Answer:
D. All pure substances are molecules.
The correct statement about pure substances is; "All molecules are pure substances."
A pure substance contains exactly the same type of atoms. In a molecule, there can only be a particular combination of atoms.
For instance, a molecule of HCl can only contain chlorine and hydrogen atoms.
This means that every molecules are also pure substances.
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What would most likely happen if the kangaroo rats
were killed off and removed from the food chain?
Answer:
Explanation:
The number of cactus plants would increase.
After a scientist has drawn a conclusion, tests the conclusion, and is satisfied with the results,
what is the next step in the scientific process?
A.making a hypothesis
B.experimenting
C.communicating results
D.analyzing data
Answer: B
Explanation:
HELP! Which atom would be neutral?
A - an oxygen atom with 9 electrons, 8 protons, and 8 neutrons
B - an oxygen atom with 4 electrons, 6 protons, and 4 neutrons
C - an oxygen atom with 8 electrons, 8 protons, and 9 neutrons
D - an oxygen atom with 16 electrons, 18 protons, and 16 neutrons
Answer:
an oxygen atom with 8 electrons, 8 protons and 9 neutrons
An atom is called as neutral when the number of electron is equal to number of proton . Thus option C is correct.
What is neutral atom ?
Atom is the smallest unit of an element which can not be seen in with your bare eyes, due to its wavelength.
A visible light wavelength is about 0.000001 meter, where the size of an atom is 0.000000001 which is much smaller than 0.000001.
An atom has a nucleus, means it is the mass of the atom.
An atom is composed of protons, neutrons, and electrons where the protons and neutrons are combinedly form nucleus and electrons are present surrounding the nucleus.
When the number of proton and electron of an atom will be same then it is called as neutral only in normal state, but in other condition it either gain or loss electron by developing charge on it.
Neutral atoms are Oxygen, Hydrogen, Lithium, Helium etc.
Hence, option C is correct.
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Max puts cereal in a bowl and pours milk over it. Which term best describes Max’s bowl of cereal?
A. pure substance
B. homogeneous mixture
C. heterogeneous mixture
D. compound
Answer:
Heterogenous
Explanation: Because its not one uniform thing.
The term that best describes Max's bowl of cereal is a heterogeneous mixture.
A heterogeneous mixture is a chemical term that refers to those mixtures in which its components can be distinguished with the naked eye.
One of the distinctive characteristics of heterogeneous mixtures is that the substances that compose them retain their properties and can be separated by physical procedures such as:
FiltrationCrystallizationDecantationDistillationAccording to the above, Max's bowl is an example of a heterogeneous mixture because milk and cereals can be distinguished with the naked eye and these can be separated using a physical procedure.
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List of choices for questions 20-24: A. (1) CH3MgBr, (2) H3O , (3) CH3MgBr, (4) H3O B. (1) LDA, (2) CH3I, (3) H3O C. (1) CH3MgBr, (2) H3O , (3) NaBH4, (4) H3O D. (1) DIBAH, (2) H3O E. (1) NaOH, heat, (2) SOCl2, (3) CH
Answer:
h30
Explanation:
compared to those
5. Electrons farther away from the nucleus in an atom have
closer to the nucleus.
O A. lower energy
OB. higher energy
O C. the same energy
O D. higher or lower energy, depending on the element
Explanation:
higher or lower energy, depending on the element
Answer:
B
Explanation:
A photon of 498nm was emitted from a silicon atoms. Calculate the energy of all the atomic levels of silicon and show that the atomic levels are quantized.
The Energy of a photon in an atomic level, E = hc / λ
where
h=Planck's constant =6.626 × 10^{−34}Js
c=speed of light=3×10^8m/s
λ = photon's wavelength (metres),
E={6.626×10^{-34}Js × 3× 10^{8}m/s / {498}m/s
E= 3.99×10^{-28}J
Because all the energy levels of electrons in an atom are quantized,and cannot exist on different values of energies between them. So, when an electron moves from one energy level to another, it would release or absorb a specific and same amount of energy. Therefore, the energy of all the atomic levels of silicon must be E= 3.99×10^{-28}J
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Hello please I need help
for the equation given, how many grams of methane will react with a 125g of oxygen
CH4 (g) + 2O2(g) -> CO2(g) +2H2O
Answer:
16
Explanation:
1) in the given equation CH₄+2O₂⇒ 2H₂O+CO₂;
M(CH₄)=12+4=16 (g/mol); M(O₂)=32 (g/mol);
2) if m(O₂)=125 gr., then ν(O₂)=m(O₂)/M(O₂)=125/32≈3.90625 (moles);
3) if in the given equation 'ν' of O₂ is 2, then the 'ν' of CH₄ is 1;
4) m(CH₄)=ν(CH₄)*M(CH₄)=1*16=16 (gr.).
