Answer: Spun yarn is made by twisting staple fibers together
To make a cohesive thread Or “single”. Twisting fibers, into yarn in the process called spinning can be dated back to the upper Paleolithic. Yarn spinning was one of the first processes to be industrialized.
Explanation:
Which of the following aqueous solutions has the lowest pH? Why?
a. 0.1 M HCl;
b. 0.1 M acetic acid (pKa = 4.86);
c. 0.1 M formic acid (pKa = 3.75
When is a chemical equation considered balanced
Answer:
If each side of the equation has the same number of atoms of a given element, that element is balanced. If all elements are balanced, the equation is balanced.
Explanation:
An ice cube melts in the hot sun. Is this exothermic or endothermic and
why?
Answer:
Endothermic
Explanation:
In order to melt the ice cube, heat is required, so the process is endothermic. Endothermic reaction In an endothermic reaction, the products are higher in energy than the reactants. Therefore, the change in enthalpy is positive, and heat is absorbed from the surroundings by the reaction.
What is the oxidation number of P in PF6−?
Which temperature is warmest
A. 0°C
B. 273 K
C. 32°F
D. 30°C
Answer:
your answer should be B.273 K
Explanation:
Explain how Bohr's model built on the ideas of Einstein and Planck.
Explanation:
Bohr built on Nicholson's idea by adopting the requirement that the angular momentum can have only certain discrete values related to Planck's constant. However Bohr's atom has many orbits for the electrons.
What mass is contributed by Br-79?
Answer:
Calculate the mass of BR -79? Bromine has 2 naturally occurring isotopes (Br-79 and Br-81) and has an atomic mass of 79.904 amu
Explanation:
if i get this wrong srry
Write the net ionic equation for the acid-base reaction
PH3(aq) + HCl(aq) - PH4Cl(aq)
Explanation:
i dont understand dont you already have the equation?
The net ionic equation for the acid-base reaction PH[tex]_3[/tex](aq) + HCl(aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]Cl(aq) is PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ .
What is net ionic equation?Chemical reaction equations can be written in a variety of ways. Unbalanced chemical equations, which identify the species involved, balanced chemical equations, which identify the number and type of species, molecular equations, that also express compounds as molecules rather than component ions, and net ionic equations, which only address the species which contribute to a reaction, are some of the most popular.
A chemical equation for just a process known as the net ionic equation only includes the species that are really involved in the reaction.
PH[tex]_3[/tex](aq) + HCl(aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]Cl(aq)
PH[tex]_3[/tex](aq) + H⁺ (aq) + Cl⁻ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ (aq) + Cl⁻ (aq)
PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺
Therefore, the net ionic equation for the acid-base reaction is PH[tex]_3[/tex](aq) + H⁺ (aq) [tex]\rightarrow[/tex] PH[tex]_4[/tex]⁺ .
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Calculate the number of moles of solute in 431.9 L of 0.722 M sodium cyanide.
Answer:
[tex]312 \ mol \ solute[/tex]
General Formulas and Concepts:
Chemistry
Molarity = moles of solute / liters of solutionExplanation:
Step 1: Define variables
M = 0.722
L = 431.9
m = x
Step 2: Solve for x
Substitute: [tex]0.722 \ M=\frac{x \ mol}{431.9 \ L}[/tex]Isolate x: [tex]311.832=x \ mol[/tex]Rewrite: [tex]x=311.832 \ mol[/tex]Step 3: Check
Our smallest sig figs is 3. Follow sig figs rules.
[tex]311.832 \ mol \approx 312 \ mol \ solute[/tex]
What is the density of a glass piece that has mass of 18 g and a volume of 24 mL?
Answer:
The answer is 0.75 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question we have
[tex]density = \frac{18}{24} = \frac{3}{4} \\ [/tex]
We have the final answer as
0.75 g/mLHope this helps you
What is the name of the process that is used to clean up environmental waste and how does it work?
