Answer:: A photovoltaic cell converts light into electrical energy. Suppose a certain photovoltaic cell is only 63.5% efficient, in other words, that 63.5% of the light energy is ultimately recovered. If the energy output of this cell is used to heat water, how many 520 nm photons must be absorbed by the photovoltaic cell in order .
Explanation:
Winds move in the same direction in both southern and northern hemispheres.
Select one:
True
False
Answer:
your answer would be false.
Explanation:
prevailing winds blow east-west rather than north-south.
How do you know about a substance if you know its temperature
A. How heavy the substance is
B. How large or small the particles of the substance are
C. How hot or cold the substance is
D. How many particles are in the substance
Answer:
How hot or cold the substance is
Explanation:
You can do a lot with just the temperature of a substance. Chemists can use this to identify the substance because of the temperature at which it melts. They can then find out how long it took to melt, which can also help.
Answer:c how hot or cold
Explanation:
When an atom of oxygen forms an ion, what is the most likely charge for that ion?
a. -2
b. -8
C. +2
d. -6
Answer:
b option is the answer.
Answer:
-2
__________________________________________________________
How many electrons does Oxygen need:
We know that oxygen has an electric configuration of:
2 , 6 [8 electrons]
From the octet rule, we know that all elements try to get to the electronic configuration of the nearest noble gas
In the case of Oxygen, the nearest noble gas is Neon with the electronic configuration:
2 , 8 [10 electrons]
From the above, we can see that oxygen needs 2 more electrons in order to attain the nearest noble gas configuration
What will be the Charge on the ion?:
We know that electrons are negatively charged
Once oxygen gains 2 electrons to attain noble gas configuration, it will have 2 more electrons than it should have
So, the charge on the ion will be -2 since there are 2 extra electrons and both of the electrons contribute a negative charge
Hence, the charge is -2
What is the charge of an atom that has 6 protons, 4
neutrons, and 6 electrons?
Answer:
neutral/no charge
Explanation:
WILL GIVE BRAINLIEST!
Calculate the bond for CO2
Answer:
Bonding Order = number of bonding electrons – number of antibonding electrons/2.
So for CO2, there is a total of 16 electrons, 8 of which are antibonding electrons.
So 16 – 8 = 8; divided by 2 = 4. So, 4 is the bonding order of CO2. The molecular structure of CO2 looks like this:
..~-~~..
O=C=O
..~-~~..
How many milliliters of an aqueous solution of 0.227 M sodium carbonate is needed to obtain 3.55 grams of the salt?
Answer:
147.6 mL .
Explanation:
sodium carbonate , Na₂CO₃
Molecular weight = 106
3.55 gm of sodium carbonate = 3.55 / 106
= .0335 moles
Let the volume of litre required = V
V litre of .227 M solution will contain
V x .227 moles of sodium carbonate . So
V x .227 = .0335
V = .1476 L
= 147.6 mL .
Which formula is an ionic compound?
CO2
NaF
N2
NO2
Answer:
def CO2
Explanation:
What must be true about two objects for conduction to take place?
The objects must be different temperatures and they must be in contact.
The objects must be the same temperature and they must be in contact
The objects must be different temperatures and they must be insulators.
O The objects must be the same temperature and they must be insulators.
Answer:
The objects must be different temperatures and they must be in contact.
Explanation:
For conduction to take place between two objects, they must be in contact with one another and at different temperatures.
Generally, heat transfer takes place over a gradient i.e. from a region of higher temperature to one with a low temperature. If two places or bodies have the same temperature, heat transfer will not take place. In conduction, the two bodies must be in contact with one another. The collision of molecules of one body transfers this kinetic energy to the other one in contact with it.Answer:
The objects must be different temperatures and they must be in contact.
Explanation:
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what the type of solid materials are typically hard, have high melting pionts and poor electrical conductivities
Answer:
Ionic solids
Explanation: Ionic solids—Made up of positive and negative ions and held together by electrostatic attractions. They're characterized by very high melting points and brittleness and are poor conductors in the solid state. An example of an ionic solid is table salt, NaCl.
Answer:
Ionic solids
Explanation:
What is the mass number of this atom ?
How many liters of volume is one mole of gas at standard temperature and
pressure?
22.7 liters
The molar volume of an ideal gas depends on the temperature and pressure. One mole of any ideal gas occupies 22.7 liters at 0 0C and 1 bar (STP).
Hope this helped
1.1
A sample of oxygen occupies 47.2 L under a pressure of 1240 torr at 25 °C. What
volume would it occupy at 25 °C if the pressure were decreased to 730 torr?
Answer:
80.2L
Explanation:
Given parameters:
Initial volume of oxygen = 47.2L
Initial pressure of oxygen = 1240torr
Final pressure = 730torr
Unknown:
Final volume = ?
Solution:
To solve this problem, we apply the Boyle's law proposed by Robert Boyle. It states that "the volume of a fixed mass of a gas varies inversely as the pressure changes if the temperature is constant".
