Answer:
dissolving is classified as a physical change because it can be reversed back to its original form
explanation:
Dissolving is an example of a reversible change. For example, when salt is mixed with water it disappears because it dissolves in the water to make salty water. But we can get the salt can back again by boiling off the water. That leaves the salt behind.
How do plants get their food molecules??
Answer:
Photosynthesis
Explanation:
Plants get energy/food molecules from a process called Photosynthesis
Steps Of Photosynth's -
The Reactants collect in the chloroplast. ( Carbon Dioxide, Water, Energy ) Light Energy from the sun drives Chemical Reactions.The Reactants Include glucose and oxygen which is released into the air.
Hope This Helps!
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The melting point of oxygen is -218°C and its boiling point is -183°C. What is the state of oxygen at -200°C?Immersive Reader
it is in a liquid state
Explanation:
How cold does it really get on Pluto's moon, Charon? (I know this is not a Chem question per se, but is there no Earth Science, nor Space, nor Astronomy, nor General Science category on Brainly?)
Answer:
Explanation:
After various studies and experiments conducted on Pluto's moon, Charon it has been determined that it gets to minus 459.67 degrees Fahrenheit which would be equivalent to minus 273.15 degrees Celsius. This is the coldest temperature that scientists have registered for Charon. This temperature is nearing absolute zero and puts it colder than Pluto itself since Pluto's temperature is believed to get to minus 400 degrees Fahrenheit which is equivalent to minus 240 degrees Celcius.
I need help I'll mark you as Brainliest
Answer: c
Explanation:
Which group (family) of non-metals does not form ions?
Answer:
Noble gasses
Explanation:
nobled gasses
all elements want to loose or gain electrons to be like the noble gasses in bonding but the noble gasses do not bond.
what element is 1s22s22p63s23p64s23d104p65s1
Answer:
Rubidium
Explanation:
Add the exponents: 2+2+6+2+6+2+10+6+1=37
Look for the atomic number 37
The element having electronic configuration 1s₂, 2s₂, 2p₆, 3s₂, 3p₆, 4s₂, 3d₁₀, 4p₆, 5s₁ is rubidium .
What is an element ?A chemical element is a species of atoms, including the pure substance made entirely of that species, that have a specific number of protons in their nuclei. Chemical elements, in contrast to chemical compounds, cannot be reduced by any chemical process into simpler molecules.
They can be identified by their particular atomic number. The periodic table groups the elements according to their atomic number and draws attention to those with related qualities.
The most vital ingredient for life is carbon. Life as we know it would not exist without this element. You'll see that carbon is the main component of the chemicals required for life.
Thus, The element having electronic configuration 1s₂, 2s₂, 2p₆, 3s₂, 3p₆, 4s₂, 3d₁₀, 4p₆, 5s₁ is rubidium .
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How does fertilizer affect nitrogen cycle
Cuando se usa demasiado fertilizante para las plantas una parte de ese nitrógeno no vuelve a la atmósfera y a cambio contamina el medio ambiente
Explanation:
the nitrogen cycle is a natural process that adds nitrogen to the soil. however the use of fertilizer has increased the amount of usable nitrogen in the soil
how can you tell if an substance is an elements
Answer:
A substance that cannot be broken down into chemically simpler components is considered an element
Hope that helps:)
A quanta of electromagnetic energy is called *
Answer: A quantum of electromagnetic energy is called a photon. Also, do you mean a quantum because I don't think a quanta is a thing
Explanation:
Anyone know how to do this?
Answer:I can’t see the question
Explanation:
Which statement best compares the melting points of magnesium and sodium?
a
Magnesium has a higher melting point because it contributes one additional electron per atom than sodium in the electron sea.
b
Sodium has a higher melting point because it contributes one fewer electron per atom than magnesium in the electron sea.
c
Sodium has a higher melting point because it contributes two fewer electrons per atom than magnesium in the electron sea.
d
Magnesium has a higher melting point because it contributes two additional electrons per atom than sodium in the electron sea.
A because according to electron sea theory magnesium shares two valence electrons in electron sea while sodium shares one suggesting that magnesium has stronger metallic bond than sodium so breaking metallic bond in magnesium will require more energy as compared to breaking metallic bond in sodium
The melting point of magnesium is higher than the melting point of sodium because it contributes two additional electrons per atom than sodium in the electron sea. Thus option d is correct.
What is melting point?Melting point of a substance is the temperature at which it converts from solid state to liquid state where, the two phases are in equilibrium. Melting point is affected by the bond type, molecular weight, temperature and pressure.