Answer:
Environmental cleanup includes removal of heavy metals and other toxic contaminants from the environment and the process is called remediation.
What is the Atomic number of 12
Answer:
atomic number of 12 is MG
Explanation:
Magnesium
Question in picture!!!!!!
Answer:
6 atoms
Explanation:
Salt is water solution is made salt or water
Answer:
Both
Explanation:
because salt water comes from water mixing with salt
Which are correct ???
Answer:
last one
Explanation:
endothermic reactions release energy
is the movement of particles from an area of higher concentration to an area of lower concentration
Answer:
The answer is Diffusion.
Answer:
Hypertonic
Explanation:
How does Newton’s second law apply to the golf tee balanced on the hoop? How does Newton’s second law apply to the golf tee when the hoop is pulled away?
please answer asap
There are total three laws of newtons, first law of newtons, second law of newton and third law of newton. Therefore, when a golf club is subjected to an imbalanced force, its velocity changes, which is according to newton’s second law.
What is newton's second law?According to Newton's Second Law of Motion, acceleration (gaining speed) occurs when a force acts on a mass (object). Riding a bicycle is a great example of this rule of motion in action. The mass is represented by your bicycle. The force is generated by your leg muscles pulling on the pedals of your bicycle.
The ball remains balanced on the tee due to the balanced forces of gravity downhill and upward. Force equals mass multiplied by acceleration (f=ma). When a golf club is subjected to an imbalanced force, its velocity changes.
Therefore, when a golf club is subjected to an imbalanced force, its velocity changes, which is according to newton’s second law.
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Which of the following conclusions about the two intermolecular forces is correct? X represents London dispersion forces, and Y represents ion-dipole forces. X represents dipole-dipole forces, and Y represents ion-dipole forces. X represents hydrogen bonding, and Y represents dipole-dipole forces. X represents London dispersion forces, and Y represents dipole-dipole forces.
Answer:
X represents London dispersion forces, and Y represents dipole-dipole forces.
Explanation:
i will give the first person brainliest! please helppp
okay so the Answer is c
A 1.00 gram sample of which of the following compounds contains the greatest mass of oxygen? And explain.
1. K2O2
2. Na2O
3. BeO
Answer:
BeO will have the greatest mass composition of oxygen
Explanation:
To solve this problem, we would find the mass composition of oxygen in each of the given sample.
To find this mass composition, let us derive the molecular mass of the given species;
K₂O₂ = 2(39) + 2(16) = 110g/mol
Na₂O = 2(23) + 16 = 62g/mol
BeO = 9 + 16 = 25g/mol
Now; we know that mass of each sample is 1g;
mass composition of O in K₂O₂ = [tex]\frac{32}{110}[/tex] x 1= 0.29g
mass composition of O in Na₂O = [tex]\frac{16}{62}[/tex] x 1 = 0.26g
mass composition of O in BeO = [tex]\frac{16}{25}[/tex] x 1 = 0.64g
We can see that BeO will have the greatest mass composition of oxygen.
The mass composition of oxygen has been highest in BeO. Thus, option 3 is correct.
The molecular mass has been the mass of each element that has been present in the compound. The molecular mass of given compounds have been:
[tex]\rm K_2O_2[/tex] = 2(mass of K) + 2(mass of O)= 2 (39) + 2 (16)
= 110 g/mol
[tex]\rm Na_2O[/tex]= 2(mass of N) + mass of O= 2 (23) + 16
= 62 g/mol
BeO = mass of Be + mass of O= 9 + 16
= 23 g/mol
The mass composition of oxygen in 1 gram of the following compounds have been:
Mass composition = [tex]\rm \dfrac{Mass\;of\;Oxygen}{Molecular\;mass\;of\;compound}\;\times\;weight\;of\;sample[/tex]
[tex]\rm K_2O_2[/tex] = [tex]\rm \dfrac{32}{110}\;\times\;1\;gram[/tex][tex]\rm K_2O_2[/tex] = 0.29 grams
[tex]\rm Na_2O[/tex] = [tex]\rm \dfrac{16}{62}\;\times\;1\;gram[/tex][tex]\rm Na_2O[/tex] = 0.26 grams
BeO = [tex]\rm \dfrac{16}{23}\;\times\;1\;gram[/tex]BeO = 0.64 grams.
