Answer:
0.0457 M
Explanation:
The reaction that takes place is:
2HBr + Ca(OH)₂ → CaBr₂ + 2H₂OFirst we calculate how many moles of acid reacted, using the HBr solution's concentration and volume:
Molarity = Moles / VolumeMolarity * Volume = Moles0.112 M * 12.4 mL = 1.389 mmol HBrNow we convert HBr moles to Ca(OH)₂ moles, using the stoichiometric ratio:
1.389 mmol HBr * [tex]\frac{1mmolCa(OH)_{2}}{2mmolHBr}[/tex] = 0.6944 mmol Ca(OH)₂Finally we calculate the molarity of the Ca(OH)₂ solution, using the given volume and calculated moles:
0.6944 mmol Ca(OH)₂ / 15.2 mL = 0.0457 MThe concentration of KBr in a solution prepared by dissolving 2.21g of KBr in 897 g of water is __________ m.
A) 2.46.
B) 0.0167.
C) 2.07 x 10-5.
D) 0.0186.
E) 0.0207.
Answer:
E) 0.0207
Explanation:
The molal concentration, m, is defined as the ratio between moles of solute (In this case, KBr) per kg of solvent (water):
Moles KBr -Molar mass: 119g/mol-
2.21g KBr * (1mol / 119g) = 0.01857moles
Mass solvent:
897g * (1kg / 1000g) = 0.897kg
Molal concentration:
0.01857 moles / 0.897kg =
0.0207m
Right solution is:
E) 0.0207.A compound is an example of pure substance
True
False
Rocks melt at what temperature range? a. 50 to 100 degrees Celsius b. 130 to 200 degrees Celsius c. 220 to 500 degrees Celsius d. 600 to 1,300 degrees Celsius
600 and 1,300 degrees Celsius
In pretty sure
The density of aluminum is 2.7 g/cm3 and that of Al2O3 is about 4 g/cm3. Calculate the PB ratio for Aluminum. (Hint: The Pilling-Bedworth Ratio (PBR) gives the volume of oxide formed to the volume of metal atoms.)
a) 1.28
b) 0.28
c) 0.75
Answer:
1.28
Explanation:
Al = aluminium
Density of Al = 2.7g/cm³
Density of Al2O3 = 4g/cm³
Molecular weight of Aluminum = 27g/mol
Molecular weight of Al2O3= 101.96 g/mol
Pilling bedworth ratio = Rob
= M(Al2O3) * density of Al / n* molecular weight of Al * density of Al2O3
= 101.96g/mol x 2.7g/cm³/2x 27g/mol x 4g/cm³
= 275.292/216
= 1.28
From the calculation above 1.38nis the PB ratio for aluminum
how many molecules of nitrogen are in 1.25 mol N2?
Answer:
7.52 x 10²³ molecules N
Explanation:
multiply 1.25 mol of N2 by Avogadro's Number
A sample of gas occupies a volume of 350.0 mL at 840mm Hg and 33°C. Determine the volume of this sample at 600 mm By and 52°C
Answer:
V₂ = 520.42 mL
Explanation:
Given data:
Initial volume = 350.0 mL
Initial pressure = 840 mmHg
Initial temperature = 33°C (33 +273 = 306 K)
Final temperature = 52°C (52+273 = 325 K)
Final volume = ?
Final pressure = 600 mmHg
Formula:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
Solution:
V₂ = P₁V₁ T₂/ T₁ P₂
V₂ = 840 mmHg × 350.0 mL × 325 K / 306 K × 600 mmHg
V₂ = 95550000 mmHg.mL.K /183600 K.mmHg
V₂ = 520.42 mL
Chemistry problem. please help
Answer:
solid X contains only ionic bond, and solid Y contains only covalent bonds.
Explanation:
solid X contains only ionic bond, and solid Y contains only covalent bonds. Because ionic compounds they have high melting point compared to covalent compounds, ionic compound they are generally insoluble in non polar solvent such as toluene but soluble in polar solvent such as water, ionic compound they conduct electricity.
What is a solute?
A material that is dissolved in another material.
O A material in which another material is dissolved.
An area of space surrounding the nucleus.
O Chemical formulas on the left side of an equation.
