Answer:
C- 0.25mol/L
Explanation:
Hcl+Naoh-Nacl+H2O
Ratio =1:1
0.2moles of Naoh in1000cm3 what about 25=(25×0.2)÷1000=
0.005moles
0.005moles in 20cm³ what about in 1000
(0.005×1000)÷20=0.25mol/L
According to the molar concentration, the concentration of the acid is 2.5 mole/liters.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.In case of 2 solutions, molar concentration is obtained as M₁V₁=M₂V₂, on substitution of values, M₁=25×0.20/20=2.5 mole/L.
Thus,the concentration of the acid is 2.5 mole/liters.
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This is how osmium appears in the periodic table.A purple box has O s at the center and 76 above. Below it says osmium and below that 190.23.
Rounded to the nearest whole number, how many neutrons, on average, are in an atom of osmium?
a76
b114
c 190
d266
Answer:
114
Explanation:
plz make me brainiest
An elements mass number is made up of the number of ____ in the nucleus.
protons and neutrons
electrons and neutrons
protons and electrons
atoms and molecules
Answer:
The answer is protons and nuetrons
Explanation:
Photosynthesis produces (4 points)
carbon dioxide and energy
carbon dioxide and oxygen
glucose and oxygen
glucose and carbon dioxide
(I'm pretty positive it's C, but correct me if I'm wrong)
Answer:
Glucose and oxygen is produced during photosyntheis
Explanation:
Carbon dioxide and water are required for photosyntheis producing oxygen and glucose
Answer:
C.Glucose and oxygen
9.0 L of a gas at 25 oC expands to a volume of 25.0 L. What is the resulting temperature in Kelvin?
Answer:
Explanation:
H
Which statement describes a process involved in the evolution of Earth’s early atmosphere?
A.
Cyanobacteria transformed carbon dioxide in the atmosphere into oxygen during photosynthesis.
B.
Heavier gases escaped through Earth’s atmosphere, leaving only lighter gases such as oxygen behind.
C.
Volcanic eruptions produced enough oxygen to create Earth’s atmosphere.
D.
The amount of oxygen in the atmosphere declined due to respiration, or breathing.A sea breeze is a wind that blows from the sea toward land. Which statement best explains how air pressure influences sea breezes?
A.
Wind always blows from the sea toward land, regardless of differences in air pressure.
B.
The air above the land has a lower pressure than the air above the sea.
C.
The air above the sea has a lower pressure than the air above the land.
D.
The sea and the land are at equivalent air pressures, so waves cause the wind to move toward the land.
Answer:
D
Explanation:
Which substances are products of a fermentation reaction?
1.water and carbon dioxide
2.alcohol and carbon dioxide
3.soap and glycerol
4.ester and water
Answer:
2.alcohol and carbon dioxide
Explanation:
Fermentation is a metabolic process which is used to produce chemical changes in various organic substances. This process is used in many fields including biochemistry, where it is defined as the "extraction of energy from carbohydrates in the absence of oxygen". The main substances produced from fermentation reaction are alcohol, carbon dioxide and lactic acid.
Lulu Labwrecker carefully pipets 25.0 mL of 0.525 M NaOH into a test tube. She places the test tube into a small beaker to keep it from spilling and then pipets 75.0 mL of 0.355 M HCl into another test tube. When Lulu reaches to put this test tube of acid into the beaker along with test tube of base she accidentally knocks the test tubes together hard enough to break them and their respective contents combine in the bottom of the beaker. Is the solution formed from the contents of the two test tubes acidic or basic? What is the pH of the resulting solution?
Answer:
The solution formed is acidic
pH = 0.87
Explanation:
The acid-base reaction of NaOH with HCl is:
NaOH + HCl → NaCl + H₂O
Where 1 mole of NaOH reacts with 1 mole of HCl
In the problem, moles of NaOH and HCl are:
NaOH: 0.0250L × (0.525mol / L) = 0.013125 moles NaOH
HCl: 0.0750 × (0.355mol / L) = 0.026625 moles HCl
As moles of HCl > moles NaOH, HCl is in excess and the solution formed is acidic
Moles in excess of HCl are:
0.026625 moles - 0.013125 moles = 0.0135 moles HCl
As the volume of the solutions is 25.0mL + 75.0mL = 100.0mL = 0.100L, molarity of HCl after reaction is:
0.0135 moles HCl / 0.100L = 0.135M HCl = 0.135M H⁺
As pH is defined as - log [H⁺], pH of the solution is:
pH = -log 0.135M H⁺ = 0.87
pH = 0.87
The pH of the resulting solution of the acid and base mixture is; Acidic with a PH = 0.87
We are given;
Volume of NaOH = 25 mL = 0.025 L
Volume of HCl = 75 mL = 0.075 L
Concentration of NaOH = 0.525 M
Concentration of HCl = 0.355 M
Total volume of solution = 0.025 + 0.075 = 0.1 L
Now, the the equation of the reaction is;
HCl + NaOH = NaCl + H2O
We can see that 1 mole of HCl reacts with 1 mole of NaOH.
