Which of the following best describes a mixture? A. A substance that results when another substance is separated into its component parts B. A substance composed of two or more elements chemically combined C. A substance that results when two or more substances combine physically but not chemically D. A particle consisting of two or more atoms chemically combined
Answer: C. A substance that results when two or more substances combine physically but not chemically
You examine an ice core sample from 10,000 years ago when global temperatures were unusually high. Based upon past studies and insights from current GHG levels, we expect that atmospheric levels of carbon dioxide Group of answer choices were high but methane levels were low. and methane were unusually low. and methane were unusually high. were low but methane levels were high.
Methane was unusually high is the correct option. Hence, option B is correct.
What is methane?Methane is the simplest member of the paraffin series of hydrocarbons and is among the most potent greenhouse gases. Its chemical formula is [tex]CH_4[/tex].
As the ice compacts over some time, tiny bubbles of the atmosphere or surroundings including greenhouse gases like carbon dioxide and methane—press inside the ice. These air pocket “fossils” give samples of what the atmosphere was kind when that layer of ice formed.
Based upon past studies and insights from current GHG levels, we assume that atmospheric levels of carbon dioxide and methane were unusually low.
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I will give a brainley Hi guys I need help figuring out where the moderately reactive atoms are located on the periodic table and how the number of balance electrons of the light metals compared to those heavier than born
The moderately reactive atoms located in the periodic table are fluorine, chlorine, bromine, and iodine which means the halogens family.
The number of balance electrons of the light metals compared to those heavier by listing elements in the order of increasing atomic number.
What are halogen metals?They are the five non-metals in family 7A of the periodic table. Halogens are chemical elements that form inorganic salts. In the periodic table they are part of group 17 or family 7A.
Halogens are strong oxidants and react mainly with alkali metals (Family I A) which tend to donate an electron. They also react with metals and noble gases (Family VIII A).
The chemical elements are arranged from left to right and top to bottom in order of increasing atomic number, or the number of protons in an atom's nucleus, which generally coincides with increasing atomic mass.
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The moderately reactive atoms located in the periodic table are fluorine, chlorine, bromine, and iodine which means the halogens family.The number of balance electrons of the light metals compared to those heavier by listing elements in the order of increasing atomic number.What are halogen metals?
They are the five non-metals in family 7A of the periodic table. Halogens are chemical elements that form inorganic salts. In the periodic table they are part of group 17 or family 7A.Halogens are strong oxidants and react mainly with alkali metals (Family I A) which tend to donate an electron. They also react with metals and noble gases (Family VIII A).The chemical elements are arranged from left to right and top to bottom in order of increasing atomic number, or the number of protons in an atom's nucleus, which generally coincides with increasing atomic mass.▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
What is the lowest energy level that contains d orbitals.
Answer:
3
Explanation
it is 3
Enter your answer in the provided box. Crystalline silicon has a cubic structure. The unit cell edge length is 543 pm. The density of the solid is 2.33 g/cm3. Calculate the number of Si atoms in one unit cell. atoms/cell
Based on the calculations, the number of Si atoms in one unit cell is equal to 8 atoms/unit cell.
How to calculate the volume?Mathematically, the volume of a unit cell can be calculated by using this formula:
V = a³
V = (543)³ × (1 × 10⁻¹²)³ × (100)³
Volume, V = 1.60 × 10⁻²² cm³.
Next, we would determine the mass:
Mass = density × volume
Mass = 2.33 × 1.60 × 10⁻²²
Mass = 3.73 × 10⁻²² grams.
Also, we would determine the mass of one silicon atom:
Mass = 28.09/(6.022 × 10²³)
Mass = 4.665 × 10⁻²³ g/atom.
Now, we can calculate the number of Si atoms in one unit cell:
Number = 3.73 × 10⁻²²/4.665 × 10⁻²³
Number = 8 atoms/unit cell.
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Question 3
Not yet
answered
Points out of
If you dissolve 2.70 g of NaCl in 425 mL of water, what is the molarity of the
solution? (Report your answer to three places past the decimal point. Moodle is
looking for a number only, no units.)