Balanced or Unbalanced
K+2MgBr=KBr+Mg
What makes an object cool down?
A) adding cold molecules
B) subtracting heat molecules
C) increasing the kinetic energy of the molecules
D) Decreasing the kinetic energy of the molecules
Answer:
D) decreasing the kinetic energy of the molecules
Explanation:
Can someone answer 1
For me please?
Answer:
The answer is c.
Explanation:
What can you say about the pH before and after the last drop of HNO3 was added?
Answer:
the water symbol i forgot tho
Explanation:
hi
NaOH is a base. Therefore, the pH is initially very high and above 7. If you add HNO3, which is a strong acid and has a pH less than 7, you will lower the pH of the solution. In fact, at the equivalent curve, you will have a pH of 7 because you are mixing a strong acid and strong base. Depending on how much HNO3 is added, the pH will continue to go down.
Most elements are __ at room temperature
Answer:
Most elements are Solids at room temperature
Why is a “spark” of energy required to begin the chemical reaction of burning a fossil fuel? What is another name for this spark of energy?
Answer: a burst
Explanation: a burst of energy could be substatuded for spark of energy
A spark of energy is required to begin the chemical reaction of burning a fossil fuel because; This spark of energy is required to attain the activation energy of the reaction.
Another name for this spark of energy is Ignition.
Definition:
The activation energy of a chemical reaction is the minimum amount of energy required for the commencement of the chemical reaction.
In this case, the spark of energy is required to attain the activation energy of the reaction.
Read more:
https://brainly.com/question/7639475
If the resistance of a circuit is 3 ohms, and the voltage produced by the cell in the circuit is 12 volts, what's the magnitude of the current?
Answer:
4 AExplanation:
The magnitude of the current can be found by using the formula
[tex]i = \frac{v}{r} \\ [/tex]
v is the voltage
r is the resistance
From the question we have
[tex]i = \frac{12}{3} = 4 \\ [/tex]
We have the final answer as
4 AHope this helps you
Answer:
4A
Explanation:
The half-life of the radioisotope 158Eu is 0.77 h. How much time is required for a 160.0-g sample of 158Eu to decay to 2.07 g?
a. 3.0 h
b. 4.0 h
c. 6.0 h
d. 2.1 h
e. 4.8 h
Answer: e. 4.8 h
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for rate constant
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{0.77hr}=0.9hr^{-1}[/tex]
b) for 160.0 g to decay to 2.07 g
[tex]t=\frac{2.303}{0.9}\log\frac{160.0}{2.07}[/tex]
[tex]t=4.8hr[/tex]
The time required for a 160.0-g sample of 158Eu to decay to 2.07 g is 4.8 hours
True or False: Cohesion is the attraction between particles of the same
substance
Answer: True
Explanation:
Need help please? Thanks youu
Answer:
A
B
E
Explanation:
"Fission is the splitting of a heavy, unstable nucleus into two lighter nuclei
and fusion is the process where two light nuclei combine together releasing vast amounts of energy"
a process that releases energy is respiration
Does your heart desire my love and affection?
Yes, your heart does because everyone loves me, since I am well known as Kirby. ♥
Please help me please!!
(Picture above)
Answer:
I'll tell you how to find it, but no answers
Explanation:
It's pretty simple. Your north and south points go first, then your east and west. You look at the dot, and trace your finger down the two lines to get your lattitude and longitude. From there, you just write it out. For example, G would be at (0,0) because the lines match up at 0,0 where the point is.
What is the final pressure of 1.00 mol of ammonia gas, initially at 1.00 atm, if the volume is:___________.
a. gradually decreased from 78.0 mL to 39.0 mL at constant temperature.
1) 2.00 atm
2) 1.00 atm
3) 0.50 atm
4) Not enough data
b. increased from 43.5 mL to 65.5 mL at constant temperature.
c. decreased by 40% at constant temperature.
Answer:
The correct answer is a = 2 atm, b = 0.66 atm, and c = 1.66 atm.
Explanation:
a. When the temperature is constant, the ideal gas equation, that is, PV = nRT becomes PV = constant, or P1V1 = P2V2
Based on the given information, the pressure of the gas is 1.00 atm, the V1 of the gas is 78 ml, and the V2 of the gas is 39 ml.
