Answer:
+5
Explanation:
You use the rules for oxidation numbers to calculate that the oxidation number of N is +5.
The molar mass of lithium carbonate is equal to 73.9 g/mol. Answer the following questions. 1) What mass of lithium carbonate is required to prepare 500.0 mL of a 0.250 M Li2CO3 solution
Answer:
9.2375 grams of lithium carbonate is required to prepare 500.0 mL of a 0.250 M Li₂CO₃ solution.
Explanation:
Molarity is a measure of the concentration of a substance and is defined as the number of moles of solute that are dissolved in a given volume.
The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:
[tex]molarity=\frac{number of moles of solute}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].
In this case:
molarity= 0.250 Mnumber of moles of solute= ?volume= 500 mL= 0.5 L (being 1000 mL= 1 L)Replacing in the definition of molarity:
[tex]0.250 M=\frac{number of moles of solute}{0.5 L}[/tex]
Solving
0.250 M*0.5 L = number of moles of solute
0.125 = number of moles of solute
If the molar mass of lithium carbonate is equal to 73.9 g/mol, then the required mass of the compound can be calculated by:
[tex]73.9 \frac{g}{mol}*0.125 moles= 9.2375 grams[/tex]
9.2375 grams of lithium carbonate is required to prepare 500.0 mL of a 0.250 M Li₂CO₃ solution.
The mass of lithium carbonate required to prepare 500.0 mL of a 0.250 M Li₂CO₃ solution is 9250.0 grams.
The molar mass, also known as the molecular weight, is the mass of one mole of a substance. It is expressed in units of grams per mole (g/mol). The molar mass of a compound is calculated by adding up the atomic masses of all the atoms in its chemical formula.
Given:
Volume = 500.0 mL = 500.0 cm³
Concentration = 0.250 M (moles per liter)
Molar mass of lithium carbonate (Li₂CO₃) = 73.9 g/mol
Use the formula:
Mass = Volume × Concentration × Molar mass
Substitute the values in the above equation:
Mass = 500.0 cm³ × 0.250 mol/L × 73.9 g/mol
= 9250.0 g
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You have at your lab bench the following chemicals: NaH2PO4(s), Na2HPO4(s), Na3PO4(s) and deionized water. You also have standard glassware available. Describe how you would make 1.00 L of buffer with a pH of 7.00 using only solid materials and deionized water so that the concentration of the weak acid in the buffer is 0.150 M.
Answer:
Weigh 17.997g Na2HPO4 and 13.486g of NaH2PO4 dissolving those salts in 1.00L of deionized water
Explanation:
A buffer is made with the mixture of a weak acid and its conjugate base. We have as first to find the correct mixture based on the pKa's of the acids:
pKa H3PO4- NaH2PO4 = 2.148
pKa NaH2PO4 - Na2HPO4 = 7.198
pKa Na2HPO4 - Na3PO4 = 12.375
A buffer works in a range of pH's of pKa±1. Thus, we choice NaH2PO4 - Na2HPO4.
The first equation that we can write is:
NaH2PO4 = 0.150 moles -Because the concentration of the weak acid is 0.150M, in 1L = 0.150moles
Using H-H equation for this mixture:
pH = pKa + log [Na2HPO4] / [NaH2PO4]
pH is desire pH = 7.00
pKa is 7.198
[Na2HPO4] and [NaH2PO4] could be taken as the moles of each salt.
Replacing:
7.00 = 7.198 + log [Na2HPO4] / [0.150moles]
-0.198 = log [Na2HPO4] / [0.150moles]
0.6339 = [Na2HPO4] / [0.150moles]
0.095 moles = [Na2HPO4]
The mass of each salt that we must weigh is:
NaH2PO4 -Molar mass: 119.98g/mol-
0.150mol * (119.98g/mol) = 17.997g Na2HPO4
Na2HPO4 -Molar mass: 141.96g/mol-
0.095 moles * (141.96g / mol) = 13.486g of NaH2PO4
Thus, to prepare the buffer we have to:
Weigh 17.997g Na2HPO4 and 13.486g of NaH2PO4 dissolving those salts in 1.00L of deionized water
does isomers have the same physical and chemical properties
Isomers are compounds with different physical and chemical properties but the same molecular formula. ... Structural isomers have the same molecular formula but a different bonding arrangement among the atoms. Stereoisomers have identical molecular formulas and arrangements of atoms.