Answer: 0.118M
Explanation:
The formula for molarity is: [tex]M=\frac{mol solute}{L solution}[/tex]
First, we need to find the number of moles of NaCl.
[tex]2.70gNaCl*\frac{1molNaCl}{58.44gNaCl} =0.05molNaCl[/tex]
Next, we must convert millimeters to liters. We can do that by dividing the number of mL by 1000.
[tex]\frac{425mL}{1000} =0.425L[/tex]
Now we have our needed data! All we need to do now is plug in our data to the molarity formula.
[tex]M=\frac{0.05mol}{0.425L} =0.118M[/tex]
I hope this helps! Pls mark brainliest!! :)
When you breathe, oxygen binds to the hemoglobin in your lungs and then is released into tissue cells. What type of reaction is this? A. Haber B. Irreversible C. Reversible D. Double replacement
Answer:
i believe c. reversible
Explanation:
oxygen combines with hemoglobin and detaches
Answer:
c
Explanation:
same answer i got from quiz
would you expect the substance to float or sink in water if mass is 25g and volume is 7 cm
Answer:
Sink
Explanation:
For a substance to float in water, it must be less dense than water. The density of water is 1 g/cm^3. To find the density of the substance, we can do mass/volume, which in this case is 25g/7cm^3. We see that [tex]25/7 > 1[/tex], so the substance would sink.
What volume of a 3.95 M
potassium chloride solution would
be needed to make 325 mL of a
2.76 M solution by dilution?
[?] mL of 3.95 M KCl
0.227L is the volume of a 3.95 M potassium chloride solution that would be needed to make 325 mL of a 2.76 M solution by dilution.
What are moles?A mole is defined as 6.02214076 × 10^{23} of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.
Moles of KCl in new solution
0.325dm³ x (2.76mol/dm³)
= 0.897mol.
Hence volume needed
0.897mol ÷(3.95mol/dm³)
= 0.227dm³ or 0.227L.
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Which of the following is the best definition of a chemical change?
A. A change in a substance where one or more new substances form
B. A change in a substance where no new substance forms
C. A change in a substance where energy is conserved
OD. A change in a substance where a phase change occurs
Answer:A is correct
Explanation:
45.8 grams of copper requires 1172 J of heat to reach a final temperature of 100.5 ℃. What was the initial temperature? Specific heat of copper is 0.385 J/g℃.
A. 66.5[?][?][?]
B. 122[?][?][?]
C. 34.0[?][?][?]
D. 75.2[?][?][?]
I also have no idea what the [?][?][?] is. Can someone please help me for 20 points? I desperately need help. No nonsense answers either, and show the steps pls. :')
Answer:
Option A, 66.5
Explanation:
use q (heat) = m(mass) * cp(specific heat) * deltat (change in temp)
q= 1172, m = 45.8, cp = 0.385
1172= (45.8) * (0.385) * Delta T
1172= 17.633 *DeltaT
1172/17.633 =DeltaT
66.5 =DeltaT
How much sodium bicarbonate to raise alkalinity in pool.
Answer:
A rule of thumb is that 1.5 lbs. of baking soda per 10,000 gallons of water will raise alkalinity by about 10 ppm. If your pool's pH is tested below 7.2, add 3-4 pounds of baking soda. If you're new to adding pool chemicals, start by adding only one-half or three-fourths of the recommended amount.
what happens when you mix an element into a solution with lesser reaction?
When an element is placed into a solution with lesser reaction, the reaction rate will be slow.
What is rate of a reaction?The rate of a reaction is the rate which reactants molecules are converted or the products molecules are formed.
The rate of a reaction increases with increase in concentration of the reactants and decreases with decrease in concentration.
Therefore, when an element such as a metal is placed in solution of low concentration such as very dilute acid, the reaction rate will be slow.
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You mass two substances. One substance has a mass of 22.45 g and the other has a mass of 3.1 g. What is the total mass of both objects?
Answer:
25.55 g
Explanation:
To find the total mass of both objects, you need to add the masses together.
22.45 g + 3.1 g = 25.55 g
In correct significant figures (2 sig figs to match 3.1 g), the value would be 26 g.
Answer:
answer = 25.55
Explanation:
You just have to add the mass of the two objects
When a scientific theory has been tested and proved by the scientific community, it becomes a law.