Since; number of moles = Volume × concentration
Number of moles of HCl = 0.075 × 0.355
Number of moles of HCl = 0.026625 moles
Similarly;
Number of moles of NaOH = 0.025 × 0.525
Number of moles of NaOH = 0.013125 moles
We can see that the number of moles of HCl is greater than that of NaOH and as such there is excess HCl acid in the mix.
Thus,
Excess moles of HCl acid = 0.026625 - 0.013125
Excess moles of HCl acid = 0.0135 moles
Concentration of this excess HCl is gotten by the formula;
M = Excess moles/total volume
M = 0.0135/0.1
M = 0.135 M
PH of this excess concentration is;
PH = -log [H+]
PH = -log [0.135]
PH = 0.87
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can a substance be a lewis acid without being a bronsted-lowry acid?argue
Answer:
Yes
Explanation:
Yes, A substance can be a lewis acid without being a Bronsted-Lowery acid because there are some substances which cannot donate protons(Bronsted-Lowery acid) but can accept a pair of electron.
For Example:
Let us take the example of BF₃
BF₃ contains no proton so it is not a Bronsted Lowery Acid
However, BF₃ has an incomplete octet with 6 electrons. It needs an electron pair to complete its octet. It accepts a pair of electron to become a Lewis Acid
Answer:
Interesting question, and the answer is yes, a substance can be a Lewis acid but not a Bronsted-Lowrey acid. To see this, let’s take a look at the definitions of each.
Explanation:
Bronsted-Lowrey acid:
A compound that is a hydrogen ion (proton) donor. When dissolved in the solvent in question, these compounds lose a proton to the solution. The concentration of these protons in solution is referred to as acidity, and is measured on the pH scale.
Lewis acid:
A substance that is an electron pair receiver. In solution, free electron pairs will form bonds with the substance, either ionic or covalent. In this definition, a proton is itself an acid, rather than a part of an acid.
A key thing to note here is that, in the Bronsted-Lowrey definition, there must be a proton. That means, all Bronsted-Lowrey acids are of the form HXn→H++Xn− , showing the dissociation in solution. However, a Lewis acid needs only to have the ability to accept an electron pair, which means that H+ is a Lewis acid, instead of what makes a compound an acid. Additionally, that means that the number of compounds that qualify as a Lewis acid are expanded. A favorite example of mine is boron trifluoride, or BF3 . It is a common reagent in organic synthesis, it is a Lewis acid, but does not have any hydrogen, so it cannot be a Bronsted-Lowrey acid
how can you tell from the name the types of bonds present in a hydrocarbon?
Answer:
Alkane
Alkene
Alkyne
Explanation:
Alkane=1 bond (Saturated hydrocarbon)
Alkene= 2 bonds (Unsaturated hydrocarbon)
Alkyne= triple bonds (Unsaturated hydrocarbon)
Formula of Alkane = CnH2n+2
Formula of Alkene = CnH2n
Formula of Alkyne = CnH2n-2
Why does the ionization energy change when moving down a group of elements?
The number of valence electrons increases.
The nuclear positive charge increases.
The energy levels are increasing.
The attractive force decreases as the atom gets larger.
Answer:
D) The attractive force decreases as the atom gets larger.
Explanation:
i did the lesson and tried all 3, all 3 times, this was the last one and only choice left so it has to be.
Answer:
The attractive force decreases as the atom gets larger.
Explanation:
How marly electrons are in an atom of elemental
sodium?
Answer: 11 Electrons
Explanation:
We know that the atomic number of sodium is 11. This tells us that sodium has 11 protons and because it is neutral it has 11 electrons.
Answer:
The sodium atom is left with a full outermost electron shell with eight electrons, and the outermost shell of the other atom is full as well.
Explanation:
The sodium atom now has a positive electrical charge of plus 1, and the other atom has a negative charge of minus 1. The two opposite charges attract, and the two atoms now form the molecule of a compound.