When a balloon containing 635 mL of air is taken from sea level (at standard pressure) to a higher altitude, the balloon expands to 829 mL. What is the air pressure at this new altitude (in atm)?
Answer:
0.766atm
Explanation:
Boyles law
P1V1=P2V2
1×635=P2×829
P2=635/829
P2=0.766atm
Carbon dioxide had how many nonbonding electron pairs in its electron arrangement?
A. 2
B. 4
C. 8
D. 6
E. 3
Answer: A.) 2 is the answer.
Explanation:
How to do 3 and 4 questions
Answer:
3) Q = -836.8 J.
4) Q = 950J.
Explanation:
Hello there!
In this case, for those calorimetry problems, we use the general equation:
[tex]Q=mC\Delta T[/tex]
Thus, we proceed as follows:
3) Here, the temperature difference is from 80 °C to 40 °C, the mass is 5.0 g and the specific heat 4.184 in SI units; thus, the heat is calculated as follows:
[tex]Q=(5g)(4.184\frac{J}{g\°C} )(40\°C-80\°C)\\\\Q=-836.8J[/tex]
4) Here, the temperature difference is from 100 °C to 200 °C, the mass is 5.0 g and the specific heat about 1.90 in SI units; thus, the heat is calculated as follows:
[tex]Q=(5g)(1.90\frac{J}{g\°C} )(200\°C-100\°C)\\\\Q=950J[/tex]
Regards!
NEED HELP ASAP
Question 7 (5 points)
(05.05 MC)
A synthesis reaction takes place when carbon monoxide (CO) and hydrogen gas (H2) react to form methanol (CH3OH). How many grams of
methanol are produced when 7.0 grams of carbon monoxide reacts with excess hydrogen gas? (5 points)
20 grams
7.0 grams
8.0 grams
6.1 grams
Explanation:
Write the balance equation for the reaction taking place:
CO(g) + 2H2(g) ==> CH3OH ... balanced equation
Find the limiting reactant:
moles CO present = 14 g x 1 mol CO / 28 g = 0.5 moles COmoles H2 present = 1.5 g x 2 mol H2 / 2 g = 0.75 moles H2OBecause according to the balanced equation it takes 2 moles H2 for every 1 mole CO, there isn't enough H2, so it is limiting and will dictate how much CH3OH can be made.
Mass of CH3OH produced = 0.75 moles H2 x 1 mol CH3OH / 2 mol H2 x 32 g CH3OH / mol = 12 g CH3OH
Which law is that pls hellp
Answer:
It is newton's first law of motion which states "Everybody continues to be in its state of rest or uniform motion in a straight line unless it is compelled by some external effort to change that state".
Explanation:
Calculate the pH of a 0.10 M solution of acidic acid HC2H3O2(aq) at 25 °C. Ka for HC2H3O2 = 1.8×10−5 at 25 °C g
Answer:
The answer is "3".
Explanation:
acetic acid Dissociation:
[tex]CH_3COOH \ < - - - - - - - - - - - - - \ > CH_3COO^{-}+H^{+}\\\\[/tex]
Dissociation constant of the Ka:
[tex]Ka = \frac{[CH3COO^{-}] [H^{+}]}{[CH_3COOH]}\\\\[/tex]
using the ICE table:
[tex]CH_3COOH \ < - - - - - - - - - - - - - \ > CH_3COO^{-}+H^{+}\\\\[/tex] [tex]\to 1.8 \times 10^{-5} =\frac{( x \times x) }{0.1-x} -------(2)[/tex]
x is negligible compared to Ka.