True
False
Answer:
False
Explanation:
Because laws and theories are developed for different purposes, laws never become theories, and theories do not become laws.
state three differences between temporary and permanent changes
Answer:
temporary changes are the changes which are there only for a short period if time generally temporary changes are reversible permanent changes are the changes which remain to for longer time and are not reversible
Explanation:
hope it is helpful for
how to minimize the harmful effects of power station on our environment
Instructions: In this virtual lab, you will use a virtual spectrometer to analyze astronomical bodies in space. Record your hypothesis and spectrometric results in the lab report below. You will submit your completed report to your instructor.
The main function of using a virtual spectrometer in order to analyze astronomical bodies in space is to find the chemical composition of planets and stars.
What is a Virtual Spectrometer?This refers to the instrument that is used to observe the color separation of light in a controlled experiment.
Hence, we can see that another reason for the use of a virtual spectrometer to make an analysis of astronomical bodies is to indicate the speed and direction of a star or galaxy as it spreads incoming beams of light into different spectrums.
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Webb has calculated the percent composition of a compound. How can he check his result?
Changes in which measurements do not shift the equilibrium of a chemical system
Any Change in the amount of an inert gas into a gas-phase equilibrium at constant volume does not result in a shift of the equilibrium of a chemical system. This follows the equilibrium law.
What is Equilibrium law ?According to this principle, Adding an inert gas into a gas-phase equilibrium at constant volume does not result in a shift.
This is because the addition of a non-reactive gas does not change the partial pressures of the other gases in the container.
While the total pressure of the system increases, the total pressure does not have any effect on the equilibrium constant.
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the company calculated that they would produce 4.8 tonnes of magnesium but only 3.2 tonnes was produced calculate the percentage yield
What is the molar concentration of
a solution with a volume of 1.5 L
containing 660 g Ca3(PO4)2?
Answer:
1.42 M
Explanation:
First calculate the amount of moles.
that's done by dividing the mass with the molecular mass so 660g / 310.18 g/mol = 2.13 mol
Then you can calculate the molarity by dividing the moles with the volume so 2.13 mol / 1.5 l = 1.42 M
(without rounding: 1.418531175 M)
Answer:
1.42 M
Explanation:
Acellus
does anyone understand these?
Answer:
6) 47588
4.7 * 10 power 4 ( by rounding off)
7) 1 mm ---> 1,000,000
? 120
120 * 1 / 1000000
12/ 100000
0.0012
1.2 * 10 power -4.
8) Volume is the amount of space something occupies
Which component or condition of a reaction affects the rate of the reaction but is not consumed during the course of the reaction?.
Answer:
A catalyst is a substance that can be added to a reaction to increase the reaction rate without getting consumed in the process.
Explanation:
Answer:
Catalyst
Explanation:
What volume of a 4.13 M lithium
nitrate solution would be needed tomake 195 mL of a 1.05 M solution
by dilution?
[?] L LINO3
I’ll give u 100 points if ur answer is correct
Answer:
0.0496
Explanation:
Well, there’s none!!! It’s just so easy…
Answer: 49.6
Explanation: It actually wants the answer it mL not L.
A 1. 07 g sample of a noble gas occupies a volume of 363 ml at 35°c and 678 mmhg. Identify the noble gas in this sample. (r = 0. 08206 l×atm/k×mol)
The identity of the noble gas is the sample is Krypton
Ideal Gas lawFrom the question, we are to determine the identity of the noble gas in the sample
From the ideal gas equation, we have that
PV = nRT
∴ n = PV / RT
Where P is the pressure
V is the volume
n is the number of moles
R is the gas constant
and T is the temperature
From the given information,
P = 678 mmHg = 0.892105 atm
V = 363 mL = 0.363 L
R = 0.08206 L.atm/mol.K
T = 35 °C = 35 + 273.15 K = 308.15 K
Putting the parameters into the equation, we get
n = (0.892105 × 0.363)/ (0.08206 × 308.15)
n = 0.0128 moles
Now, we will determine the Atomic mass of the sample
Using the formula,
Atomic = Mass / Number of moles
Atomic mass of the substance = 1.07 / 0.0128
Atomic mass of the substance = 83.6 amu
The noble gas with the closest atomic mass to this value is Krypton.
