In the nucleus of an atom, there are 17 protons and 18 neutrons. What is the atomic number? What is the atomic mass? How many electrons are there?
Answer:
atomic number =17
mass number = 17+18= 35
A weather balloon with a volume of 3.40774 L
is released from Earth’s surface at sea level.
What volume will the balloon occupy at an
altitude of 20.0 km, where the air pressure is
10 kPa?
Answer in units of L.
Answer: The volume at an altitude of 20.0 km is 34.5289 L
Explanation:
Boyle's Law: This law states that pressure is inversely proportional to the volume of the gas at constant temperature and number of moles.
[tex]P\propto \frac{1}{V}[/tex] (At constant temperature and number of moles)
[tex]P_1V_1=P_2V_2[/tex]
where,
[tex]P_1[/tex] = initial pressure of gas = 101.325 kPa ( at sea level)
[tex]P_2[/tex] = final pressure of gas = 10 kPa
[tex]V_1[/tex] = initial volume of gas = 3.40774 L
[tex]V_2[/tex] = final volume of gas = ?
Now put all the given values in the above equation, we get the final volume of gas.
[tex]101.325\times 3.40774=10\times V_2[/tex]
[tex]V_2=34.5289L[/tex]
Thus the volume at an altitude of 20.0 km is 34.5289 L
Therefore, the final pressure of the gas will be 3.75 atm
Las Vegas, Nevada is in a desert. How does its rapid population growth affect the
water supply? Name at least two specific ways that human activities affect the quality
of groundwater
Answer:
Many areas of the United States experience explosive population growth. The more people that reside someplace, the more demand there is for water there. Often these urban-growth expansions are unplanned and place extraordinary stress on the water supply system, mainly on the groundwater. The stress often depletes groundwater supply, thereby causing wells to dry up. Then water must be brought from somewhere else to support the local population.
Such situations have occurred all over the United States. For example, increased population growth in the southwestern United States has significantly lowered the water table 50 to 200 feet (depending on the area) since the 1940s. Managing urban growth, efforts to reduce water demand, conservation of the resource, and attempts to increase the water supply all address the problem of exceeding water resource limits.
Human activities affect groundwater quality.
Here are some sources and possible solutions to groundwater pollution:
Agriculture—Reduce usage of pesticides and fertilizers.
Landfills—Monitor for leakage and repair linings.
Underground storage tanks—Remove damaged and unused tanks.
Household wastes—Properly dispose of household hazardous waste.
Septic tank leaks—Properly maintain and repair tanks.
Explanation:
This came from the K12 learning course read this and the answer will be there. I underlined the important parts for the answer.
Boron has an average atomic mass of 10.81. One isotope of boron has a mass of 10.012938 and a relative abundance of 19.80%. The other isotope has a relative abundance of 80.20%. What is the mass of that isotope? Report to two decimal places. amu
Answer:
11.01 amu
Explanation:
19.8% • 10.012938 = 1.982561724
10.81 - 1.982561724 = 8.827438276
8.827438276/80.2% = 11.0067808928
Answer: 11.01 amu
Explanation:
What is the acceleration of a car moving at the same speed and in the same direction?
Answer:
if it ain't changing direction the acceleration isn't being affected
A chemist prepares a solution of copper(II) sulfate by measuring out 17.2 of copper(II) sulfate into a volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's copper(II) sulfate solution.
Answer:
Concentration of the chemist's copper(II) sulfate solution is 0.43 mol/L
Note: The volume of the flask is assumed to be 250 mL
Explanation:
Since the volume of the volumetric flask is not given, we assume the volume its volume to be 250 mL.
Mass of copper (ii) sulfate = 17.2 g; molar mass of copper (ii) sulfate = 160 g/mol
Concentration in mol/L = number of moles/volume in litres
Number of moles of copper (ii) sulfate = 17.2 g / 160 g/mol = 0.1075 moles
Volume of flask in litres = 250 mL/1000 mL * 1 L = 0.250 L
Concentration = 0.1075 moles / 0.250 L = 0.43 mol/L
Therefore, concentration of the chemist's copper(II) sulfate solution is 0.43 mol/L
Answer:
0.5000
Explanation:
We can measure the concentration of the copper sulfate solution as 1.000 mol/L. Since the tank contains one half liter, the solution contains 0.5000 moles of copper sulfate.
net ionic equation of HF(aq)+RbOH(aq)=H2O(l)+RbF(aq)
net ionic equation
H⁺(aq)+OH⁻(aq)⇒H₂O(l)
Further explanationThe electrolyte in the solution produces ions.
