Answer:
A
Explanation:
We are given that the molar mass of boron triflouride BF₃ is 67.81 g/mol. We want to determine the number of molecules of BF₃ in 2 g of BF₃.
Recall that there are 6.02 × 10²³ molecules in any mole of a substance. In other words, there are 6.02 × 10²³ BF₃ molecules in a mole of BF₃. Starting with the initial value, multiply:
[tex]\displaystyle \begin{aligned} 2\text{ g BF$_3$}&\cdot \frac{1\text{ mol BF$_3$}}{67.81 \text{ g BF$_3$}} \cdot \frac{6.02\times 10^{23} \text{ molecules BF$_3$}}{1 \text{ mol BF$_3$}} \\ \\ &= 1.776 \times 10^{22} \text{ molecules BF$_3$}\end{aligned}[/tex]
Hence, our answer is A.
*Perhaps it rendered the values incorrectly, but since we started with only 2 g of BF₃, our resulting calculation should only contain one significant digit. Hence, the correct answer should be 2 × 10²² molecules of BF₃.
The molecules of BF₃ that are there in 2 g is 1.776 × 10²² molecules and the correct option is option A.
The mole is an amount unit similar to familiar units like pair, dozen, gross, etc. It provides a specific measure of the number of atoms or molecules in a bulk sample of matter.
A mole is defined as the amount of substance containing the same number of atoms, molecules, ions, etc. as the number of atoms in a sample of pure 12C weighing exactly 12 g.
Given,
Molar mass of BF₃ = 67.81 g/mol
Mass = 2g
Moles = mass / molar mass
= 2 / 67.81
= 0.029 moles
1 mole = 6.023 × 10²³
0.029 moles = 6.023 × 10²³ × 0.029
= 1.776 × 10²² molecules
Thus, the ideal selection is option A.
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How many grams of NaOH is needed to neutralize 90 mL of 1.5 N HCl?
mol = conc × v
= 1.5 × 0.09
= 0.135 moles of HCl
HCl + NaOH > NaCl + H2O
1 mole HCl = 1 mole NaOH
0.135 mol HCl = x
x = 0.135 mol NaOH
mass = mol × molar mass
= 0.135 × 40
= 5.4 g
NaOH = 23 + 16 + 1 = 40 g/mol
I'm not a 100% sure if it's correct
Which of the compounds, C4H10, BaSO4, Zn(CN)2, Al(OH)3, contain an anion with a -1 charge?
Answer:
b
Explanation:
OH and CN both have -1 charges
What volume of 0.826 MKOH solution do you need to make 3.74 L of a solution with a pH of 12.500?
Given that –
pH = 12.5We know that –
pH + pOH = 14Then –
[tex]\qquad[/tex][tex]\bf\longrightarrow pOH = 14 -12.5 [/tex]
[tex]\qquad[/tex][tex]\sf \longrightarrow pOH = 1.5[/tex]
[tex]\qquad[/tex][tex]\sf \longrightarrow [OH^- ] = 10^{-1.5 }[/tex]
[tex]\qquad[/tex][tex]\bf \longrightarrow [OH^-] = 3.16 × 10^{-2}[/tex]
Now the number of moles of KOH need to ensure that concentration of Hydroxide anions is equal to –
[tex]\qquad[/tex][tex]\bf \longrightarrow 3.74\: L \times \dfrac{3.16× 10^{-2}}{1 \: L }[/tex]
[tex]\qquad[/tex][tex]\bf \longrightarrow 1. 18 × 10^{-1 }M [/tex]
Volume of the solution contains the need number of moles of Hydroxide anions –
[tex]\qquad[/tex][tex]\sf \longrightarrow \dfrac{ 1.18×10^{-1} \: moles \: OH^-}{0.826 \: moles \: OH^-}[/tex]
[tex]\qquad[/tex][tex]\sf \longrightarrow 0.143 L [/tex]
[tex]\qquad[/tex][tex]\sf \longrightarrow 0.143 \times 1000[/tex]
[tex]\qquad[/tex][tex]\pink{\bf\longrightarrow 143 mL }[/tex]
______________________________________
. What mass of ammonium chloride must be added to 250. mL of water to give a solution with pH
4.85? [Kb(NH3) = 1.8 x 10-1
a. 4.7 g
b. 75 g
c.2.3 x 10-ºg
d. 19 g
e.10g
The mass of ammonium chloride that must be added is : ( A ) 4.7 g
Given data :
Volume of water ( V ) = 250 mL = 0.25 L
pH of solution = 4.85
Kb = 1.8 * 10⁻⁵
Kw = 10⁻¹⁴
Given that the dissolution of NH₄Cl gives NH₄⁺⁺ and Cl⁻ ions the equation is written as :
NH₄CI + H₂O ⇄ NH₃ + H₃O⁺
where conc of H₃O⁺
[ H₃O⁺ ] = [tex]\sqrt{Ka.C}[/tex] and Ka = Kw / Kb
∴ Ka = 5.56 * 10⁻¹⁰