Which word equation best describes the following formula equation:
4Al + 302 + 2Al2O3?
Answer:
Explanation:
The equation is not correctly written, so let's start with that.
4Al + 3O2 ====> 2Al2O3?
Totally correct, including the balance numbers, would be
4moles aluminum + 3 moles Oxygen ===> 2 moles of Aluminum Oxide
Anything else is incomplete.
Answer:
aluminum reacts with oxygen to produce aluminum oxide.
I hope this helps
As the human population has grown. Earth's ecosystems and the balance
of natural cycles have been negatively affected. What are some
examples of how the social factors of sustainability (Fig. 1-3) could be
used to help repair environmental damage caused by humans?
40 POINTS I NEEDA ASAP
Which tool can be used to measure the volume of a liquid to one decimal place?
a thermometer
a graduated cylinder
an Erlenmeyer flask
a test tube
Answer:B
Explanation:
Answer:
B. a graduated cylinder
true or false? scientists who study processes that take millions of years cannot conduct experiments
Answer:
true
Explanation:
earth haven't been around for 1 million years yet
Answer:
true
Explanation:
they wouldnt be alive to complete the process
Which subatomic particle is important in chemical building and helps determine chemical properties
Explanation:
Since Z is EXPLICITLY determined by the number of protons, massive, positively charged particles, present in the element's nucleus, the proton must be the greatest determinant. Of course, it is the electrons that actually do the chemistry, but Z defines the element.
Illustrate the law of law of multiple proportions using the formation of SO2 and SO3 by sulphur and oxygen
As illustrated from law of multiple proportion, the mass of the oxygen which combined with a fixed mass of the sulphur is in simple whole number ratio of 2 is to 3 (2:3).
The law of Multiple proportion states that when two elements combine to form more than one compound, the mass of the second element, which combines with a fixed mass of the first element, will always be ratios of small whole numbers.
To illustrate the law of multiple proportion from sulphur and oxygen, we use the given compounds.
The reaction of oxygen with sulphur to form SO₂ and SO₃:
[tex]S \ + \ O_2 \ -----> SO_2\\\\2SO_2 \ + \ O_2 \ ---> \ 2SO_3[/tex]
atomic mass of oxygen = 16 g
atomic mass of sulphur = 32 g
In the formation of SO₂:mass of sulphur = 32 g and mass of oxygen = (2x16) = 32 g
In the formation of SO₃:mass of sulphur = 32 g and mass of oxygen = (3 x 16) = 48 g
Notice, while mass of sulphur is constant, mass of oxygen changed.
The ratio of mass of oxygen in the given two compounds = 32g : 48g = 2:3
Thus, based on the law of multiple proportion, the mass of the oxygen which combined with a fixed mass of the sulphur is in simple whole number ratio of 2 is to 3 (2:3).
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Fine the volume in dm³ and in Ml of a 0.505 mol/dm of NaCH required to react with 40Ml of 0.505 molar concentration of H2SO4
watch u know bout rolling down in the deep...
It is difficult to measure the volume of a gas
Answer:
Gases are more difficult to measure than liquids, because measured volumes are highly affected by temperature and pressure. Gas meters measure a defined volume, regardless of the pressurized quantity or quality of the gas flowing through the meter.
Explanation:
It is difficult to measure the volume of agas because measured volumes are highly affected by temperature and pressure.
This is science not chemistry
That is actually physics because it talks about motion.
All living organisms are made of
They are the smallest units of a living.
thing that can perform all life processes.
A. stones
B. cells
C. water drops
D. bricks
3. Based on the following balanced equation:
2 C H20 + 13 02 8 CO2 + 10 H2O
a. How many moles of O2 are required to react completely with 4.00 moles of C4H10?
3.00 6.00 8.00 10.00 13.00 16.00 20,00 23,00 26.00
b. How many moles of CO2 are produced after complete reaction of 4.00 moles of C H10?