The equation of a chemical reaction can be expressed in the equation of the ions
For strong electrolytes (the ionization rate = 1) is written in the form of separate ions, while the weak electrolyte (degree of ionization <1) is still written as an un-ionized molecule
In the ion equation, there is a spectator ion that is the ion which does not react because it is present before and after the reaction
When these ions are removed, the ionic equation is called the net ionic equation
For gases and solids including water (H₂O) can be written as an ionized molecule
So only the dissolved compound is ionized ((expressed in symbol aq)
Reaction
HF(aq)+RbOH(aq)⇒H₂O(l)+RbF(aq)
ionic equation
H⁺(aq)+F⁻(aq)+Rb⁺(aq)+OH⁻(aq)⇒H₂O(l)+Rb⁺(aq)+F⁻(aq)
net ionic equation
H⁺(aq)+OH⁻(aq)⇒H₂O(l)
How many kilpgrams are in 2.71x10^22 molecules of CO2
Answer:
mass of 1 molecule of CO2=44 g
mass of 2.71*10^22 of CO2=2.71*10^22*44=1.2*10^24g
now to convert grams into kilogram we know that
1000 g=1kg
1.2*10^24=1.2*10^24/1000=1.2*10^21
According to Avogadro's number concept,there are 1.979×10[tex]^-3[/tex] kilograms in 2.71 ×10²² molecules of CO₂.
What is Avogadro's number?Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.
It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .
According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.
Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number. Mass is calculated as, number of molecules/Avogadro's number×molar mass
Substitution in above formula gives, mass=2.71×10²²/6.023×10²³×44=1.979 g or 1.979×10[tex]^-3[/tex] kg.
Thus, there are 1.979×10[tex]^-3[/tex] kg in 2.71×10²² molecules of carbon dioxide.
Learn more about Avogadro's number,here:
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A) Earlier you were told that of all of the 14 solutes you will be studying, the only one that is not appreciably ionized in water is aqueous ammonia. What does this statement imply about the equilibrium point of the reaction involving aqueous ammonia/ammonium hydroxide?B) Use your results and conclusions from part (a) to explain why a complicated name like Aqueous ammonia/ammonium hydroxide is used for this solution?
Answer:
Throughout the overview section following portion, the description and according to particular circumstance is defined.
Explanation:
As per the question,
⇒ [tex]NH_3(aq)+H_2O\leftrightarrow NH_4+(aq)+OH-(aq)[/tex]
A weak basis seems to be NH3. It serves as a base since the aqueous solution or phase is protonated. But NH3 +, just becoming a weak base, is therefore deprotonated into form NH3, and therefore also 90% of ammonia becomes found throughout NH3 state in aqueous solution.⇒ [tex]NH_3+(aq) \leftrightarrow NH_3(aq)+H+(aq)[/tex]
However, it is also available in NH3 form throughout the aqueous solution much of the moment.
Redox reactions stand for oxidation/reduction reactions. True or false: an oxidation reaction is always paired with a reduction reaction.
Answer:
The answer is: true
Explanation:
In redox reactions, the half-reactions of oxidation and reduction always occur simultaneously in pair.
The oxidation half-reaction involved the lost of electrons from a reduced substance (A) to form a oxidized substance (A⁺):
A ⇒ A⁺ + e-
In contrapossition, during the reduction half-reaction the oxidized substance (B⁺) gains electrons to form the reduced subtance (B):
B⁺ + e- ⇒ B
The overall redox reaction is obtained by the addition of the two half-reactions:
A ⇒ A⁺ + e-
B⁺ + e- ⇒ B
-----------------
A + B⁺⇒ A⁺ + B
The electrons gained by B are provided by A, which lost the same number of electrons. Thus, the oxidation/reduction reactions are paired.
Larry was told that a certain muscle cream was the newest best thing on the market and claims to double a person’s muscle power when used as part of a muscle-building workout. Interested in this product, he buys the special muscle cream and recruits Patrick and SpongeBob to help him with an experiment. Larry develops a special marshmallow weight-lifting program for Patrick and SpongeBob. He meets with them once every day for a period of 2 weeks and keeps track of their results. Before each session Patrick’s arms and back are lathered in the muscle cream, while Sponge Bob’s arms and back are lathered with the regular lotion.
Which person is the control group?
