Scientists have changed the model of the atom as they have gathered new evidence. One of the atomic models is shown below. A purple center outlined in black with two concentric black circles around the center, the inner circle having 2 small green balls on it and the outer circle having 8 small green balls on it. What experimental evidence led scientists to change from the previous model to this one? A few of the positive particles aimed at a gold foil seemed to bounce back. The colors of light emitted from heated atoms had very specific energies. Experiments with water vapor showed that elements combine in specific proportions. Cathode rays were bent in the same way whenever a magnet was brought near them.
Answer:
B: The colors of light emitted from heated atoms had very specific energies.
Explanation:
dont know if its the same question i had on edg but i think its B. Sorry if i didnt understand the question :)
Answer:
b
Explanation:
Which of the following is true about metals?
A. They are usually less reflective in luster than metalloids.
B.
They are usually better conductors than nonmetals.
C. They are usually less malleable than nonmetals.
D.
They are usually more brittle than metalloids.
A student lives in an apartment complex next to a park and train tracks. The student observes that they can hear the train coming sooner and from farther away when they are in front of their apartment and can only barely hear the train when they are in the park despite both being the same distance from the railroad tracks.
The student developed the model above. Using the model, identify two potential wave phenomena that occur and are the reason behind why the student can only hear the train in front of the apartment complex.
A.
The train can be heard more easily in front of the apartment complex because of reflection and interference. As the sound comes from the train, the sound waves reflect off of the complex and interfere with each other increasing the amplitude of the wave to make it easier to hear.
B.
The train can not be heard as easily in the park because of reflection and diffraction. The sound reflects off of the trees in the park and diffract between the trees, this causes the waves to bend too much to be heard.
C.
The train can be heard more easily in front of the apartment complex because of diffraction and refraction. The sound waves diffract between the other buildings aiming them towards the apartment complex and then the sound refracts through the apartment complex which makes it more difficult to hear in the park.
D.
The train can not be heard as easily in the park because of interference and reflection. The other buildings in front of the park cause interference of the sound waves from the train and the trees in the park cause reflection making it too hard to hear the train.
Answer:
The answer is A
Explanation:
How many electrons are there in the only energy level of helium, a noble gas? * Two Three Six Eight
Answer:
Explanation:
Noble gases are the least reactive of all known elements. That's because with eight valence electrons, their outer energy levels are full. The only exception is helium, which has just two electrons.
Name for each compoud
1.CO
2.H2SO4
3CaCO3
4 H202
5NaF
HELP!! URGENT ASAP!! WILL GIVE BRAINLIEST TO FASTEST ANSWER!!
Answer:
This shoes the soda lime defusing to limewater turning into germinating seeding which defuses back to limewater
Explanation:
If an animal is placed into a sealed container for a short time, the oxygen level will
A. decrease and the carbon dioxide level will increase.
B. decrease and the carbon dioxide level will decrease,
C, increase and the carbon dioxide level will increase.
D. decrease and the carbon dioxide level will stay the same.
E increase and the carbon dioxide level will decrease.
Answer:
A
Explanation:
Animals take in oxygen and convert it into carbon dioxide therefore the oxygen levels will decrease and the carbon dioxide levels will increase
If an animal is placed into a sealed container for a short time, the oxygen level will: decrease and the carbon dioxide level will increase.
What happens to oxygen level inside a container:The oxygen held inside the space is quickly being consumed by the freight or because of rusting inside a space, and that encased spaces must consistently be treated as perilous. And the carbon dioxide levels on the other hand will increase.
It will not take a long time for an animal to survive under these conditions.
Thus. option A is correct.
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348 g of water starting at 4.0°Celsius is heated until his temperature is 37°Celsius. Calculate the amount of heat energy needed to cause this rise in temperature
STEP BY STEP EXPLANATION!!
Answer:
48.049 kJ or 48049 J
Explanation:
Hello again.
So we know the formula [tex]q = mc\Delta t[/tex]. c is the heat capacity but this time, it is not given. However, water has a very well known heat capacity which is 4.184 J/(g°C). This is in fact the number we refer to a calorie which is the amount of energy you burn that can raise the temperature of 1g of water by 1°C. So, plugging in values, you get the above. But double check if I am wrong.
The amount of heat energy needed to cause this rise in temperature is 48.049 kJ or 48049 J.
What is heat energy?Heat is the energy that moves from one body to another when temperatures are different. Heat passes from the hotter to the colder body when two bodies with different temperatures are brought together.
A given amount of matter's heat capacity is the amount of energy needed to raise its temperature by one degree Celsius.
The heat energy will be calculated by the formula
Q = m•C•ΔT
Where c is the heat capacity.
The m is the mass
T is the time
Mass is 348 grams
Temperature is 37°C
The change in temperature is 4.0°C to 37°C
The heat capacity of water is 4.184
Q = 348 x 4.184 x -33 = 48049.056.
Therefore, the amount of heat energy needed is 48.049 kJ or 48049 J.
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The diagram shows a model of an animal cell. Explain how you'd modify the model to show the structures in a plant cell.