I NEED HELP PLEASE, THANKS! :)
The mole is a counting number that allows scientists to describe how individual molecules and atoms react. If one mole of atoms or molecules is equal to 6.022 × 10^23 atoms or molecules, how many molecules are in a 23.45 g sample of copper (II) hydroxide, Cu(OH)2? Express your answer to the correct number of significant figures. (MM of Cu(OH)2 is 97.562 g/mol)
Answer:
[tex]\large \boxed{1.447 \times 10^{23}\text{ molecules Cu(OH)}_{2 }}[/tex]
Explanation:
1. Calculate the moles of copper(II) hydroxide
[tex]\text{Moles of Cu(OH)}_{2} = \text{23.45 g Cu(OH)}_{2} \times \dfrac{\text{1 mol Cu(OH)}_{2}}{\text{97.562 g Cu(OH)}_{2}} = \\\\\text{0.240 36 mol Cu(OH)}_{2}[/tex]
2. Calculate the molecules of copper(II) hydroxide
[tex]\text{No. of molecules} = \text{0.240 36 mol Cu(OH)}_{2} \times \dfrac{6.022 \times 10^{23}\text{ molecules Cu(OH)}_{2}}{\text{1 mol Cu(OH)}_{2}}\\\\= 1.447 \times 10^{23}\text{ molecules Cu(OH)}_{2}\\\text{The sample contains $\large \boxed{\mathbf{1.447 \times 10^{23}}\textbf{ molecules Cu(OH)}_{\mathbf{2}}}$}[/tex]
Answer:
Mass of Cu(OH)2 = 23.45 g
Molar mass of Cu(OH)2 = 97.562 g/mol
Since we know,
Moles = Mass/Molar mass
\Rightarrow Moles = (23.45 g)/(97.562 g/mol) = 0.2404 moles
Since 1 mole of substance contains = 6.022 × 1023 molecules
So 0.2404 moles will contain = 0.2404*(6.022 × 1023 molecules) = 1.448 × 1023 molecules
Explanation:
What is a chemical solution and what are the names of its components?
Answer:
A chemical solution is defined as a homogeneous mixture of two or more substances. There are two components of chemical solution that include solute and solvent.
Solute is the component that get dissolved in another substance and solvent is the substance that dissolve solute.
For example: carbon dioxide in water. Where carbon-dioxide is solute and water is solvent.
A weather balloon calibrated at 0.00 °C to have a volume of 20.0 L has
what volume at -40.0 °C assuming pressure is held constant?
Answer:
17.1 Liters
Explanation:
It's a gas law question (more specifically a Charles's Law question). Formula is V1/T1 = V2/T2. You're given V1 and T1 and T2. However, in order to use the equation, temperature needs to be in Kelvins (by subtracting the degrees C from 273) for the numbers to work (among other reasons, the 0 degrees C will always give you an answer of zero or undefined). Placing all temps in kelvins makes the answers come out right. So 20L/273K = xL/233K gives you the answer when you cross-multiply.
Considering the Charles's law, a weather balloon calibrated at 0.00 °C to have a volume of 20.0 L has 17.07 L at -40.0 °C, assuming pressure is held constant.
The gas laws are a set of chemical and physical laws that allow determining the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature and moles.
Charles's law is one of the gas laws. It relates the volume and the temperature of a certain quantity of ideal gas, kept at a constant pressure.
This law states that, at constant pressure, the volume of a gas is directly proportional to its temperature. In other words, for a given sum of gas at constant pressure, as the temperature increases, the volume of the gas increases, and as the temperature decreases, the volume of the gas decreases.
Mathematically, Charles's law says that the quotient that exists between the volume and the temperature will always have the same value:
[tex]\frac{V}{T}=k[/tex]
Being an initial state 1 and a final state 2, it is true:
[tex]\frac{V1}{T1}=\frac{V2}{T2}[/tex]
In this case, you know:
V1= 20 LT1= 0 C=273 KV2= ?T2= -40 C= 233 KReplacing:
[tex]\frac{20 L}{273 K}=\frac{V2}{233 K}[/tex]
Solving:
[tex]V2=233 K x\frac{20 L}{273 K}[/tex]
V2=17.07 L
Finally, a weather balloon calibrated at 0.00 °C to have a volume of 20.0 L has 17.07 L at -40.0 °C, assuming pressure is held constant.
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https://brainly.com/question/4147359?referrer=searchResultsWhich statement best compares the energy involved in melting with the energy involved in boiling for a given liquid?
