /2
The pressure drop ΔP = 2.45 kPa
The length of the capillary = 2.00 mm
∴
The viscosity of the blood flow can be calculated by using the formula:
[tex]\eta = \dfrac{r^2 \Delta P }{8Lv}[/tex]
where;
v = L/t
Then;
[tex]\eta = \dfrac{r^2 \Delta P }{8L(\dfrac{L}{t})}[/tex]
[tex]\eta = \dfrac{(\dfrac{5 \times 10^{-6} \ m}{2})^2(2.45 \times 10^3 \ Pa) }{8(2.0 \times 10^{-3} \ m ) (\dfrac{2.0 \times 10^{-3} \ m }{1.55 \ s })}[/tex]
[tex]\eta = 7.416 \times 10^{-4} \ Pa.s[/tex]
To (N.s/m²)
[tex]\mathbf{\eta = 7.416 \times 10^{-4} \ N.s/m^2}[/tex]
For at least the last century Florida has experienced a hurricane season every year, from June to November. Which of the following describes this occurrence the BEST?
A. Florida's precipitation
B. Florida's global pattern
C. Florida's climate
D. Florida's weather
Answer:
Florida's Global Pattern.
Explanation:
Because of where Florida sits, the weather in the Gulf of Mexico actually blows enough water to Create tidal waves, and also hurricanes. at least that's what I was told cause I live here :>
Of the following, which is NOT a component of the circulatory system?
A. Heart
B. Veins
ws
C. Arteries
D. Brain
Answer:
D. Brain
~PumpkinSpice1
A 1,500 kg truck is towed sideways out of a mud-hole with a force of 15,000 N. What acceleration of the tow truck is needed to move this vehicle?
Does MgO have a structure like that of NaCl or ZnS? If the density of MgO is 3.58g/cm3, estimate the radius (in centimeters) of the O2â anions and of the Mg2+ cations.
Answer:
The radius of O^2- is 1.5*10^-8 cm and the radius of
Mg ^2+ is 6.2*10^-9 cm
Explanation:
Face centered cubic : 1/8 atoms on each edges + 1/2 atoms on each face
= [tex]\frac{1}{8}* 8 + \frac{1}{2}*6[/tex] = 4 effective atoms
MgO have a structure like NaCl forms a lattice of FCC.
density of the lattice = [tex]\frac{ z.M}{a^3*Na}[/tex]
z : no of atoms
M: mass of the atoms
a: radius of the atom
Na: Avogadro's number
a^3(radius) = [tex]\frac{ 4*40.3}{3.58*6.022*10^23}[/tex]
a^3 = 7.477 * 10^-23 cm^3
a = 4.21 * 10^-8 cm
Now calculating the anionic(ra O^2-) and cationic (rc Mg^2+)
in Fcc a = 2[tex]\sqrt{2} ra[/tex]