Mathematically;
P₁V₁ = P₂V₂
P and V are pressure and volume
1 and 2 are initial and final states
1240 x 47.2 = 730 x V₂
V₂ = 80.2L
Determine the total number of electrons in the d orbitals of an atom of tin, Sn (Z = 50).
Answer:
Explanation:
Sn (Z = 50 )
Electronic configuration = [Kr] 4d¹⁰5s²5p²
= 1s²2s²p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p²
So , total number of electrons in d orbital = 10 + 10 = 20 .
3. A calibration curve plotting E vs. pNi is used to measure the concentration of Ni2+ in solution at 25 °C using a solid Ni electrode. What is the slope of the calibration curve?
Answer: the slope of the calibration curve is - 0.0295
Explanation:
as things are not under standard conditions that is; 1M of each reactants at T = 25°C and P = 1 atm; therefore we will use the Nernst Equation.
E = a × pNi + b
a is the slope
pNi = -log [Ni²⁺] = log 1/[Ni²⁺]
therefore the Half reaction;
Ni²⁺ (aq) + 2e⁻ = Ni (s)
here; E = E₀ + RT/zF ln[Ni²⁺]
we know that;
gas constant R = (8.31 J/mol-K)
absolute temperature T =25°C = 298 K
number of moles of electrons transferred by the cell's reaction z = 2
F is Faraday constant, = 9.64853399(24)×10⁴ C mol−1
E₀ = b
RT/zF ln[Ni²⁺] = alog 1/[Ni²⁺]
Logx = Ln x / Ln 10 = Ln (x/2.3)
so
a = (RT/zF ln[Ni²⁺])/log 1/[Ni²⁺]
= (RT/zF ln[Ni²⁺]) / ((ln 1/[Ni²⁺]) / 2.3)
= (2.3RT/zF ln[Ni²⁺]) / (ln 1/[Ni²⁺])
= (2.3RT/zF ln[Ni²⁺]) / (-ln [Ni²⁺])
= -2.3RT/zF
so we substitute
= (-2.3 × 8.31 ×298 ) / (2 × 9.64853399(24) × 10⁴)
= - 0.0295
therefore the slope of the calibration curve is - 0.0295
two atoms bonded together will remain some distance apart minimizing the A. Number of valence electrons in the bond. B. Potential energy of the bond. C.partial charge of the bond D.bond distance
Answer:
Answer is the number of the c
Before a chemical reaction, the total mass of two reactants is measured to be 40 grams.
After the reaction, what should be the total mass of the products?
A. 0 grams
B. 20 grams
C. 40 grams
D. 80 grams
The total mass of the products is 40 grams (Option C).
In 1789, Antoine Lavoisier discovered that mass is neither created nor destroyed in chemical reactions. This is now known as Lavoisier's law of conservation of mass. In other terms, the sum of the masses of the reactants is equal to the sum of the masses of the products. So, in this case, the total mass of the products must be 40 grams as well.
The total mass of the products is 40 grams.
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A solution was prepared by mixing 20.00 mL of 0.100 M and 120.00 mL of 0.200 M. Calculate the molarity of the final solution of nitric acid.
Answer:
0.186M
Explanation:
First, we need to obtain the moles of nitric acid that are given for each solution. Then, we need to divide these moles in total volume (120mL + 20mL = 140mL = 0.140L) to obtain molarity:
Moles Nitric acid:
0.0200L * (0.100mol / L) = 0.00200 moles
0.120L * (0.200mol / L)= 0.02400 moles
Total moles: 0.02400moles + 0.00200moles = 0.026 moles of nitric acid
Molarity: 0.026 moles / 0.140L
0.186MIs mass conserved when neutralisation takes place? That is, is the total mass of the acid and alkali equal to the total mass of
the products, salt and water?
Answer:
Yes
Explanation:
yes, this is in every chemical reaction (except nuclear reaction) and Is known as "law of conservation of mass"
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How does heat energy help change shape of metals?
Metals releases heat energy to be able to be shaped.
Heat energy provides more pressure that allows metals to bend.
Heat energy allows metal to become more malleable.
Metals require a lot of heat energy to be destroyed.
Answer: 3
Explanation:
It speed up the molecules to get them to bent and move instead of staying solid
Answer:
c
Explanation:
When enough heat energy is transferred to a metal, the molecules vibrate quickly enough so that the solid metal starts to change shape.
Heptane (C7H16) is a hydrocarbon fuel used for gas barbecues. Balance the chemical equation (given below) for the reaction that occurs when heptane burns in air. What are the coefficients in the balanced equation
Answer:
a = 1, b = 11, c = 7, d = 8
Explanation:
aC7H16 + bO2 ------> cCO2 + dH2O
1 C7H16 + 11 O2 ------> 7 CO2 + 8H2O
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How many electrons are gained in the half-reaction 02 + electrons → 2029
A. 2
B. 1
C. 0
D. 4
Answer:2
Explanation:
He
From which type of clouds do hail pellets form?