Molar mass of Krypton = 83.798 amu
Hence, the identity of the noble gas is the sample is Krypton
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A sample of a gas at room temperature occupies a volume of 24.0 L at a pressure of 602 torr . If the pressure changes to 3010 torr , with no change in the temperature or moles of gas, what is the new volume, V2
Answer:
V₂ = 4.80 L
Explanation:
Because you are dealing solely with pressure and volume, you can find the new volume using the Boyle's Law equation. The general equation looks like this:
P₁V₁ = P₂V₂
In this form, "P₁" and "V₁" represent the initial pressure and volume. "P₂" and "V₂" represent the new pressure and volume. You have been given all of the variables but V₂. Therefore, by plugging these values into the equation, you can simplify to find your answer.
P₁ = 602 torr V₁ = 24.0 L
P₂ = 3010 torr V₂ = ?
P₁V₁ = P₂V₂ <---- Boyle's Law equation
(602 torr)(24.0L) = (3010 torr)V₂ <---- Plug variables into equation
144448 = (3010 torr)V₂ <---- Multiply 602 and 24.0
4.80 = V₂ <---- Divide both sides by 3010
Reduction of 9-fluorenone: objective of this lab was to reduce 9-fluorenone (a ketone), to 9-fluorenol (an alcohol) using sodium borohydride as the reducing agent. experimental data: 9-fluorenone: mw 180.20 g/mol mass used 0.6 grams methanol: mw 32.04 g/mol volume used: 6ml density: 0.792 nabh4: mw 37.83 g/mol mass used 0.05 grams 9-fluorenol: mw 182.22 g/mol balanced equation for the reaction is: 4c13h8o nabh4 4ch3oh --> 4c13h10o nab(och3)4 calculate the potential yield (in grams) of 9-fluorenol for 9-fluorenone, methanol and nabh4. from these potential yields identify the limiting reagent and theoretical yield.
9-fluorenone is a limiting reagent and theoretical yield.
What is 9-fluorenol?Fluoren-9-ol is a member of the class of hydroxyfluorenes that is 9H-fluorene substituted by a hydroxy group at position 9.
Inspect stoichiometry of the given reaction as per the balanced equation below:
[tex]4C_{13}H_8O + NaBH_4 + 4CH_3 OH[/tex] → [tex]4C _{13} H _{10} O + NaB(OCH_3 )_4[/tex]
Given weight:
0.6 grams methanol
0.05 grams 9-fluorenol
0.792 [tex]NaBH_4[/tex]
Out of the three reactants, [tex]NaBH_4[/tex] acts as a reducing agent only and hence the reaction can occur only when [tex]NaBH_4[/tex] is present in relatively much smaller amounts. But the yield of the product,9-fluorenol, is not governed by its quantity.
Theoretically, when equimolar amounts of reactants ( 9-fluorenone and methanol ) are taken for reaction in presence of [tex]NaBH_4[/tex] an equivalent quantity of product, 9- fluorine is obtained, as inspected in the above stoichiometric relations. But practically we have used a lesser number of moles of 9-fluorenone than theoretically needed, hence in this case it should serve as the limiting reagent.
9- fluorenone, methanol & [tex]NaBH_4[/tex] are the reactants, while the product 9-fluorenol would be obtained = 0.0033 moles
This would represent the theoretical yield of the product 9-fluorenone, as we have used an excess of methanol thus facilitating the reaction to go to completion.
Hence, 9-fluorenone is a limiting reagent.
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Which two types of waves can transmit energy through a vacuum?
Answer:
electromagnetic waves and mechanical waves
Explanation:
I think these two kinds of waves can transmit energy through a vaccume.
Hope I helped!
Electromagnetic waves.
Gravity waves.
What is the mass of a piece of
copper that displaces 3.0 mL
of water and has a density of
9.0 g/cm³?
mass = density x volume
Answer:
27 gm
Explanation:
Well..... the volume of the copper is 3 cm^3
9.0 g/cm^3 * 3 cm^3 = 27 gm