Answer:to show the structures of a plant cell,add a cell wall around the membrane and increase the size of the vaculoe insidethe cell, draw green ovals to represent chloroplasts.
Explanation:
what is atomic radius
Explanation:
The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding shells of electrons. Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions of atomic radius. Three widely used definitions of atomic radius are: Van der Waals radius, ionic radius, and covalent radius
Synthesis
1 point
Balance the following chemical equation. What are the final coefficients
starting from the left and going to the right? *
AICI:
+
H2O
_Al(OH)3 +
НСІ
1,1,1,1
1, 2, 1, 2
2, 2, 2, 2.
1,3,1,3
Answer:
nãosecoi m fazoe isrspoo rqe a perugtunat iomkplnetacá
Explanationveja qeuastã onvamoetn e depois recoepe-a qui aipis onãestoácpletoma :
Identify the reaction type shown and describe the clues that were used to identify it.
Fe2O3 + 2SiO2 → Fe2Si2O7
What is the mass, in grams, of 0.450 moles of Sb?
Answer:
54.9 g
Explanation:
0.450 mol x 122g/mol
Relative and average atomic mass both describe properties of an element related to its different isotopes. Out of these two Relative atomic mas is more accurate. Therefore, 54.9 g is the mass in grams of 0.450 moles of Sb.
What is mass?Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes. It can be calculated by multiplying mass of a isotope to natural abundance of that isotope.
Average atomic mass = (mass of first isotope× percent abundance of first isotope)+(mass of second isotope× percent abundance of second isotope)
Mass of Sb= number of moles of Sb ×Molar mass of Sb
=0.450 mol x 122g/mol
=54.9 g
Therefore, 54.9 g is the mass in grams of 0.450 moles of Sb.
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explanation of atomic radius
Ah yes.
The atomic radius is basically the distance between the nucleus of the atom and the outermost electron in the farthest orbital of the atom. The more bigger the atomic radius , the less powerful is the force that holds together the nucleus and its electrons.
The first chemists, philosophers like, Aristotle were from which country?
Answer:
greece
Explanation:
aristole was particularly from stagria, greece. but most early philosophers are from greece
A cube of metal has a mass of 5.05 x 10°g and its density is known to be 12.77 g/mL, what is the volume of this metal?
A 395.5 mL
B. 2.529 mL
C. 63,910 mL
D. 64.48 ml
Answer:
Explanation:
option A is correct
How to separate these pure substance?if it is not possible, please write cannot be separate
Oxgen
Water
Gold
Carbon Dioxide
Carbon
Answer:
Oxgen- cannot be separated
Water - chemical change
Gold - cannot be separated
Carbon Dioxide - chemical change
Carbon - cannot be separated
Explanation:
A pure substance, which can either be an element or a compound, contains only one type of such element or compound. In opposition to a mixture, pure substances cannot be separated by physical means.
- Elements as a pure substance cannot be separated because it contains only one type of atom. However, compounds contain two or more types of atoms, and hence, can only be separated into its individual atoms via chemical means.
In this question, oxygen (O2), Gold (Au) and carbon (C) are all elements and hence cannot be separated. Carbon dioxide (CO2) and water (H2O) are compounds because they contain two different atoms respectively, hence, can be separated into individual atoms.
Do 2. A student determines that there are 1.3 x 1025 molecules of an unknown
substance in a 968 g sample. Which compound most likely represents this
unknown substance?
CO
CIO
2)
CO2
N203
CLEAR ALL
Answer:
The correct option is;
CO₂
Explanation:
The given information are;
The number of molecules in the substance = 1.3 × 10²⁵
The mass of the substance = 968 g
Therefore, we have;
The number of molecules in one mole of a substance = 6.02 × 10²³
The number of moles present = (1.3 × 10²⁵)/(6.02 × 10²³) ≈ 21.595 moles
Therefore, 968 g = 21.595 moles
1 mole = 968/21.595 = 44.826 g
The mass of one mole of the substance = 44.826 g
Therefore the mass of one mole of the substance is closely related to the mass of one mole of CO₂ which is 44.01 g/mol.
The correct option is CO₂
The calculation is as follows:The number of molecules in one mole of a substance should be = 6.02 × 10²³
And,
The number of moles present is
= (1.3 × 10²⁵)/(6.02 × 10²³)
≈ 21.595 moles
Now
1 mole = 968/21.595 = 44.826 g
The mass of one mole of the substance = 44.826 g
So, the mass of one mole of the substance is closely related to the mass of one mole of CO₂ i.e. 44.01 g/mol.
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how does litmus indicator work
When we mixed milk and vinegar in the lab demonstration, a/an __.
was created.
Answer:
Plastic
Explanation
Found on google
Identify the heterogeneous mixtures.
Group of answer choices
salad
water
vegetable soup
apple juice
trail mix
brass
Is burning the glass plate is physical or chemical change?
how many picoliters are in 3.16 mL
Answer:
3.16×10⁹ pL
Explanation:
Given data:
Volume in mL = 3.16
Volume in picoliters = ?
Solution:
Picoliter and milliliters are units of volume. Milliliter is greater unit than picoliter.