Next step : Determine the concentration of H₃O⁺ in the solution
pH = - log [ H₃O⁺ ] = 4.85
∴ [ H₃O⁺ ] in the solution = 1.14125 * 10⁻⁵
Next step : Determine the concentration of NH₄CI in the solution
C = [ H₃O⁺ ]² / Ka
= ( 1.14125 * 10⁻⁵ )² / 5.56 * 10⁻¹⁰
= 0.359 mol / L
Determine the number of moles of NH₄CI in the solution
n = C . V
= 0.359 mol / L * 0.25 L = 0.08979 mole
Final step : determine the mass of ammonium chloride that must be added to 250 mL
mass = n * molar mass
= 0.08979 * 53.5 g/mol
= 4.80 g ≈ 4.7 grams
Therefore we can conclude that the mass of ammonium chloride that must be added is 4.7 g
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how many molecule are there in 24.0 L of oxygen gas at standard temperature and pressure
There are 6.44 × 10²³ molecules in 24.0 L of oxygen gas at standard temperature and pressure.
HOW TO CALCULATE NUMBER OF MOLECULES:
To calculate the number of molecules in a substance, we need the number of moles. The number of moles can be calculated using ideal gas law equation as follows:
PV = nRT
Where;
P = pressureV = volumen = number of molesT = temperatureR = gas law constantAccording to this question, oxygen gas is at standard temperature (273K) and pressure (1 atm)
1 × 24 = n × 0.0821 × 273
24 = 22.4n
n = 24 ÷ 22.4
n = 1.07moles
To calculate the number of molecules, we multiply the no. of moles by Avogadro's number (6.02 × 10²³)
no. of molecules = 1.07 × 6.02 × 10²³
no. of molecules = 6.44 × 10²³
Therefore, there are 6.44 × 10²³ molecules in 24.0 L of oxygen gas at standard temperature and pressure.
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Calculate the mass percentage of each element in aluminum oxide.
Answer:
So, Percentage Composition of Aluminium = 2778×100%=34.62% (approx.) Percentage Composition of Oxygen = 3×1678×100%=61.54% (approx.)
Select True or False: Consider the reaction N2(g) 3H2(g) 2NH3(g). The production of ammonia is an exothermic reaction. When heat is added to the equilibrium system it will shift to increase the amount of ammonia produced.
Answer:
False
Explanation:
As I like to think of it, equilibrium will shift either 'forwards' (to increase products) or 'backwards' (to increase reactants) to oppose any change in system;
If heat is added, the equilibrium will shift in the direction that reduces heat within the system;
In other words, it will shift in favour of the endothermic reaction, i.e. the reaction where heat is gained by the molecules/atoms and therefore taken out from the system;
If the 'forwards' reaction, producing NH₃, is exothermic (i.e. energy is released in the reaction), then the 'backwards' reaction is endothermic;
So the equilibrium will shift in this direction, which is the reaction of 2 NH₃ molecules producing N₂ and 3 H₂
Will the following replacement reaction occur? MgCl2 + I2 → ?
Yes, it will because chlorine is less reactive than iodine.
No, it will not because iodine is less reactive than chlorine.
No, it will not because iodine and chlorine will not bond.
Yes, it will because the iodine will replace the magnesium.
The replacement reaction will not occur because iodine is less reactive than chlorine.
REPLACEMENT REACTION:A replacement reaction is a type of reaction in which one element is replaced by another in a compound.
The principle behind one element replacing the other is based on the reactivity of an element. A more reactive element will displace a less reactive one.
According to this question, the following displacement reaction is given: MgCl2 + I2 → ?
This reaction will not occur because chlorine is more reactive/electronegative than iodine, hence, iodine cannot displace it.