The mass composition of oxygen has been highest in BeO. Thus, option 3 is correct.
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Please help
It’s super quick
Answer:
1. a
Explanation:
2. c
Answer:
1 is A number two is C
What volume of a 0.155 M potassium hydroxide solution is required to neutralize 25.7 mL of a 0.388 M hydrobromic acid solution
Answer: Therefore, the volume of a 0.155 M potassium hydroxide solution is 56.0 ml
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
According to the neutralization law,
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]M_1[/tex] = molarity of [tex]HBr[/tex] solution = 0.338 M
[tex]V_1[/tex] = volume of [tex]HBr[/tex] solution = 25.7 ml
[tex]M_2[/tex] = molarity of [tex]KOH[/tex] solution = 0.155 M
[tex]V_2[/tex] = volume of [tex]KOH[/tex] solution = ?
[tex]n_1[/tex] = valency of [tex]HBr[/tex] = 1
[tex]n_2[/tex] = valency of [tex]KOH[/tex] = 1
[tex]1\times 0.338\times 25.7=1\times 0.155\times V_2[/tex]
[tex]V_2=56.0ml[/tex]
Therefore, the volume of a 0.155 M potassium hydroxide solution is 56.0 ml
How much heat would be required to convert 5.31 mol of a pure substance from a liquid at 40.0°C to a gas at 113.0°C?
Answer:
Q = 7.7 KJ
Explanation:
The complete question carries the following data:
Specific Heat Capacity of Liquid State = C(l) = 1.45 J/mol.°C
Specific Heat Capacity of Gaseous State = C(g) = 0.65 J/mol.°C
Boiling Temperature = Tb = 88.5°C
Heat of Vaporization = ΔH(vap) = 1.23 KJ/mol
Now, first we calculate the heat required (Q₁) to raise he temperature to boiling point:
Q₁ = n*C(l)*ΔT₁
where,
n = no. of moles = 5.31 mol
ΔT₁ = Temperature difference from 40°C to Tb = 88.5°C - 40°C = 48.5°C
Therefore,
Q₁ = (5.31 mol)(1.45 J/mol.°C)(48.5°C)
Q₁ = 373.4 J = 0.37 KJ
Now, we calculate the heat required (Q₂) to change its phase:
Q₂ = nΔH(vap)
Q₂ = (5.31 mol)(1.23 KJ/mol)
Q₂ = 6.53 KJ
Now, we calculate the heat required (Q₃) to raise he temperature to boiling point:
Q₃ = n*C(g)*ΔT₃
where,
n = no. of moles = 5.31 mol
ΔT₃ = Temperature difference from Tb to 113°C = 113°C - 88.5°C = 24.5°C
Therefore,
Q₃ = (5.31 mol)(0.65 J/mol.°C)(24.5°C)
Q₃ = 84.5 J = 0.08 KJ
So, the total heat required to convert 5.31 mol of this pure substance from a liquid at 40°C to a gas at 113°C is:
Q = Q₁ + Q₂ + Q₃
Q = 0.37 KJ + 6.53 KJ + 0.08 KJ
Q = 7.7 KJ
The total heat required to convert the pure substance from liquid to gas at the given temperature is 814 J.