ra = 1.5*10^-8 cm
a = 2ra + 2rc
rc = a/2 -ra
rc = 6.2*10^-9 cm
The radius of O^2- is 1.5*10^-8 cm and the radius of Mg ^2+ is 6.2*10^-9 cm
Using the equations
2 C₆H₆ (l) + 15 O₂ (g) → 12 CO₂ (g) + 6 H₂O (g)∆H° = -6271 kJ/mol
2 H₂ (g) + O₂ (g) → 2 H₂O (g) ∆H° = -483.6 kJ/mol
C (s) + O₂ (g) → CO₂ (g) ∆H° = -393.5 kJ/mol
Determine the enthalpy (in kJ/mol) for the reaction
6 C (s) + 3 H₂ (g) → C₆H₆ (l).
The enthalpy : 49.1 kJ/mol
Further explanationThe change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation
The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)
Based on the principle of Hess's Law, the change in enthalpy of a reaction will be the same even though it is through several stages or ways
Reaction
1. 2C₆H₆ (l) + 15 O₂ (g) → 12 CO₂ (g) + 6 H₂O (g)∆H° = -6271 kJ/mol
Reverse
12 CO₂ (g) + 6 H₂O (g) ⇒ 2C₆H₆ (l) + 15 O₂ (g) ∆H° = 6271 kJ/mol : 2
6CO₂ (g) + 3H₂O (g) ⇒ C₆H₆ (l) + 15/2 O₂ (g) ∆H° = 3135.5 kJ/mol
2. 2 H₂ (g) + O₂ (g) → 2 H₂O (g) ∆H° = -483.6 kJ/mol x 3/2
3H₂ (g) + 3/2O₂ (g) → 3H₂O (g) ∆H° = -725.4 kJ/mol
3. C (s) + O₂ (g) → CO₂ (g) ∆H° = -393.5 kJ/mol x 6
6C (s) + 6O₂ (g) → 6CO₂ (g) ∆H° = -2361 k/j/mol
-------------------------------------------------------------------------------------
6 C (s) + 3 H₂ (g) → C₆H₆ (l) ∆H° = 49.1 kJ/mol
We add up and the same compound that is on different sides we eliminate
How many electrons does Sodium lose to become an ion
Which two bonds are most similar in polarity? Which two bonds are most similar in polarity? O-F and Cl-F B-F and Cl-F I-Br and Si-Cl Al-Cl and I-Br C-Cl and Be-Cl
Answer:
A
Explanation:
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The branch of science which deals with chemicals and bonds is called chemistry.
The correct answer is A.
The polarity is defined as the separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end.
The polar molecule has the following:-
Difference in electronegativity.In, the first compound the polarity is the same because the compound is the same that is O-F and CL-F.
Hence, the correct answer is A.
For more information, refer to the link:-
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Dinitrogen tetraoxide, a colorless gas, exists in equilibrium with nitrogen dioxide, a reddish brown gas. One way to represent this equilibrium is:
The question is incomplete, the complete question is shown in the image attached
Answer:
F
T
Explanation:
From the equilibrium equation;
N2O4(g) ⇄NO2(g)
We must have to remember that;
1) At equilibrium, the concentration of the species on both sides of the reaction equation may not necessarily be the same but must be held at a constant value because the rate of forward reaction equals the rate of reverse reaction.
2) The rate of forward reaction must equal the rate of reverse reaction.
If the rate of forward reaction is k1 and the rate of reverse reaction is k2. Then it follows that at equilibrium k1 = k2.
PLease help me I am giving a lot of points for this please help me
Answer:
Under balanced its motion under motion its s = d/t under s - d/t is time d = distance s= speed
Explanation:
how many moles of Na2SO4 are in 0.140 m aqueous solution that was prepared with 2.30 kg of water?
Answer:
0.322 mols of NaSO4
Explanation:
Molality = Mols of Solute / kg of Solvent
Molality is given as 0.140 m = mols/kg
kg of solution is given as 2.30 kg
Mols of Solute = Molality * kg of Solvent
Mols of Solute = [tex]\frac{0.140 }{ 1 kg } *2.30 kg[/tex]
Mols of Solute = 0.322 mols
The number of mole of Na₂SO₄ required to prepare the solution is 0.322 mole
The Molality of a solution is defined as the mole of solute per Kg of water i.e
Molality = mole / mass (Kg) of water.
With the above formula, we can obtain the mole of Na₂SO₄ in the solution as follow:
Molality of Na₂SO₄ = 0.140 M
Mass of water = 2.30 Kg
Mole of Na₂SO₄ =.?Mole = Molality × mass of water
Mole of Na₂SO₄ = 0.140 × 2.30
Mole of Na₂SO₄ = 0.322 moleTherefore, the mole of Na₂SO₄ in the solution is 0.322 mole
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What does the word subcellular mean
Answer:
the word subcellular means contained within a cell. at a level of organization lower than the cellular.
Explanation:
What happens when this match is struck against the side of the match box?