Answer: Energy is removed from the particles in each change, but more energy is removed in melting than in boiling because the attractions are weaker. Energy is removed from the particles in each change, but more energy is removed in boiling than in melting because the attractions are weaker. Energy is added to the particles in each change, but boiling requires more energy than melting because the attractions must be completely overcome. Energy is added to the particles in each change, but melting requires more energy than boiling because the attractions must be completely overcome.
Reply ASAP: Why do electrons affect the structure of a molecule?
A. Bonding pairs are positively charged and lone pairs are negatively charged and they push each other into certain shapes.
B. They do not.
C. The electron clouds are negatively charged and repel each other as far apart as possible.
D. Bonding pairs are negatively charged and lone pairs are positively charged and they push each other into certain shapes.
Answer:
C. The electron clouds are negatively charged and repel each other as far apart as possible
Explanation:
This is the basis of VSEPR theory.
The angles between the electron clouds determine the shapes of the molecules.
B. and D. are wrong. All electron pairs are negatively charged.
The electrons affect the structure of a molecule because the bonding pairs are positively charged and lone pairs are negatively charged and they push each other into certain shapes.
What is the shape of an atom?Every atom or molecule consist some kind of geometry or shapes like linier, tetrahedral, square planner, octahedral etc. with some bond length and angles present with them.
The bond pairs in a geometry is made up with positive charge and lone pairs present on the atom in the form of negative charge as they both are opposite in nature and repel or push each other in opposite direction.
Due to this phenomena the structure of the atom gets effected and geometry will change on the basis of lone pair and bond pair repulsion.
Therefore, electrons affect the structure of a molecule because the bonding pairs are positively charged and lone pairs are negatively charged and they push each other into certain shapes.
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the kidneys in human beings are a part of the system for
(c)
Suggest a reason why substance E does not conduct electricity in both solid and
molten states.
Answer:
Substance E does not conduct electricity in both solid and molten states because of very low melting and boiling points.
In both solid and molten state free electrons are required to conduct electricity. substance E has low boiling and melting point which means substance will have relatively weak bonds. Because of weak bonds substance E might not have much free electron in its outermost shell that can cause the electric current by their coordinated movement.
Hence, substance E is unable to conduct in both melting and molten state.
You have nitrogen gas (N2) at a pressure of 0.5 atm, a volume of 25000 mL, and a temperature of 300 K, how many grams of nitrogen are present?
Answer:
About 7.109g
Explanation:
25000mL is the same as 25 liters.
[tex]PV=nRT \\\\0.5 (25)=n (0.0821) (300) \\\\n\approx 0.508[/tex]
Multiplying this by the molar mass of nitrogen, you get about 7.109 grams of nitrogen. Hope this helps!
Where do you find the molar mass of an element
Answer:
Mass of a given chemical element or compound divided by the amount of substance.
(g/mol)
What is solid carbon dioxide oxide
Answer:
dry ice
Explanation:
hope this helps
:)
Answer:
Dry Ice is the common name for solid carbon dioxide (CO2). It gets this name because it does not melt into a liquid when heated; instead, it changes directly into a gas (a process known as sublimation).
Explanation:
The name given to the substance formed when a liquid is miscible in another liquid.
Answer:
Solute
Explanation:
a student balanced the chemical equation for the reaction of magnesium with oxygen by writing Mg + O2 ----> MgO2. What is wrong with this equation?
Answer:
Explanation:
Magnesium when it oxidizes has a valence of 2.
Oxygen, when it mixes with something, has a valence of - 2
So Mg and O2 will form something, but what? The answer is MgO
Mg + O2 ===> MgO
To balance this equation, you need 2 Magnesiums on the right and 2 Oxygens also on the right. The left will need a two Magnesiums.
The balanced equation will be
2Mg + O2 ====> 2MgO
C2H5OH(l)+CH3COOH(l) → CH3COOC2H5(l)+H2O(l) If the yield of ethyl ethanoate obtained when 20.00 g of ethanol is reacted with excess ethanoic acid is 30.27 g, calculate the percentage yield
Answer:
The percentage yield is 79.12%
Explanation:
The first thing we need to calculate here is the theoretical yield of ethyl ethanoate that can be obtained from 20g of ethanol.
Since the mole ratio is 1:1, then this is quite straightforward.
What we need to obtain at first here is the number of theoretical moles of ethanol reacting.