The given parameters;
molar heat capacity of liquid, C(l) = 1.45 J/mol.⁰Cmolar heat capacity of gas, C(g) = 0.65 J/mol.⁰CThe total heat required to convert the pure substance from liquid to gas at the given temperature is calculated as follows;
[tex]Q = nc_l \Delta \theta + nc_g \Delta \theta \\\\ \Delta \theta = (113 - 40) = 73^0 C \\\\Q = (5.31 \ mol \times 1.45 \frac{J}{mol .\ ^0C} \times 73\ ^0C) + (5.31 \ mol \times 0.65 \frac{J}{mol .\ ^0C} \times 73 \ ^0C)\\\\Q = 814 \ J[/tex]
Thus, the total heat required to convert the pure substance from liquid to gas at the given temperature is 814 J.
"Your question is not complete, it seems to be missing the following information;"
How much heat would be required to convert 5.31 mol of a pure substance from a liquid at 40.0°C to a gas at 113.0°C? (molar heat capacity of liquid, C(l) is 1.45 J/mol.⁰C and molar heat capacity of gas, C(g) is 0.65 J/mol.⁰C).
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Two moles of acetyl chloride was mixed with two moles of dimethylamine. After the reaction is complete, what species can be found in the mixture
Answer:
See explanation
Explanation:
The reaction is shown in the image attached. This reaction occurs by a carbocation (ionic) mechanism.
The lone pair on the nitrogen atom attacks the carbocation leading to the formation of the product as shown in the image attached.
Since the reaction occurs in a 1:1 ratio, two moles of reactants yields two moles of product.
What are some foods that bacteria helps in the production of?
Answer:
yeasts, moulds, bread, beer, wine, ...
Explanation:
1. With the aid of a Hess cycle, determine the enthalpy of the decomposition reaction of sodium nitrate, NaNO3 to sodium nitrite, NaNO2 and oxygen, O2. [5]
Enthalpy of formation of NaNO3 = -468 kJ/mol
Enthalpy of formation of NaNO2 = -369kJ/mol
Answer:
Explanation:
2NaNO₃ = 2NaNO₂ + O₂
NaNO₃ = NaNO₂ + 1/2 O₂
- 468 kJ -369 kJ 0 kJ
enthalpy of decomposition reaction
= - 369 - ( - 468 ) kJ
= 99 kJ / mol .
What most likely to cuase the rate of a chemical reaction to increase
Answer:
An increase on temperature.
Explanation:
Answer: adding a catalyst or increasing temperature
Explanation:
28. A gas exerts pressure at 5atm at 300K. What is the pressure of the gas at 600K?
a) 1 atm b) 10 atm c).1 atm d) 100 atm
Name 2 ways heat can be transferred through convention.
Answer:
Heat can travel from one place to another in three ways: Conduction, Convection and Radiation. Both conduction and convection require matter to transfer heat. If there is a temperature difference between two systems heat will always find a way to transfer from the higher to lower system.
Explanation:
The critical resolved shear stress for a metal is 35 MPa. Determine the maximum possible yield strength (in MPa) for a single crystal of this metal that is pulled in tension.
Answer:
The maximum possible yield strength for a single crystal is 70 MPa.
Explanation:
To find the maximum possible yield strength for a single crystal we need to use the following equation:
[tex]\sigma_{y} = \frac{\tau_{CRSS}}{m_{max}}[/tex]
Where:
[tex]m_{max}[/tex] is the maximum value for Schmid factor
[tex]\tau_{CRSS}[/tex] is the critical resolved shear stress = 35 MPa
[tex] \sigma_{y}[/tex] is the yield strength =?
The Schmid factor is given by:
[tex]m = cos(\phi)cos(\lambda)[/tex]
And its maximum value is obtained when λ = 45° and Φ = 45°, so:
[tex] m = cos(45)cos(45) = 0.5 [/tex]
Finally, the maximum possible yield strength is:
[tex]\sigma_{y} = \frac{\tau_{CRSS}}{m_{max}} = \frac{35 MPa}{0.5} = 70 MPa[/tex]
Therefore, the maximum possible yield strength for a single crystal is 70 MPa.
I hope it helps you!