Answer:
It lights on fire
Explanation:
The friction sparks the match causing it to go on fire.
Why can’t you ice skate on a lake when it is not frozen?
A student combines a sample of gas (2.0 L) at 3.5 atm with with another gas (1.5 L) at 2.8 atm pressure into an empty 7.0 L flask. Assuming the gases are combined at constant temperature, what is the total gas pressure (in atmospheres) in the 7.0 L flask?
Answer:
Total gas pressure is 1.60 atm
Explanation:
To solve this question we can use the Ideal Gases Law. We need to determine how many moles of each gas will be finally present at the flask of 7 L.
Let's asume the gas, are at Asbsolute T°, 273K
P. V = n . R . T
3.5 atm . 2L = n . 0.082 . 273K
(3.5 atm . 2L) / (0.082 . 273K) = 0.313 moles
(2.8 atm . 1.5L) / (0.082 . 273K) = 0.188 moles
Total moles = 0.313 mol + 0.188 mol = 0.501 mol
Let's calcualte the hole pressure
P . 7L = 0.501 moles . 0.082 . 273K
P = (0.501 moles . 0.082 . 273K) / 7L → 1.60 atm
What is 50% of 36?
O 9
O 16
O 18
O 34
Answer:
18
Explanation:
36 times 0.5
Describe the three kinds of particles found in atoms. Where are they located in the atom and what are their charges?
A student is preparing for the titration of 20.0 mL of an approximately 0.3 M solution of NH3 using HCl . She has a 50.0 mL buret and four possible HCl solutions to fill it with. Which solution would be best for use in her titration?a. 6.00 M HCI(aq) b. 0.3 M HCI(aq) c. 0.200 M HCI(aq) d. 0.100 M HCl(aq)
Answer:
c. 0.200 M HCI(aq)
Explanation:
The titration of a base as NH3 with hydrochloric acid is:
NH3 + HCl → NH4Cl
Where 1 mole of NH3 reacts per mole of HCl
The recommended volume to read in a burette is between 60 and 80% of its capacity.
That is 60% 50.0mL = 30mL and 80% 50.0mL = 40mL must be spent.
A 6.00M HCl spend:
20mL * (0.3mol/L) * (1L/ 6.00M) = 1mL. This solution is not the ideal for the titration.
A 0.3M HCl spend:
20mL * (0.3mol/L) * (1L/ 0.3M) = 20mL. This solution is not the ideal for the titration.
A 0.200M HCl spend:
20mL * (0.3mol/L) * (1L/ 0.200M) = 30mL. This solution ideal for the titration.
A 0.100M HCl spend:
20mL * (0.3mol/L) * (1L/ 0.100M) = 60mL. This solution is not the ideal for the titration.
Right option is:
c. 0.200 M HCI(aq)An ideal gas had a mass of 0.0218g and occupied a volume of 1.111L at 0oC and 0.0100atm. What is the molar mass of this gas?
Answer:
Explanation:
we shall use gas law formula to solve the problem .
P = .01 atm
V = 1.111 L
T = 273 K
mass of gas = .0218
molar mass = M
no of moles n = .0218 / M
PV = n RT
.01 x 1.111 = (.0218 / M) x .082 x 273
.0218 / M = .000496
M = .0218 / .000496
= 43.95
Based on molecular orbital theory, the only molecule in the list below that has unpaired electrons is __________.a) C2b) N2c) F2d) O2e) Ne2
Answer:
B.
Explanation:
ive done this before trust
amu.
An atom with 4 protons, 5 neutrons, and 4 electrons has an atomic mass of
(Enter a whole number.)
Answer:
Explanation:
the sum of number of proton and neutron is known as atomic mass
so if number of proton is 4 and neutron is 5 then atomic mass of an atom is 9
what is the molecular geometry of c atom in ch3nh2
Answer:
compound is sp3.