1 mL = 10⁹ pL
Now we will convert the 3.16 mL into pL.
3.16 mL × 10⁹ pL/ 1 mL
3.16×10⁹ pL
6. Now, revise your definition for waves to include energy and matter.
A wave is a phenomenon that...
Answer:
A wave is phenomenon that transfers energy from one point to another through a disturbance without affecting the matter.
Explanation:
A wave is phenomenon that transfers energy from one point to another through a disturbance without affecting the matter.
There are two main types of waves Longitudinal waves travels parallel to their source. For example, sound waves. Through a series of rarefactions and compressions, longitudinal waves are propagated. Transverse waves travel perpendicular to their source.After lab, all of Darrel's friends looked at his data and laughed and laughed. They told him that he was 30.8% too low in the boiling point he had just recorded. He had recorded a boiling point of 50o C on his data sheet. What is the correct boiling point of the liquid he was working with in lab?
Answer:
100°
Explanation:
For a boiling point is it always 100°
Chloe is training for her first half-marathon, which requires her to run 21.1 km. Before she runs, she carefully chooses the foods that will give her the energy her body requires for the race. She stands still at the starting line, then she starts running, her body warming up as she runs. Which three energy transformations take place in this example? Potential energy to kinetic energy Chemical energy to thermal energy Chemical energy to kinetic energy Mechanical energy to chemical energy
Answer:
The transformation is of chemical energy (use the ATP molecule as a resource) which is then transformed into mechanical energy (muscle contraction) and finally transformed into thermal energy (increase in body temperature, or sweating)
Explanation:
Energy is never lost, it is always transformed, that is why energy is yielding electronic movement and expressing itself in different ways, first as chemical energy, then as mechanical energy, and lastly as thermal energy.
It is important to clarify that the energy source of all this transformation is food and energy reserves.
Which pair of symbols represents nuclei with the same number of neutrons?
A. 56 Co and 580
B. 57Co and 58Ni
c. 57Fe and 58 Ni
D. 57Mn and 57Fe
Answer:
B
Explanation:
Mass number = number of neutrons + number of protons
Atomic number is the number of protons in the nucleus.
58Ni : 58 is the number of neutrons + number of protons
atomic number of Ni is 28. Thus, 58 -28 = 30 neutrons
57Co ; 57 is the number of neutrons + number of protons
number of Co is 27. Thus, 57 – 27 = 30 neutrons
How many carbon atoms are there in 2.23 grams of propane (C3H8)?
Answer:
3.05x10²³ (3 sig. fig.)
Explanation:
Propane (C₃H₈) is a colorless alkane gas with three carbons and eight hydrogen atoms. In 2.23 grams of propane, there are 3.05 x 10²³ carbon atoms present.
What is the number of particles/atoms?
The number of atoms or the particles being the smallest units is estimated by the product of the number of moles and Avogadro's number.
The Avogadro's number (Na) is used to determine the number of particles that have been present in a mole of a substance. A mole of a substance is said to have 6.022 × 10²³ ions, atoms, electrons, molecules, etc.
Moles of propane are calculated as,
Moles = mass ÷ molar mass
= 2.23 ÷ 440.094
= 0.05057
Now, the number of particles is calculated as,
Number = moles × Avogadro's number
= 0.05057 × 6.022 × 10²³
= 3.05 x 10²³
Therefore, 3.05 x 10²³ carbon atoms are present in 2.23 grams of propane.
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What is Chlorofluorocarbons?
Answer:
Chlorofluorocarbons and hydrochlorofluorocarbons are fully or partly halogenated paraffin hydrocarbons that contain only carbon, hydrogen, chlorine, and fluorine, produced as volatile derivative of methane, ethane, and propane. They are also commonly known by the DuPont brand name Freon.
Explanation:
Answer:
Explanation: Chlorofluorocarbons and hydrochlorofluorocarbons are fully or partly halogenated paraffin hydrocarbons that contain only carbon, hydrogen, chlorine, and fluorine, produced as volatile derivative of methane, ethane, and propane. They are also commonly known by the DuPont brand name Freon
hope that helps.↑Please help!!!
When 38 g of a metal at 92 °C is added to
43 g of water at 22°C, the temperature of the
water rises to 30°C. What is the specific heat
capacity of the metal? Assume no heat was
lost to the surroundings.
Answer in units of
J/g degrees C
The specific heat capacity of the metal : 0.610 J/g° C
Further explanationThe law of conservation of energy can be applied to heat changes, i.e. the heat received/absorbed is the same as the heat released
Q abs = Q received
Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
∆T = T(final temp) - T(initial temp)
mass of metal = 38 g
T initial metal = 92 °C
mass of water = 43 g
T final water = 30 °C
T initial water = 22°C
c water = 4.18 J/g° C
Heat absorbed by water[tex]\tt Q=m.c.\Delta T\\\\Q=43\times 4.18\times (30-22^oC)\\\\Q=1437.92~J[/tex]
the specific heat capacity of the metalQ water = Q metal
[tex]\tt 1437.92=38\times c\times (92-30)\\\\c=0.610~J/g^oC[/tex]