Now using the above formula we get,
P2 = (P1V1) / (V2)
P2 = 1 atm * 78 ml/39 ml
P2 = 2 atm.
b) Now the volume V1 is 43.5 ml, and the volume V2 is 65.5 ml at constant temperature, P1 is 1 atm. Now P2 will be,
P2 = (P1V1) / (V2)
P2 = 1 atm * 43.5 ml/65.5 ml
P2 = 0.66 atm
c) In the given case, when the volume is decreased by 40 percent, let us consider that the volume, V1 be 100 ml, and the volume V2 be 60 ml, the P1 is 1 atm, now the P2 will be,
P2 = (P1V1) / (V2)
P2 = 1 atm * 100 ml/60 ml
P2 = 1.66 atm.
How much excess reactant remains from the reaction of 8.3g of sodium and 4.5g of chlorine?
a. 8.2g Na
b. 5.4g Na
c. 5.4g Cl2
d. 8.2g Cl2
Answer:
5.4 g Na
Explanation:
Calculate the mass of sodium chloride from both reactants. The lesser value is the amount is the theoretical yield. Subtract the mass of the calculated mass of sodium chloride from the mass of the reactants.
Can someone help me and explain why they got what they got?
Answer:
24.32 amu
Explanation:
From the question given above, the following data were obtained:
Isotope A (Mg–24):
Mass of A = 24 amu
Abundance (A%) = 79%
Isotope B (Mg–25):
Mass of B = 25 amu
Abundance (B%) = 10%
Isotope C (Mg–26):
Mass of C = 26 amu
Abundance (C%) = 11%
Average atomic mass of Mg =?
Average atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]
= [(24 × 79)/100] + [(25 × 10)/100] + [(26 × 11)/100]
= 18.96 + 2.5 + 2.86
= 24.32 amu
Thus, the average atomic mass of Mg is 24.32 amu
Which of the choices below is matter? *
electricity
wood
sound
O
fire
Answer:
Wood
Explanation:
Matter is anything that has mass. Nor sound, fire or electricity have mass which leaves wood as the final answer.
Please answer. Thank you
Answer:
Explanation:
what are tho anwser choices
Please help with the chart
Answer:
no
Explanation:
The systematic pattern for filling up the electron configuration, from low energy to high energy for an element is called the:_________
a) the Pauli exclusion principle.
b) Hund's rule.
c) Coulomb's law the Aufbau principle.
d) the Heisenberg uncertainty principle.
Answer: The Aufbau principle.
Explanation:
According to aufbau's principle of filling electronic orbitals, the sublevels with lower energies are filled up before those with higher energies. The orbitals with lower (n+l) value will be filled prior to higher (n+l) value.
Hunds rule states that an orbital can contain two electrons only if all other orbitals in that sublevel contain at least one electron.
Paulis exclusion principle states that two electrons must have opposite spin , which means that no two electrons can have same set of quantum numbers.
Heisenberg principle states that it is impossible to measure simultaneously the exact position and momentum of subatomic particle.
Answer:
option c
hope helps you have a great day
Please help!! On a timer!! If you can help me with any of the following questions please, I'm lost.
1. What is the density of a block of marble that occupies 251 cm^3 and has a mass of 933 g? Answer in units of g/cm^3
2. Lee pushes horizontally with a force of 45 N on an 18 kg mass for 12 across the floor. Calculate the amount of Lee did. Answer in units of J.
3. What is the mass number of an element with atomic number 10 and 10 neutrons.
Answer:
3. Answer= Neon (Ne) is the Group 8A chemical element that has atomic number 10 and mass 20.1797.
When forming an ion, nitrogen will have what charge?
Answer:
The valence electrons of nitrogen in its compounds are all sp³ hybridized orbitals. The formal charge on N is usually -1 for an anion, 0 for a neutral compound, and +1 in cations. A nitrogen atom with a formal charge of -3 would correspond to a nitride ion, N³⁻, which is strongly basic in aqueous solution. Hope this helps...
Explanation:
Brainliest please?
As the number of bonds increases, the strength of the bond ________.
Answer:
increases
Explanation:
