iondine
Explanation:
bromine has 185pm, astatine haa 200, iondine has 140 and lastly fluorine has 147. so iondine has the smallest atomic radius
0. 10. A black hole is a region in space where the gravational poll is so great that
It can be used to travel to another universe,
0
It consumes entire galaxies.
O
Light cannot escape
New stars are formed,
Answer:
light cannot escape new stars are formed
Explanation:
A rock mass is 100g. Determine the density of the rock if it has a volume of 20cm3.
Answer:
The answer is 5.0 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
From the question
mass = 100 g
volume = 20 cm³
We have
[tex]density = \frac{100}{20} = \frac{10}{2} \\ [/tex]
We have the final answer as
5.0 g/cm³Hope this helps you
What is the process whereby scientists check each other’s work?
A. defining the audience
B. conferencing
C. peer reviewing
D. writing
Answer:
peer reviewing
Explanation:
Its peer reviewing because there peers and there reviewing eachothers work
The process whereby scientists check each other’s work is peer reviewing.
What is peer group?Peer group are the groups of people of same age, same background with same interest.
In the peer reviewing process group of members will check, evaluate and correct each others work, which in turn help the members of the group to update their work.
Hence, option (c) is correct i.e. peer reviewing is the process whereby scientists check each other’s work.
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Part 1)
There is a storage container with 5.25 tons of Ammonia (NH3). How many molecules of Ammonia are there?
Answer:
1.69×10²⁹ molecules.
Explanation:
The following data were obtained from the question:
Mass of Ammonia (NH3) = 5.25 tons
Molecules of Ammonia (NH3) =.?
Next, we shall convert 5.25 tons to grams (g). This can be obtained as follow:
1 ton = 907184.74 g
Therefore,
5.25 ton = 5.25 ton × 907184.74 g / 1 ton
5.25 ton = 4762719.885 g
Therefore, 5.25 tons is equivalent to 4762719.885 g
Finally, we shall determine the number of molecules of ammonia, NH3 in 4762719.885 g. This can be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules. This implies that 1 mole of ammonia, NH3 also contains 6.02×10²³ molecules.
1 mole of ammonia, NH3 = 14 + (3x1) = 14 + 3 = 17 g
17 g of ammonia, NH3 contains 6.02×10²³ molecules.
Therefore, 4762719.885 g of ammonia, NH3 will contain = (4762719.885 × 6.02×10²³) / 17 = 1.69×10²⁹ molecules.
From the calculations made above,
5.25 tons (4762719.885 g) of ammonia, NH3 contains 1.69×10²⁹ molecules.
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.
The bright red line from the emission spectrum of hydrogen has a wavelength of 657 nm. What is the energy, in joules, of a single photon of this light? 4.35 x 10–40 J 3.03 x 10–28 J 3.03 x 10–19 J 4.56 x 1014 J
Answer:
3.03 × 10^-19 J
Explanation:
The energy, E, of a photon of light can be calculated by using the formula:
E = hv
Where; E is energy in Joules,
h is Planck's constant {6.626×10^−34J}
v is frequency of light
For this question, the wavelength (λ) is given, not the frequency (v).
Hence, we use;
v= c/λ
Where v= frequency, c= speed of light (3×10^8m/s), λ= wavelength (657nm)
657nm = 657 × 10^-9m
v = 3×10^8/657 × 10^-9
v = 3/657 × 10^(8--9)
v = 0.00456 × 10^17
v = 4.56 × 10^14
Since frequency (v) = 4.56 × 10^14;
E = hv
E = 6.626×10^−34 × 4.56 × 10^14
E = 30.21 × 10^(-34+14)
E = 30.21 × 10^-20
E = 3.021 × 10^-19
Therefore, the energy of the photon of light is 3.02 × 10^-19 J
please help.
In 1976, an airplane was flown at a speed of 2193 miles per hour. How many kilometers could the plane fly in 4.3 hours? Use D.A. with these conversion factors: 1mile = 5280ft 1ft =12 inches 1 inch = 2.54cm
Answer:
9429.9
Explanation:
periodt
Which of the following is a CORRECT statement?
Chemical change cannot be undone or reversed.
Physical change often cannot be undone or reversed.
In chemical change, you end up with the same substance you started with.
In physical change, particles of 2 or more substances rearrange to form new or different substance.
Answer:
Detail is given below.
Explanation:
1) Chemical change cannot be undone or reversed.
The given statement is correct. Because,
Chemical change:
The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.
These changes are irreversible .
Example:
Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood and this reaction can not be reversed.
2) Physical change often cannot be undone or reversed.
The given statement is incorrect.
Physical Change
The changes that occur only due to change in shape or physical properties but their chemical or internal composition remain unchanged.
These changes were reversible.
Example :
Water converting to Ice
Water converting to gas
3) In chemical change, you end up with the same substance you started with
The given statement is incorrect. Consider the following example.