SpongeBob
SpongeBob
Patrick
Patrick
Larry
Tumu’s class was given an assignment to feature a scientist that contributed to the development of the cell theory. The class decided to use images to feature the scientist of their choice.
Which image would Tumu most likely use in his assignment to feature Rudolf Virchow?
the magnified shapes of cells in a piece of cork
the different cells that make up a plant leaf
the types of cells at work in the human body
the way root cells reproduce to increase root length
Answer:
The types of cells at work in the human body
Explanation:
Rudolf Virchow was a German physician who is known as the father of modern pathology. He contributed to the development of the cell theory by concluding that all cells come from preexisting cells. This led to the conclusion that diseases occur at the cellular level, which allowed scientists to diagnose diseases more accurately.
Considering that Virchow analyzed human cells, the image that Tumu would be most likely to use in his assignment is the one of the types of cells at work in the human body.
Answer:
D the way root cells reproduce to increase root length
Explanation:
Have a good day!
1. When waves go from one place to another, they transport
A. amplitude
C. frequency
B. wavelength
D. energy
Compound Y has a distribution coefficient of 4.0 when extracted from water with chloroform, with Y being more soluble in chloroform. How many 10.0 mL chloroform extractions would be required to extract at least 95% of Y from a 50.0 mL aqueous solution of water?
For the extraction of at least 95% of Y in water, 3 extractions are to be performed.
Distribution coefficient can be defined as the ratio of the concentration of solute in an organic solvent to water.
Distribution coefficient = [tex]\rm \dfrac{concentration\;in\;solvent}{concentration\;in\;water}[/tex]
For the first extraction, the concentration in organic solvent = X per 10 mlConcentration in water = 100-X per 50 ml
Distribution coefficient = [tex]\rm \dfrac{\frac{X}{10} }{\frac{100-X}{50} }[/tex]
4 = [tex]\rm \dfrac{\frac{X}{10} }{\frac{100-X}{50} }[/tex]
4 = [tex]\rm \dfrac{50X}{1000-X}[/tex]
4000 - 4X = 50X
X = 74.1 %
Thus, after the first extraction, the amount of Y extracted is 74.1%.
We have to extract at least 95% of Y. Thus, the second extraction is performed.
Remaining y = 100 - 74.1Remaining y = 25.9%
The concentration in organic solvent = X per 10 ml
Concentration in water = 25.9 -X
Distribution coefficient = [tex]\rm \dfrac{\frac{X}{10} }{\frac{25.9-X}{50} }[/tex]
4 = [tex]\rm \dfrac{\frac{X}{10} }{\frac{25.9-X}{50} }[/tex]
4 = [tex]\rm \dfrac{50X}{259-X}[/tex]
1036 - 4X = 50X
X = 19.2%
Thus, after the second extraction the amount of Y extarcted = first extraction + second extraction
The amount of Y extracted = 74.1 + 19.2 %
The amount of Y extracted = 93.3%
To reach at least 95% extraction, the third extraction has to be performed.The remaining Y for third extraction = 100 - 93.3
The remaining Y for the third extraction = 6.7%
Concentration in water = 100 - 6.7
Distribution coefficient = [tex]\rm \dfrac{\frac{X}{10} }{\frac{6.7-X}{50} }[/tex]
4 = [tex]\rm \dfrac{\frac{X}{10} }{\frac{6.7-X}{50} }[/tex]
4 = [tex]\rm \dfrac{50X}{67-X}[/tex]
268 - 4X = 50X
X = 5.0%
The total extraction after third extraction = 93.3 + 5%
The total extraction after third extraction = 98.3%.
Thus for the extraction of at least 95% of Y in water, 3 extractions are to be performed.
For more information about the distribution coefficient, refer to the link:
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What is the chemical name of the compound NH4SCN?
Its called "Ammonium thiocyanate" Have a great day!! <3
Answer:
it is called Ammonium Thiocyanate or Thiourea
Explanation:
it is made made up of 2 nitrogen atoms, 4 hydrogen atoms, 1 sulfur atom and 1 carbon atom. stay safe and have a great day! TPWK
Metamorphic rocks with a non-foliated texture show metamorphic change that involves ____.
a.
mineral grains arranging into layers
b.
growth in the size of the mineral grains
c.
mineral grains flattening under pressure
d.
mineral grain melting
Answer:
b. growth in the size of the mineral grains
Explanation:
Non-foliated texture shown by a metamorphic change is depicted by growth in the size of the mineral grains.