[tex]1.8\times 10^{-5} = \frac{x^2}{0.10}\\\\x^2 = 1.8 \times 10^{-6}\\\\x = 1.34 \times 10^{-3}\\\\pH = -\log [H^{+}][/tex]
From the ICE table, [tex][H^{+}] = x = 1.34 \times 10^{-3}[/tex]
[tex]\to pH = -\log(1.34 \times 10^{-3}) = 3[/tex]
Qualitatively explain the effect of changing concentration of Cu2+ on voltage using your experimental observations and the Keq values below. (No calculations are required).
(a) Cu^2+(aq) + 4NH3(aq) ⇄ [Cu(NH^3)4]^2+(aq) Keq = 1.2 x 10^12
(b) CuS(s) ⇄ Cu^2+(aq) + S^2-(aq) , Keq = 8.5 x 10^-45
Cu/Zn = 0.525 V
after 1 drop NH3: 0.505 V
after 2 drops NH3: 0.435 V
Cu/Zn = 0.510 V
after 1 drop Na2S: 0.452 V
after 2 drops Na2S: 0.393 V
A gas cylinder with a volume of 5.00 L contains 6.00 moles of oxygen gas
at a temperature of 90.0 K. What is the pressure inside the cylinder? The
Ideal gas law constant( R) is 0.0821 L atm/mol K*
8.87 torr
8.87 atm
0.0821 atm
0.0821 torr
Answer:
8.87 atm
Explanation:
From the question given above, the following data were obtained:
Volume (V) = 5 L
Number of mole (n) = 6 moles
Temperature (T) = 90 K
Gas constant (R) = 0.821 atm.L/Kmol
Pressure (P) =?
The pressure inside the container can be obtained by using the ideal gas equation as illustrated below:
PV = nRT
P × 5 = 6 × 0.0821 × 90
P × 5 = 44.334
Divide both side by 5
P = 44.334 / 5
P = 8.87 atm
Therefore, the pressure inside the container is 8.87 atm
How many grams of BaPO3 are present in a 3.8 mole sample?
Explanation:
M(Bapo3) = 216m/mol
n = 3.8 mole
m = M × n = 216 × 3.8 = 820.8g
Consider the energy diagram below.
A graph of reaction progression on the horizontal axis versus energy on the vertical axis. A line starts flat low on the vertical axis, the flat area is labeled A. It rises sharply to peak, labeled C, then falls a short distance before levelling off, labeled D. A dotted line follows the initial line in all respects except that it peaks higher directly above C; that peak is labeled B.
Which statement best describes the diagram?
A. The pathway A-B-D involves a catalyst and is slower than A-C-D.
B. The pathway A-B-D involves a catalyst and is faster than A-C-D.
C. The pathway A-C-D involves a catalyst and is slower than A-B-D.
D. The pathway A-C-D involves a catalyst and is faster than A-B-D.
Answer:
Explanation:
Thank you for providing the graph which was missing in the question!
D is the correct answer because a catalyst will speed up a chemical reaction. In an exothermic reaction as shown, the catalyst also enhances the reaction so that more energy is given out.
D. The pathway A-C-D involves a catalyst and is faster than A-B-D.
because a catalyst will speed up a chemical reaction.
In an exothermic reaction as shown, the catalyst also enhances the response so that more energy is given out.
What is a catalyst?A catalyst is a substance that speeds up a chemical reaction or lowers the temperature or pressure needed to start one, without itself being consumed in the course of the reaction. Catalysis is the process of adding a catalyst to facilitate a reaction.
A chemical catalyst is a substance that causes a chemical reaction to take place in a special way than it would happen without that catalyst. as an example, a catalyst should cause a reaction between reactants to happen at a faster rate or at a lower temperature than would be possible without the catalyst.
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please help me with Chem I ONLY HAVE 5 MINUTES if methane gas (CH4) flows at a rate of 0.25L/s, how many grams of methane gas will there be in a room after 1 hour of time has passed?