The reaction of Hydrogen and oxygen:
H₂ (g) + O₂ (g) -------------------------------------> 2H₂O (l)
A totally new compound is formed when oxygen and hydrogen are undergo reaction which is water.
4) In physical change, particles of 2 or more substances rearrange to form new or different substance.
The given statement is incorrect.
When particles rearrange them selves the different substance is not formed. Consider the example of water when it converted into ice or vapors. Only phase is changed but water retain its properties so new substance is not formed.
What are natural resources
Answer:
resources that come from the ground or eath naturally which also means that those minerals like coal take hundreds of years to be created
What is an ionic bond?
Answer:
Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion
Explanation:
pleaseee mark brainliest <3!
A neutral (net charge
zero) atom of silicon contains:
A
28.09 electrons
B
16 electrons
C
14 electrons
D
38 electrons
Answer:
C 14
Explanation:
Silicon atom has 14 protons. Given that a positive and a negative neutralize each other you need 14 electrons to neutralize the 14 protons.
How would a flood be a limitation for synthetic polymers that rely on natural rubber in its production?
Answer:
A flood would affect the availability of a material used in making a synthetic polymer. If a flood destroys rubber trees, the availability of natural rubber would decrease, which would in turn decrease the production of synthetic polymers.
Explanation: I just did it
Answer: Sample Response: A flood would affect the availability of a material used in making a synthetic polymer. If a flood destroys rubber trees, the availability of natural rubber would decrease, which would in turn decrease the production of synthetic polymers.
Explanation:
_________ are elements of the same element that have a different _______________ due to a different number of _____________.
Answer: Isotopes
Explanation:
The atoms of a chemical element can exist in different types. These are called isotopes. They have the same number of protons (and electrons), but different numbers of neutrons. Different isotopes of the same element have different masses.
Hope this helps!
A carpenter uses sandpaper on a piece of wood. Before, the wood felt rough. After, the wood felt smooth. Did the friction between the hand and the wood increase or decrease after using the sandpaper? Describe what the sandpaper did to the wood to make it smoother.
Answer:
Friction between the hand and the wood decreased.
Explanation:
The texture of the wood went from rough → smooth! This means friction between the hand and the wood was notably decreased.
According to this prompt, the carpenter used sandpaper against the wood. Sandpaper just so happens to be a very abrasive substance. The sandpaper polished and leveled out the wood which wore all the jutting bits away.- overall, making it much smoother and more pleasant to touch!
Hope I was of assistance! Have a nice day and Spread the Love! <3
Type the correct answer in each box.
Which chemical symbols will complete the equation for this single displacement reaction?
2NaBr + Cl2 → 2 __ __ + __ 2
Answer:
2Naci+Br2
Explanation:
i hope it is help full
Answer:
Na//Cl//Br
Explanation:
What happens if you mix lithium and aluminum together?
Answer:
hello
Explanation:
do you meant something like that
Which best explains the process of meiosis?
Meiosis includes cytokinesis, which divides the cell's DNA.
Meiosis is a series of steps that divides the cell's cytoplasm.
Meiosis includes interphase, which divides the cell's cytoplasm.
Meiosis is a series of steps that divides the cell's DNA.
Answer:
D
Explanation:
Meiosis is a series of steps that divides the cell's DNA best explains the process of meiosis. Therefore, option D is correct.
What is meiosis ?A type of cell division in which each daughter cell receives half the DNA of the parent cell. In mammals, meiosis occurs during the formation of egg and sperm cells.
Due to the fact that cell division occurs twice during meiosis, a single starting cell can produce four gametes (eggs or sperm). Cells go through four stages during each round of division: prophase, metaphase, anaphase, and telophase.
Meiosis is also important for allowing genetic diversity and facilitating the repair of genetic defects via recombination.
Daughter cells are diploid after meiosis and have twice as much genetic material, which can be divided in an infinite number of ways.
Thus, option D is correct.
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What are alkali metals
Answer:
Alkali metals are highly reactive elements that appear to be silver and they are found in group 1 of the periodic table. It consists of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). As you go further down the group, the more reactive they are. Those elements all react to water and air, so they must be kept in oil to preserve their state.
Protons have a __________________ charge and are found in the area of an atom called ________________________.
Answer:
Positive
Nucleus
A student places a small amount of water in a glass dish and then carefully places a small paperclip on the surface of the water. The paperclip floats. What happens if the student adds a drop or two of dish soap to the water?
Answer:
Adding soap would cause the paper clip to fall through the water and onto the base of the dish because soap is a surfactant.
Explanation:
The concept surface tension is used here to determine what happens to the paperclip when a drop of dish soap is added to the water. Here the paperclip sink into the water.
What is surface tension?The property exhibited by the surface of a liquid in order to resist the action of an external force because of the cohesive nature of the molecules is known as the surface tension. Due to this property the surface of a liquid behaves as an extended elastic membrane.