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Fe3+ and S2- write the formula for the compound that would be formed
PLEASE HELP WILL GIVE BRAINLIEST
Answer:
Explanation:
Gravity pulls the balls down the ramp, and the force of gravity is bigger on larger-mass objects. The extra force on the bigger ball means that it has more energy when it gets to the bottom of the ramp and consequently travels more before stopping.
A student was asked to determine the concentration of ammonia, a volatile substance used in the clinical setting as a respiretory stimulant to prevent fainting. First the student pipetted 25.00 mL of the cloudy ammonia solution into a 250.0 mL conical flask. 50.00 mL of 0.100 mol L' HCl(aq) was immediately added to the conical flask which reacted with the ammonia in solution. The excess (unreacted) HCI was then titrated with 0.050 mol L- Na2CO3(aq). 21.50 mL of Na2CO3(aq) was required. Calculate the concentration of the ammonia in the cloudy ammonia solution.
This question is describing two chemical equations whereby the concentration of ammonia has to be determined. The first reaction is between 25.00 mL of ammonia and 50.00 mL of 0.100-M HCl whose excess was neutralized with 21.50 mL of 0.050-M Na₂CO₃ and thus, the concentration ammonia in the cloudy solution was determined as 0.114 M.
First of all we need to go over the titration of the excess HCl with Na₂CO₃ by writing the chemical equation it takes place when they react:
[tex]2HCl+Na_2CO_3\rightarrow 2NaCl+CO_2+H_2O[/tex]
Whereas the mole ratio of HCl to Na₂CO₃ is 2:1 and the volume of the HCl leftover is determined as follows:
[tex]V_{HCl}^{leftover}=\frac{2*0.050M*21.50mL}{0.100M} =21.5mL[/tex]
Next, we infer that the consumed volume of HCl by the ammonia solution was:
[tex]V_{HCl}^{consumed}=50.00mL-21.50mL=28.5 mL[/tex]
Then, we write the chemical equation that takes place between ammonia and HCl:
[tex]HCl+NH_3\rightarrow NH_4Cl[/tex]
Whereas the mole ratio is now 1:1, which means that the concentration of ammonia was:
[tex]M_{NH_3}=\frac{28.5mL*0.100M}{25.00mL}\\\\ M_{NH_3}=0.114M[/tex]
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(Titration) https://brainly.com/question/15687419(Titration) https://brainly.com/question/25328286the weak base ionization constant (ka) for h2c2o4 is equal to what?
The acid ionization constant is the quantitative measure of the acidic strength. For oxalic acid, Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]
What is acid dissociation?Acid dissociation (Ka) is the ratio of the concentration of the conjugate base and hydrogen ion to the concentration of the chemical.
Oxalic acid is a weak acid and gets dissociated as:
H₂C₂O₄ ⇌ H⁺ + HC₂O₄⁻
or
HC₂O₄⁻ ⇌ H⁺ + C₂O₄²⁻
The acid ionization constant for the reactant and the product is given as:
Ka = [H⁺] [A⁻] / [HA]
Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]
Therefore, the ionization constant for oxalic acid is given as Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]
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Alguien saber esto? Literal no se este material
Answer:
2. 389.15K , 3. 229.15K
Explanation:
K-273.15 = °C
Consider the chemical formula for calcium chlorate: Ca(ClO3)2
How many of each of these atoms is in a molecule of calcium chlorate?
I hope it help u =)
Brainliest answer pls
Need ASAP will give brainlist
Answer:
A.
The answer is A :)
According to Dalton's atomic theory, atoms
a: of different elements combine in simple whole-number ratios to form compounds
b: can be divided into protons, neutrons, and electrons
c: of all elements are identical in size and mass
d: can be destroyed in chemical reactions
According to Dalton's atomic theory, atoms of different elements combine in simple whole-number ratios to form compounds.
DALTON'S ATOMIC THEORY:As the name implies, Dalton's atomic theory is a theory proposed by an English scientist named John Dalton in the 1900's.
The Dalton's atomic theory is composed of five main parts, which are as follows:
All matter is comprised of tiny, definite particles called atoms.Atoms are indivisible and cannot be destroyed.All atoms of a particular element are identical in size and weight.Atoms of different elements contain different mass.Atoms of different elements combine in fixed whole-number ratios when forming compounds.Therefore, in accordance to Dalton's atomic theory, atoms of different elements combine in simple whole-number ratios to form compounds.