Explanation:
Redox reactions stand for oxidation/reduction reactions. True or false: an oxidation reaction is always paired with a reduction reaction.
Answer:
The answer is: true
Explanation:
In redox reactions, the half-reactions of oxidation and reduction always occur simultaneously in pair.
The oxidation half-reaction involved the lost of electrons from a reduced substance (A) to form a oxidized substance (A⁺):
A ⇒ A⁺ + e-
In contrapossition, during the reduction half-reaction the oxidized substance (B⁺) gains electrons to form the reduced subtance (B):
B⁺ + e- ⇒ B
The overall redox reaction is obtained by the addition of the two half-reactions:
A ⇒ A⁺ + e-
B⁺ + e- ⇒ B
-----------------
A + B⁺⇒ A⁺ + B
The electrons gained by B are provided by A, which lost the same number of electrons. Thus, the oxidation/reduction reactions are paired.
2 or more forces that are not equal and opposite of one another can cause change in motion
A. Balanced force
B.friction
C.gravitational force
D.unbalanced force
Answer:
D unbalanced force
Explanation:
i think
How many different E2 products are expected in the reaction of 3-bromo-1,1-dimethylcyclohexane with NaOCH2CH3?
A) only 1
B) 2
C) 3
D) 4
The temperature of a sample of CH4 gas (10.34 g) in a 50.0 L vessel at 1.33 atm is ________ °C.
a.
984
b.
-195
c.
-1260
d.
-195
Answer:
option C is correct
Explanation:
Considering the ideal gas law and the definition of Avogadro's Number, the correct option is option a. The temperature of a sample of CH₄ gas (10.34 g) in a 50.0 L vessel at 1.33 atm is 984 °C.
In first place, you have to know that ideal gases are a simplification of real gases that is done to study them more easily.
It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T).
The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:
P×V = n×R×T
In this case, being the molar mass of CH₄ being 16 [tex]\frac{g}{mole}[/tex], that is, the mass present in one mole of an element or compound, the number of moles that 10.34 grams contains is calculated as:
[tex]10.34 g*\frac{1 mole}{16.04 g} = 0.645 moles[/tex]
So, you know:
P= 1.33 atmV= 50 Ln= 0.645 molesR=0.082 (atm×L)/ (mol×K)T= ?Replacing:
1.33 atm × 50 L= 0.645 moles× 0.082 (atm×L)/ (mol×K) ×T
Solving:
T= [1.33 atm × 50 L] ÷ [0.645 moles× 0.082 (atm×L)/ (mol×K) ]
T≅ 1257 K
Being 273 K equivalent to 0 C, then:
T= 1257 K= 984 C
In summary, the correct option is option a. The temperature of a sample of CH₄ gas (10.34 g) in a 50.0 L vessel at 1.33 atm is 984 °C.
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1. Change the following into correct scientific notation.
a) 0.03050 =
b) 0.256 x 10°=
c) 25.005 10 =
Answer:
a) 0.03050 = 3.050 × 10-²
b) 0.256 x 10°= 2.56 × 10-¹
c) 25.005 10 = 2.500510 × 10¹
Explanation:
Scientific notations is a way of making very large or very small numbers more comprehensive or simplified. It involves the use of power of ten (10^). The numbers are represented to the power of ten. The following format is used:
a x 10^b
where; a is a number or decimal number between 1 and 10 i.e less than 10 but greater than 1
b is the power of ten
To write a number in scientific notation,
- we move the decimal point right or left depending on whether we're trying to reduce or increase the number
- we count the number of times the decimal point was moved. This serves as the b in the format above.
For example,
a) 0.03050 = 3.050 × 10-²
The decimal point was moved rightward twice. This caused the ^-2 power.
b) 0.256 x 10°= 2.56 × 10-¹
The decimal point was moved rightward once. This caused the ^-1 power.
c) 25.005 10 = 2.500510 × 10¹
The decimal point was moved leftward once. This caused the ^1 power.