The paperclip float on water because of the high surface tension as the water molecules at the surface are strongly attracted among themselves. But on adding one or two drops of dish soap to water causes the paperclip to sink.
The addition of the drops of dish soap to the water weakens the attraction among the water molecules and thereby lowers the surface tension. As a result of this the surface film disappears and the paperclip sink into the water.
Thus the paperclip fall into the water when a drop of dish soap is added to the water.
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Ou are subliming camphor and you note that pure camphor is condensing nicely on the cold finger. You check on the process several minutes later and you see that the amount of camphor on the cold finger has not changed appreciably since the last time you looked at it. However, there is still plenty of impure camphor left at the bottom of the flask. What do you suppose is the reason and what do you need to do.
Answer:
The reaction is endothermic
Increase temperature of the flask
Explanation:
Sublimation is a phenomenon in which a substance changes directly from solid to gas,without passing through the liquid phase.
Camphor is a sublime substance. The sublimation of camphor is an endothermic reaction. This implies that energy is absorbed in the process.
For an endothermic reaction, the equilibrium position is shifted towards the right hand side by increasing the temperature of the system. Hence, if the flask is heated, more camphor will condense within a shorter time interval.
What is an atomic theory?
What is an isotope?
How is the atomic mass of an element calculated?
Answer:
Atomic theory is the scientific theory that matter is composed of particles called atoms.
isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number.
to calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons.
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Explanation:
1.) Electromagnetic waves that you can see are called:
A) Ultraviolet rays
B) microwaves
C) visible light
D) infrared rays
2.) These waves have the longest wavelength and the lowest frequency.
A) infrared waves
B) radio waves
C) microwaves
D) gamma rays
3.) Which wave has high enough energy to cause damage to skin and sometimes cancer?
A) Ultraviolet rays
B) microwaves
C) visible light
D) infrared rays
4.) Waves with high frequency have a ___________ wavelength
5.)Electromagnetic waves are _________ waves, the energy of the wave moves at right angles to the direction of travel.
6.) Which type of wave travels faster in a vacuum: visible light or radio waves? Explain your answer.
7.) What Electromagnetic wave has the highest frequency? What does that mean about the energy of this type of wave?
8.) Mechanical waves like sound require a medium to travel. Are electromagnetic waves mechanical waves? Why or Why not?
9.) Identify each type of electromagnetic wave from the illustration.
(The photo comes with this question)
A solution that has a pH of 5
Answer:
don't you have any options
A paint bucket is cheaper than a zinc (galvanized) iron bucket. Which bucket would you buy as a science learning student? Give reasons.
Urgent!!!!!
Answer:
[tex]zinc \: (galvanized) \: iron \: bucket.[/tex]
How did Thomson's experiment change Dalton's atomic model?
A. Thomson discovered that atoms changed properties when put in
an electric field.
B. Thomson discovered that atoms did not rearrange when forming
compounds.
C. Thomson discovered that atoms of one kind of element could
have different masses.
D. Thomson discovered that the atom contained smaller particles
called electrons.
Answer:
D. thomson discovered that the atom contains smaller particles called electrons
Thomson discovered that the atom contained smaller particles called electrons. The correct option is D.
What is Dalton's atomic model?Dalton proposed that all matter is composed of tiny indivisible particles known as atoms, which he envisioned as "solid, massy, hard, impenetrable, movable particle(s)."
Thomson's experiment altered Dalton's atomic model by revealing the existence of smaller particles known as electrons within the atom.
The first part of his theory states that all matter is made up of indivisible atoms. According to the second part of the theory, all atoms of a given element have the same mass and properties.
One of Dalton's most important contributions is that it does not violate several fundamental laws of chemical combination, including the law of definite proportions, the law of multiple proportions, and the law of conservation of mass.
Thus, the correct option is D.
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what turns colour in an acid and base
Answer:
Chemists use a solution called Universal Indicator to identify acids and bases. ... The Universal Indicator Color Guide shows that Universal Indicator turns red when it is added to a strong acid, it turns purple when it is added to a strong base, and it turns a yellowish-green when it is added to a neutral solution.
Explanation:
Answer:
Phenolphthalein
Explanation:
How many atoms are present in 7.50 mol of chlorine atoms? _
Answer:
4.52 x 10²⁴ atoms Cl
Explanation:
A mole is a name that means a certain number like a dozen means 12. 1 mole of chlorine atoms is 6.022 x 10²³ chlorine atoms. The unit conversion is 6.022 x 10²³/mol.
[tex]7.50molCl*\frac{6.022 x 10^{23} atomsCl}{1molCl} = 4.5165*10^{24} atomsCl[/tex]
Round to 4.52 x 10²⁴ atoms Cl for the correct number significant figures.
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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Describe the specific steps a scientist would take to solve a particular problem
Answer:
scientific method
Explanation:
- make an observation
- ask a question
- form a hypothesis
- make a prediction based on the hypothesis
- test the prediction
- iterate: use the results to make new hypotheses or predictions