Answer:
Hail pallets forms inside of cumulonimbus clouds
Explanation:
Answer: cumulonimbus hope it helps pls stay safe
Calculate the mass percent of 0.389 g of silicon (Si) that reacts with oxygen to form 0.832 g silicon dioxide (SiO 2 )
Answer:
Mass percent of silicon = 46.75% (Approx)
Explanation:
Given:
Mass of silicon = 0.389 g
Mass of silicon dioxide = 0.832 g
Find:
Mass percent of silicon
Computation:
Mass percent of silicon = Mass of silicon / Mass of silicon dioxide
Mass percent of silicon = [0.389 g / 0.832 g]100
Mass percent of silicon = 46.75% (Approx)
If 30.0 g of H2SO4 reacts with sodium hydroxide, what mass of water is produced?
11.02g
Explanation:
mole ratio between H2SO4 and water is 1:2
mole of H2SO4 is 0.306
then the mole of water is 0.612
finally the mole of water is multiplied by 18, the molar mass to get 11.02 g of water
Find the Molarity of 6.25 grams of barium nitrate dissolved in 250 mL solution.
Answer:
0.0956 M
Explanation:
Step 1: Calculate the moles corresponding to 6.25 g of barium nitrate (solute)
The molar mass of barium nitrate is 261.34 g/mol.
6.25 g × 1 mol/261.34 g = 0.0239 mol
Step 2: Convert the volume of solution to liters
We will use the conversion factor 1 L = 1000 mL.
250 mL × 1 L/1000 mL = 0.250 L
Step 3: Calculate the molarity of the solution
The molarity is equal to the moles of solute divided by the liters of solution.
M = 0.0239 mol / 0.250 L = 0.0956 M
What is the cathode in an electrochemical cell?
Answer: The cathode is the electrode where reduction (gain of electrons) takes place (metal-B electrode)
Answer: The electrode where reduction occurs.
How to atoms share more than one pair of electrons?
Answer:
A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.
Explanation:
More than one pair of electrons can be shared between atoms to form double or triple covalent bonds. Unlike ionic bonds, covalent bonds are often formed between atoms where one of the atoms cannot easily attain a noble gas electron shell configuration through the loss or gain of one or two electrons.
A 1.9450 g sample containing only Na2CO3 (F.M. 105.99) and NaHCO3 (F.M. 84.01) is titrated with 35.31 mL of 0.8724 M HCl. Calculate the percentage sodium carbonate and sodium bicarbonate.
Answer:
1.0979g of Na2CO3
0.8471g of NaHCO3
Explanation:
NaHCO3 and Na2CO3 reacts with HCl as follows:
NaHCO3 + HCl → NaCl + H2O + CO2
Na2CO3 + 2HCl → 2NaCl + H2O + CO2
Moles of HCl required were:
0.03531L * (0.8724mol / L) = 0.03080 moles of HCl
With this information we can write 2 equations:
1.9450g = X + Y (1)
X is the mass of NaHCO3 and Y is mass of Na2CO3
Also we can write:
0.03080 moles = X/84 + 2Y/106 (2)
Where 84 is molar mass of NaHCO3 and 106 is molar mass of Na2CO3, 2 is due the reaction (2 moles of HCl react per mole of Na2CO3)
Replacing (1) in (2):
0.03080 moles = (1.9450-Y)/84 + 2Y/106
0.03080 = 0.023155 - Y/84 + Y/53
0.007645 = 0.00696316Y
Y = 1.0979g of Na2CO3
And mass of NaHCO3 =
1.9450g - 1.0979g =
0.8471g of NaHCO3
Which term describes boron?
A. Metal
B. Metalloid
C. Noble Gas
D. Nonmetal
Answer:
Boron is Nonmetal
Explanation:
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A flask of ammonia is connected to a flask of an unknown acid HX by a 1.68 m glass tube (where "X" represents a halogen). As the two gases diffuse down the tube, a white ring of NH4X forms 115 cm from the ammonia flask. Identify element X (Name or symbol).
Answer:
Explanation:
white ring of NH₄X is formed . Here X is Cl and
NH₄X is NH₄Cl ( ammonium chloride )
The reaction is as follows
NH₃ + HCl = NH₄Cl ( white fume )
The acid that reacts with ammonia has been Hydrochloric acid (HCl), and the element X in the acid has been Chlorine (Cl).
The ammonia has been the gas with the pungent smell. It has been the compound with the dihybrid element used for the production of various nitrogen compounds.
The reaction of Ammonia with acid results in the formation of ammonium ions. The ions on reacting with the basic part of the acid, form the salt and give the product.
The white ring with the reaction of ammonia has been formed of the ammonium chloride. Thus the acid that reacts with ammonia has been Hydrochloric acid (HCl), and the element X in the acid has been Chlorine (Cl).
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