Answer:
643g of methane will there be in the room
Explanation:
To solve this question we must, as first, find the volume of methane after 1h = 3600s. With the volume we can find the moles of methane using PV = nRT -Assuming STP-. With the moles and the molar mass of methane (16g/mol) we can find the mass of methane gas after 1 hour as follows:
Volume Methane:
3600s * (0.25L / s) = 900L Methane
Moles methane:
PV = nRT; PV / RT = n
Where P = 1atm at STP, V is volume = 900L; R is gas constant = 0.082atmL/molK; T is absolute temperature = 273.15K at sTP
Replacing:
PV / RT = n
1atm*900L / 0.082atmL/molK*273.15 = n
n = 40.18mol methane
Mass methane:
40.18 moles * (16g/mol) =
643g of methane will there be in the roomThe bond angles marked a, b, and c in the molecule below are about __________, __________, and __________, respectively. Select correct answer. Select correct answer. 120°, 109.5°, 120° 90°, 90°, 90° 109.5°, 120, 109.5° 109.5°, 109.5°, 109.5° 109.5°, 109.5°, 90°
Answer:
109.5°, 120°, 109.5°
Explanation:
The bond angles that are marked as a, b and c in the given molecules is in the order of :
Angle a : 109.5°
Nitrogen is [tex]$sp^3$[/tex] hybridized and the geometry is tetrahedral. So the bond angle is 109.5°
Angle b : 120°
Carbon is [tex]$sp^2$[/tex] hybridized, so the shape is trigonal planer and the bond angle is 120°
Angle c : 109.5°
Carbon is [tex]$sp^3$[/tex] hybridized and the geometry is tetrahedral. The bond angle is 109.5°
is a glow stick Endothermic or exothermic ?
Answer:
exothermic
Explanation:
Which of the following is true about the reaction below. Bromide acts as a nucleophile in the first step of the reaction. Bromide acts as an electrophile in the first step of the reaction. Bromide acts a a nucleophile in the second step of the reaction. Bromide acts as an electrophile in the second step of the reaction.
Answer:
Option C
Explanation:
The complete question is attached herewith
Solution
The electropositive effect of carbocation depends on the degree of conjugate structure.
It is highest for a third degree structure as compared to a second degree structure and it is the least for the first degree structure.
In this reaction Br act as a negative ion and the structure has positive charge.
Thus, Br will act as a nucleophile in the second step of the reaction as in the first step H-Br will rearrange
Option C is correct
Please hurry!!! And help!!
*URGENT*
Best answer gets marked Brainliest!
When two nitrogen atoms combine, they form a
A) Compound
B) Liquid
C) mixture
D) Molecule
Answer:
Molecule
Explanation:
N=N
the answer is liquid
Explanation:
Coz liquid is better than anyone else about the league Now guys are u doing anything for the link to know
How many neutrons are in an atom of argon–40?
Answer:
22 neutrons
Explanation:
If so please sorry
which best describes the type of titration for the graph below? O strong acid titrated with a strong base
O strong base titrated with a strong acid
O weak acid titrated with a strong base
O weak base titrated with a strong acid
Answer:
B. strong base titration with a strong acid
(i)Write two observations when lead nitrate is heated in a test tube.
(i)Name the type of reaction.
(ii)Write a balance chemical equation to represent the above reaction.
Answer:
i-When lead nitrate is heated, it decomposes into lead oxide (PbO), nitrogen dioxide (NO2), and oxygen gas (O2). The type of this reaction is thermal decomposition reaction.
A 48.5 mL sample of gas in a cylinder is warmed
from 18°C to 92°C.
What is its volume at the final temperature? (Assume constant pressure.)
Express your answer in milliliters to three significant figures.
Answer:
60.8 mL
Explanation:
Using Charles law equation;
V1/T1 = V2/T2
Where;
V1 = initial volume (mL)
V2 = final volume (mL)
T1 = initial temperature (K)
T2 = final temperature (K)
According to the information given in this question;
V1 = 48.5 mL
V2 = ?
T1 = 18°C = 18 + 273 = 291K
T2 = 92°C = 92 + 273 = 365K
Using V1/T1 = V2/T2
48.5/291 = V2/365
Cross multiply
291 × V2 = 48.5 × 365
291 V2 = 17702.5
V2 = 17702.5 ÷ 291
V2 = 60.8 mL
The compound AlP (aluminum phosphide) is a compound semiconductor having mixed ionic and covalent bonding. Calculate the fraction of bonding that is ionic.