Examples of non-foliated metamorphic rocks are quartzite and marble. In these metamorphic rocks, mineral grains are not aligned with their long axis. Non-foliated texture occurs under high temperature and low pressure conditions.As minerals are able to grow, the size can be used to show a metamorphic change.Answer:
its b home slice
Explanation:
no question................................
Answer:
ok
Explanation:
Urgent help me please answer it if you know it
What color change is exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide ? a. colorless to pink b. pink to colorless c. no color change d. yellow to blue e blue to yellow
The color change exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide is pink to colorless.
An indicator is an organic dye which changes color in acidic, basic and neutral medium.
Phenolphthalein is an example of an indicator. When aqueous acetic acid is titrated against aqueous sodium hydroxide, the indicator may be added to the basic solution.
Phenolphthalein has a pink color in a basic medium. As the acid is added gradually, the solution turns colorless at end point.
Hence, the color change exhibited by phenolphthalein during a titration of aqueous acetic acid with aqueous sodium hydroxide is pink to colorless.
Learn more: https://brainly.com/question/2728613
Muscles in a kangaroo’s legs work because of the cells that make up the muscle. Which component of cell theory does this best illustrate?
( science )
Answer:
cells are a basic unit of structure and function all things
Potassium hydroxide has the chemical formula KOH. It feels slippery and is used in cleaning liquids. Based on this description, potassium hydroxide is most likely a(n) A acid. B base. с neutral solution. D pH indicator.
Answer:
it should be a base
Explanation:
this is because solutions such as bleach are usually slippery on the hands, and mostly bases are in cleaning solutions
10 things you should never do while making a measurement in chemistry
Answer:
Measure at the top of the meniscus
Hold the container (it is unsteady)
Explanation:
I'm really, really, sorry. I took chemistry in 6th grade and I'm in 8th, and I don't remember the entire list. This is all I could think of.
How many different E2 products are expected in the reaction of 3-bromo-1,1-dimethylcyclohexane with NaOCH2CH3?
A) only 1
B) 2
C) 3
D) 4
An isotope of the element fluorine has 9 protons and 10 neutrons. What is the name of this isotope?
fluorine
Answer:
fluorine atom
Explanation:
What mass of 2-naphthol would have to be ingested by each rat in a sample set of rats in order to kill half the population of rats? Assume each rat weighs 230 g. Show your calculations for full credit.
Answer:
303.6 mg
Explanation:
Given that:
The lethal dose [tex]LD_{50}[/tex] = 1320 mg/kg
The weight of the rat = 230 g
The lethal dose is the dose of a substance likely to cause death. SO a lethal dose of 50 will cause the death of 50% of the sample of test animals.
Therefore;
The mass of 2-naphthol that would have been ingested by each rat in a sample set of rats in order to kill half the population of rats will be equal to:
[tex]=\dfrac{LD_{50}}{1000} \times wt \ of \ rat[/tex]
[tex]=\dfrac{1320}{1000}\times 230[/tex]
= 303.6 mg
The autoignition of both ethanol and octane occurs at 363 oC. Which gas sample contains the gas molecules that have a greater average kinetic energy
Answer:
See explanation
Explanation:
At the same temperature, the average kinetic energy of gases depends on the molecular mass of the gas. Hence, given a particular temperature, lighter molecules travel faster on the average than heavier molecules.
Considering ethanol and octane, The molar mass of ethanol is 46.07 g/mol while the molar mass of octane is 114.23 g/mol. Hence, ethanol has a greater average kinetic energy than octane at the same temperature.
In a vacuum, if a 0.045 kg golf ball is accelerated upward at 2.5 m/s2 by a hair dryer, how much force is required to accelerate the ball?
Answer:
F = 0.553 N
Explanation:
Given that,
Mass of a golf ball, m = 0.045 kg
Acceleration in upward direction, a = 2.5 m/s²
We need to find the force is required to accelerate the ball. Let the force be F. Using the second law of motion as follows :
F = m(a+g)
So,
F = 0.045 (2.5+9.8)
F = 0.553 N
So, the force required to accelerate the ball is 0.553 N.
What kind of mixture is sometimes difficult to distinguish form a compound? Why?
Answer:
In a heterogeneous mixture, the parts of the mixture are noticeably different from one another. In a homogeneous mixture, the substances are so evenly distributed that it is difficult to distinguish one substance in the mixture from another.
What is chemical weathering
Explanation:
Chemical weathering is caused by rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic.
help, Look at the model below. Explain what is correct and/or incorrect about the model based on scale, proportion, and quantity.