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what is science explain
Science can be defined as the study of nature, its behaviors and the
interactions between the various components.
Science is divided into three main branches which are
PhysicsChemistryBiologyScience can also be referred to as the gaining of knowledge through various
methods and verifiable by experiments to ensure it is valid.
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2 FeCl2
+ 13 KClO4
+ H2
SO4
→ 2 Fe(ClO3
)3
+
K2
SO4
+ 11 KClO3
+ H2
O
Calculate the grams of KClO3
arising from the
reaction of 2.50 g of KClO4
with 150 mg of FeCl2
in excess of H2
SO4
.
Taking into account the reaction stoichiometry and limiting reagent, 0.7977 grams of KClO₃ are formed from the reaction of 2.50 g of KClO₄ with 150 mg of FeCl₂ in excess of H₂SO₄.
In first place, the balanced reaction is:
2 FeCl₂ + 13 KClO₄ + H₂SO₄ → 2 Fe(ClO₃)₃ + K₂SO₄ + 11 KClO₃ + H₂O
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
FeCl₂: 2 molesKClO₄: 13 moles H₂SO₄: 1 moleFe(ClO₃)₃: 2 moles K₂SO₄: 1 mole KClO₃: 11 moles H₂O: 1 moleThe molar mass of the compounds is:
FeCl₂: 126.75 g/moleKClO₄: 138.55 g/mole H₂SO₄: 98 g/moleFe(ClO₃)₃: 306.2 g/moleK₂SO₄: 174.2 g/moleKClO₃: 122.55 g/moleH₂O: 18 g/moleThen, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
FeCl₂: 2 moles× 126.75 g/mole= 253.5 gramsKClO₄: 13 moles× 138.55 g/mol= 1801.15 grams H₂SO₄: 1 mole× 98 g/mole= 98 gramsFe(ClO₃)₃: 2 moles× 306.2 g/mole= 612.4 gramsK₂SO₄: 1 mole× 174.2 g/mole= 174.2 gramsKClO₃: 11 moles× 122.55 g/mole= 1348.05 gramsH₂O: 1 mole× 18 g/mole= 18 grams
The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.
To determine the limiting reagent, it is possible to use the reaction stoichiometry of the reaction and a simple rule of three as follows: if by stoichiometry 1801.15 grams of KClO₄ reacts with 253.5 grams of FeCl₂, if 2.50 grams of KClO₄ react how many mass of FeCl₂ will be needed?
[tex]mass of FeCl_{2}=\frac{2.50 grams of KClO_{4} x253.5 grams of FeCl_{2}}{1801.15 grams grams of KClO_{4}}[/tex]
mass of FeCl₂=0.35 grams
But 0.35 grams of FeCl₂ are not available, 150 mg= 0.150 grams (being 1000 mg= 1 grams) are available. Since you have less mass than you need to react with 1801.15 grams of KClO₄, FeCl₂ will be the limiting reagent.
Then the following rule of three can be applied: if by reaction stoichiometry 253.5 grams of FeCl₂ form 1348.05 grams of KClO₃, 0.150 grams of FeCl₂ form how much mass of KClO₃?
[tex]mass of KClO_{3}=\frac{0.150 grams of FeCl_{2}x1348.05 grams of KClO_{3} }{253.5grams of FeCl_{2} }[/tex]
mass of KClO₃= 0.7977 grams
Then, 0.7977 grams of KClO₃ are formed from the reaction of 2.50 g of KClO₄ with 150 mg of FeCl₂ in excess of H₂SO₄.
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brainly.com/question/24741074 brainly.com/question/24653699 brainly.com/question/23871710Two substances both exhibit hydrogen bonding. Substance A has a boiling point of 78.4ºC. Substance B has a boiling point of 100ºC. Which statement correctly compares the substances?(1 point)
A) Substance A has stronger bonds, and it takes more energy to undergo a phase change.
B)Substance B has stronger bonds, and it takes more energy to undergo a phase change.
C) Substance B has stronger bonds, and it takes less energy to undergo a phase change.
D) Substance A has stronger bonds, and it takes less energy to undergo a phase change.
Answer:
The answer is C
Explanation:
Just took the test
Hydrogen bonding is the intermolecular interaction that occurs due to electronegativity differences. Substance B has stronger bonds and requires more energy. Thus, option B is correct.