That would be mass of ethanol/molar mass of ethanol
Molar mass of ethanol is 46g/mol
Thus the number of moles is 20/46 = 0.4348 mole
Like it is indicated earlier, since the number of moles are equal from the balanced equation, it also means that 0.4348 mole of ethylethanoate is produced
Now, we need to know the mass of ethyl ethanoate produced
The mass can be calculated by multiplying the number of moles by the molar mass
The molar mass of ethyl ethanoate is 88g/mol
So the mass of it produced = 0.4348 * 88 = 38.2624 or let’s just say 38.26
Thus, the percentage yield will be;
Actual yield/Theoretical yield * 100%
From the question, our actual yield is 30.27g while our calculated theoretical yield is 38.26g
= 30.27/38.26 * 100% = 79.12%
The forces between water molecules are stronger
than the forces between ethanol molecules. Which
liquid would probably be most difficult for an insect
to walk on? Explain your answer.
Answer:
An insect would have an easier time walking on the surface of water than on the surface of ethanol.
Water's stronger intermolecular forces lead to higher surface tension.
Higher surface tension allows water to support the insect.
Answer:
An insect would have an easier time walking on the surface of water than on the surface of ethanol.
Water's stronger intermolecular forces lead to higher surface tension.
Higher surface tension allows water to support the insect.
Explanation:
Calcium carbonate, when heated, forms calcium oxide and carbon dioxide. 100grams of calcium carbonate will produce 56grams of calcium oxide. How many grams of carbon dioxide will it produce? Show working out
Answer:
It will produce 44 grams of carbon dioxide
Explanation:
Step 1: Data given
MAss of CaCO3 = 100 grams
Molar mass of CaCO3 = 100.09 g/mol
Mass of CaO produced = 56 grams
Molar mass of CaO = 56.08 g/mol
Step 2: The balanced equation
CaCO3 → CaO + CO2
Step 3: Calculate moles CaCO3
Moles CaCO3 = mass CaCO3 / molar mass CaCO3
Moles CaCO3 = 100 grams / 100.09 g/mol
Moles CaCO3 = 1.00 moles
Step 4: Calculate moles CaO
Moles CaO = 56 grams / 56.08 g/mol
Moles CaO = 1.00 moles
Step 5: Calculate moles CO2
For 1 mol CaCO3 we'll have 1 mol 1 mol CaO and 1 mol CO2
Step 6: Calculate mass CO2
Mass CO2 = moles CO2 * molar mass CO2
Mass CO2 = 1.00 moles * 44.0 g/mol
Mass CO2 = 44 grams
It will produce 44 grams of carbon dioxide
A 2.575 g piece of gold (specific heat = 0.129 J/g°C) at a temperature of 75°C is placed into cold water at 10°C. If the gold loses 10.0 J of energy, what is its final
temperature in the water? Enter your answer to the
nearest whole number of °C.
Answer:
The final temperature of the mixture is 44.9°C
Explanation:
Mass of the substance (gold) = 2.575g
Specific heat capacity of gold = 0.129J/g°C
Initial temperature (T1) = 75°C
Final temperature (T2) = ?
Energy lost = 10J
Heat energy(Q) = MC∇T
Q = heat energy (in this case lost)
M = mass of the substance
C = specific heat capacity of the substance
∇T = change in temperature of the substance = (T2 - T1)
Q = MC∇T
Q = MC(T2 - T1)
-10 = 2.575 × 0.129 × (T2 - 75) energy is -ve because it was energy lost.
-10 = 0.3321 × (T2 - 75)
-10 = 0.3321T2 - 24.9075
Collect like terms
0.3321T2 = 24.9075 - 10
0.3321T2 = 14.9075
T2 = 14.9075 / 0.3321
T2 = 44.88
T2 = 44.9°C
The final temperature of the mixture is 44.9°C
Which elements are diatomic?
Answer:The elements hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine and iodine are diatomic elements
Definition of diatomic elements:Diatomic elements are special as the atoms that form it do not like to be alone. That is, you will never find a nitrogen or fluorine atom, for example, hanging out solo. Rather, these atoms will always be paired together because they need to pool resources to have enough electrons.
Answer:
H2, O2, N2, F2, Cl2, Br2, I2
Explanation:
These occur naturally has molecules of 2 atoms.
They are all gases except Br2, liquid and iodine which is solid.
which of these methods could are used to separate an insoluble solid and soluble solid
Answer:
To separate an insoluble solid from a soluble solid: Mixing the mixture with water, filtering out the insoluble solid, and then evaporating the water to isolate the soluble solid.
Explanation:
How will you test for the gas which is liberated when hcl reacts with an active metal ?