Answer:
0.086
Explanation:
The formula for calculating the fraction of a covalent bond can be expressed as:
= exp (-0.25ΔE²)
[tex]= exp[-0.25(E_{Al}-E_{p})^2]---(1)[/tex]
from the equation above;
[tex]E_{Al}[/tex] = the electronegativity of aluminum
[tex]E_P[/tex] = electronegativity of phosphorus
Using the data from periodic table figures;
[tex]E_{Al}[/tex] = 1.5
[tex]E_P[/tex] = 2.1
∴
fraction of the covalent = exp[-0.25(1.5 - 2.1)²]
fraction of the covalent = exp(-0.09)
fraction of the covalent = 0.914
Now, the fraction of ionic bond will be = 1 - the fraction of covalent bond
= 1 - 0.914
∴
the fraction of bond that is ionic = 0.086
How many molecules of sodium fluoride (NaF) are found in 7.2 moles of sodium fluoride?
Answer:
well please answer me it's question too after you get it
Explanation:
i am also stucked in that question
No. of molecules of any substance is one mole
= Avogadro's Number = (6.022 x 10^23)
So, no. of molecules in 7.2 moles of sodium fluoride
= 7.2 × (6.022 x 10^23)
= 4.33584^24
Plss hellp which law is that?
Answer:
law of motion
Explanation:
Answer:
it is a inertia of motion because the person inside a moving bus falls forward if it is stopped suddenly.
Explanation:
Identify the conjugate base in the equation below
CH3COOH + H2O - H30* + CH3COO-
O a. CH3COO
O b. H20
O c. H30+
O d. CH3COOH
Answer:
a. CH3COO⁻.
Explanation:
Hello there!
In this case, according to the given ionization reaction of acetic acid:
CH₃COOH + H₂O --> H₃O⁺ + CH₃COO⁻
Whereas we can evidence how the CH₃COOH is the acid whereas H₂O the base, as the former donates H ions to the latter, which accepts them; we can infer that H₃O⁺ is the conjugate acid, resulting from the base and the a. CH3COO⁻ is the conjugate base, resulting from the acid.
Best regards!
when naming branched chain alkanes, the names of the alkyl substituents are listed in alphabetical order
true or false?
Answer:
False that all kalwlzsjoxla
If it takes 720. mL of 0.00125 M Mg(OH)2 to neutralize 425 mL of an HCI
solution, what is the concentration of the HCI? Mg(OH)2 + HCl →MgCl2
+ H20
Answer:
0.004235 M
Explanation:
The neutralization reaction of this question is given as follows:
Mg(OH)2 + 2HCl → MgCl2 + 2H2O
Using the formula below:
CaVa/CbVb = na/nb
Where;
Ca = concentration of acid (M)
Cb = concentration of base (M)
Va = volume of acid (mL)
Vb = volume of base (mL)
na = number of moles of acid = 2
nb = number of moles of base = 1
From the information provided in this question;
Ca = ?
Cb = 0.00125 M
Va = 425 mL
Vb = 720 mL
na (HCl) = 2
nb = (Mg(OH)2) = 1
Using the formula; CaVa/CbVb = na/nb
Ca × 425/0.00125 × 720 = 2/1
425Ca/0.9 = 2
472.2Ca = 2
Ca = 2/472.2
Ca = 0.004235 M
Name the following alkene:
CH3CH = CHCH2CH3
A. 3-pentane
B. 2-pentene
C. 2-pentane
D. 3-pentene
Answer:
2-pentene
Explanation:
The name of the alkene is 2 pentene. The correct option is B, 2-pentene.
What is 2-pentene?Alkenes with the chemical formula [tex]C_5H_10[/tex] are known as pentene. Within its molecular structure, each has one double bond.
The given alkene [tex]CH_3CH = CHCH_2CH_3[/tex] is 2-pentene because the double bond is present in the second carbon and it's pentene because there are five carbons present.
Thus, the correct option is B. 2-pentene.
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How many moles (of molecules or formula units) are in each sample?
0.2346 g C8H18
Express your answer to four significant figures.
nC8H18 =