What is hydrogen bonding?Hydrogen bonding is present in the water molecules that is because of the electronegativity differences and the dipole-dipole interaction. The hydrogen of the water molecule is bonded to the oxygen molecule.
The hydrogen bonding affects the boiling and the melting point of the substances as more energy are required to change the phase of the matter. So when substance B requires 100ºC than substance A (78.4ºC) it shows strong hydrogen bonding.
Therefore, option B. substance B has a strong hydrogen bond is correct.
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How Does being a doormat help a tree survive winter
Answer: Trees, like all plants, are alive and require nutrients to survive. ... This dormancy is what allows trees to survive the cold winter. During dormancy, a tree's metabolism, energy consumption, and growth all slow down significantly in order to endure the harsh season of winter when water and sunlight are more scarce
Explanation: mark me brainlest plz if this helped only !
How many valence electrons are there in the molecule CH3OCH2CH3.
Answer:
There are 27 Valence electrons : )
4+1+1+1+6+4+1+1+4+1+1+1 is 27
Explanation:
There are a total of [5×1]+[2×4]+[7]=21[5×1]+[2 × 4 ] + [ 7]=21 valence electrons
If I place an egg in carbonated water will the egg gain or lose mass?
Answer:
The egg will gain mass.
Explanation:
Eggs soaked in distilled water will gain mass and appear dramatically swollen.
Answer:
Gain mass
Explanation:
Carbonated water will create a reaction inside the egg making the fluid inside the egg becoming more solid thus gaining mass
Hope this helps!
Y’all what’s this I don’t feel like doing it and I’ll give brainlist too
The lab stockroom has a bottle of Sulfuric acid labeled 15.5M. How many mL of water will you need to add to 5.41mL of the acid solution in order to get a concentration of 0.175M?
The volume of water needed to make the solution is 473.76 mL
We'll begin by calculating the volume of the diluted solution.
Molarity of stock solution (M₁) = 15.5 MVolume of stock solution needed (V₁) = 5.41 mL Molarity of diluted solution (M₂) = 0.175 MVolume of diluted solution (V₂) =?M₁V₁ = M₂V₂
15.5 × 5.41 = 0.175 × V₂
83.855 = 0.175 × V₂
Divide both side by 0.175
V₂ = 83.855 / 0.175
V₂ = 479.17 mL
Finally, we shall determine the volume of water needed.
Volume of stock solution needed (V₁) = 5.41 mLVolume of diluted solution (V₂) = 479.17 mLVolume of water =?Volume of water = V₂ – V₁
Volume of water = 479.17 – 5.41
Volume of water = 473.76 mL
Therefore, the volume of the water needed is 473.76 mL
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Pressure is exerted in all directions when an object is in fluid/water. *
A. True
B. False
Answer:
False
Explanation:
Fluid pressure has no direction, being a scalar quantity, whereas the forces due to pressure have well-defined directions: They are always exerted perpendicular to any surface. The reason is that fluids cannot withstand or exert shearing forces.
hello guys what is good!
What are all the elements of the P block?
boron, carbon, nitrogen, oxygen and flourine families in addition to the noble gases.
_________________________________________________________
also to answer the 'hello guys what is good!':nothin u?
__________________________________________
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Please help me in this question about series circuit and pararell circuit
Explanation:
it is a parallel circuit.
hope this helps you.
the mechanism of phosphorus fixation in the alkaline soil and acid soils
Answer:
absorption or precipitation or by both
Explanation:
Explain why aluminum does not react with potassium nitrate (KNO3) although it reacts with copper nitrate
Answer:
Potassium is more reactive than aluminium, so no reaction takes place. But aluminium is more reactive than copper, so it replaces the copper in copper nitrate
Explanation:More reactive metal compound + less reactive metal
-> no reaction
However
Less reactive metal compound + more reactive metal
-> more reactive metal compound + less reactive metal
This is called substitution reaction where the more reactive metal replaces the less reactive metal in the compound.
What kind of intermolecular forces act between two chloramine (NH2CI) molecules?
Explanation:
brain and heart froce acts between two chloramine
Answer:
Dispersion, Hydrogen-bonding, and Dipole forces act between two chloramine (NH2CI) molecules.
Explanation:
Dispersion is exerted between all molecules. Chloramine is polar, therefore dipole forces are present. The molecular geometry of chloramine (NH2Cl) is a trigonal pyramidal, therefore hydrogen-bonding forces are present.