3.00 6.00 8.00 10.00 13,00 16.00 20.00 23.00 26.00
c. How many moles of H2O are produced after complete reaction of 4.00 moles of C&H10?
3.00 6.00 8.00 10.00 13.00 1.6.00 20.00 23,00 26.00
Answer:
A. 26 moles O2
B. 16 moles CO2
C. 20 moles H20
Explanation:
a. 4 moles C4H10 x [tex]\frac{13 moles O2}{2 moles C4H10}[/tex] = 26 moles O2
B. 4 moles C4H10 x [tex]\frac{8 moles CO2}{2 moles C4H10}[/tex] = 16 moles CO2
C. 4 moles C4H10 x [tex]\frac{10 moles H2O}{2 moles C4H10}[/tex] = 20 moles H20
Use the coefficients of the balanced equation to make the convertions
A mixture of copper sulfate and water is heated, leaving a residue of copper sulfate in the container. Which method was used to separate the mixture?
A. evaporation
B. chromatography
C. distillation
D. filtration
Evaporation.
Also, it is not set to be a certain letter as for abcd
A beggar wrapped himself with a few layers of newspaper on a cold winter night. This helped him to keep himself warm because:
(a) friction between the layers of newspaper produces heat.
(b) air trapped between the layers of newspaper is a bad conductor of heat.
(c) newspaper is a conductor of heat.
(d) newspaper is at a higher temperature than the temperature of the surrounding.
the one who gets its correct will be marked as the brainliest and also be followed by me!!
P.S. have a great Sunday :)
Answer:
(b)The air trapped between the layers of newspaper is a bad conductor of heat.Thus the layers of newspaper helped the beggar to keep himself warm
Hey there!
I believe your answer would be "Air trapped between the layers of newspaper is a bad conductor of heat."
Hope this helps!
Have a great day!
Stowing items and come across an aerosol battle of hairspray what should you do?
You are stowing items and come across an aerosol bottle of hairspray. W should you do? Please choose all that apply. Stow the hairspray Raise an Andon Remove it and secure it with bubble wrap Place a Flammable sticker on the bottle Submit
HCl reacts with O2 as follows: 4HCl+O2→2Cl2+2H2O When 1.79 g of HCl reacts with 5.68 g of O2 , which statement applies?
the statements that are applicable are the ones that mention HCl being a limiting reactant, or the one that includes that the maximum amount of Cl gas that can be produced is 1.74g
what ways we can prevent rusting? Explain.
Answer:
By electroplating
Explanation:
The metal which requires to be protected from rust is connected to the anode while a lower metal in the series is connected to the cathode, the a complete circuit is made and current is passed through the circuit there by resulting to the coating of the metal at the anode.
explain the concept of dihyric alcohols
Answer:
An alcohol that contains two hydroxyl groups
Which of the following statements best defines the actual yield of a reaction? (5 points)
Select one:
a.The amount of product measured after a reaction
b.The ratio of measured yield over theoretical yield
c.The maximum amount of product that can be obtained Incorrect
d.The ratio of measured yield over stoichiometric yield
Answer:
its d
. . . . . . . .. . . . . . . . .. .
If during an experiment zinc was found to be more reactive than lead or copper, zinc would be considered the strongest _____.
a. oxidizing agent
b. reducing agent
c. spectator ion
d. All of the above
acho q a letra c
obs: não tenho certeza
The volume of a gas sample is 15 L while the temperature is 50 °C. If the temperature is changed to 30 °C and the pressure remains constant, what will the new volume be? Round your answer to the correct number of significant figures. (Don’t forget to convert the temperature to the Kelvin scale by adding 273 to the Celsius temperature.)
Convert temperatures to Kelvin
[tex]\\ \sf\longmapsto 50+273=323K[/tex]
[tex]\\ \sf\longmapsto 30+273=303K[/tex]
Using Charles law
[tex]\\ \sf\longmapsto \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}[/tex]
[tex]\\ \sf\longmapsto \dfrac{15}{323}=\dfrac{V_2}{303}[/tex]
[tex]\\ \sf\longmapsto V_2=\dfrac{15(303)}{323}[/tex]
[tex]\\ \sf\longmapsto V_2=\dfrac{4545}{323}[/tex]
[tex]\\ \sf\longmapsto V_2=14.07L[/tex]
A semiconducting material is composed of 105 g of Ga, 80 g of Al, and 92.0 g of As. Which element has the largest number of atoms in this material?
Answer:
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