Melting point of elements increases along a period because the atomic size is decreasing along the period and molecular weight is increasing. Thus, the nuclear attractive pull increases resulting in higher energy needed to break the attractive force.
Magnesium is 12th element and sodium is 11th element. Thus magnesium is smaller than sodium and have one more electron than sodium. Thus magnesium have high molecular weight and high nuclear attraction leads to its higher melting point.
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4.Which scientist described the electrons as traveling in certain orbits or energy levels?
a.Dalton
b.Rutherford
c.Thomson
d.Bohr
5.In a famous experiment, scientists bombarded a very thin gold (Au) foil with positively charged alpha particles. They found that most of the alpha particles passed right through the Au foil. However, a few of the alpha particles were deflected or bounced back toward the source. How did these scientists explain their results?
a.Negative charges are spread throughout the atom.
b.Negative charges are located in the tiny nucleus of the atom.
c.Positive charges are located in the tiny nucleus of the atom.
d.Positive charges are spread throughout the atom.
6.The atomic mass represents the weighted average of an element’s
a.Ions
b.mass numbers
c.atomic numbers
d.isotopes
7.The number of protons is represented by the element’s
a.atomic number
b.mass number
c.atomic mass
d.isotope
8.The number of protons plus neutrons is represented by the
a.atomic number
b.mass number
c.atomic mass
d.isotope
9.How many valence electrons would an atom of Chlorine have?
a.2
b.3
c.7
d.8
10.An element is found to have 2 electrons in the 3rd energy level. What is this element?
a.Boron
b.Magnesium
c.Fluorine
d.Argon
11.Which shows the order of decreasing atomic size?
a.Si, Al, Mg, Na
b.I, Br, Cl, F
c.Be, Mg, Ca, Sr
d.C, P, Se, I
12.Which of the following elements has the highest ionization energy and why?
a.Argon because it has more protons in the nucleus.
b.Argon because it has a full valence shell.
c.Chlorine because it only needs one valence electron to fill its valence shell.
d.Chlorine because it attracts electrons better.
13.Which shows the order of increasing ionization energy?
a.Si, Al, Mg, Na
b.Ga, Ge, As, Se
c.Be, Mg, Ca, Sr
d.F, Cl, Br, I
14.Identify the reason why atoms decrease in size(atomic radius)across a period on the Periodic Table.
a.Gravity pulls the electrons in towards the nucleus.
b.Increase in energy levels increases the attraction and thus pulls electron cloud in.
c.Increasing strong positive nuclear charge from the nucleus pulls in the negative electron clouds and increases with the increase in protons and electrons.
d.Electrons lose energy and collapse with an increasing number of electrons and protons.
15.What is the shielding effect?
a.The neutrons shield protons from the attraction of the electrons from the first energy level.
b.Valence electrons are shared equally between atoms.
c.The repulsion of electrons in the same energy level.
d.The inner-core electrons shield outer-core electrons from the attraction to the atom’s nucleus.
16.Which statement is an accurate description of elements from Period 3 on the periodic table?
a.It contains elements with the same number of 3 protons.
b.It contains elements with the same number of3valence electrons.
c.It contains elements with the outermost protons in the same 3rd energy level.
d.It contains elements with the outermost electrons in the same 3rd energy level.
17.The column that an element is located in tells us
a.the total number of valence electrons an atom has.
b.the total number of energy levels an atom of that element has.
c.the highest energy level an atom of that element has.
d.both b & c.
18.The Halogen family of elements all have 7 valence electrons. Which column would they be in?
a.01 (IA)
b.02 (IIA)
c.4 (IVA) or 14
d.7 (VIIA) or 17
19.The Alkali and Alkaline Earth metals belong to which columns, respectively?
a.Column IA & IIA
b.Column VIIA & Column VIIIA
c.Column IIIA & IVA
20.What do carbon and silicon have in common?
a.They belong to the same column (family), therefore they have the same number of valence electrons.
b.They belong to the same column (family), therefore they have the same number of total electrons.
c.They belong to the same column (family), therefore they have the same number of energy levels.
d.They belong to the same column (family), therefore they have the same number of protons.
21.Electromagnetic radiation can take the form of which of the following types of waves
a.Heat
b.Light
c.Ultraviolet
d.All of the above
24.In order to go to a lower energy orbit, an electron
a.Must disappear
b.Must combine with other electrons
c.Lose energy of a specific amount
d.Must be transferred to another atom
25.Please choose the correct sequence that describes the excitement of an atom.
1. Such an electron transition raises the atom from the ground state to the excited state.
2. When energy is added to an atom from an outside source, its electrons move to a higher energy level (orbit)
3. As a result, the atom emits a photon.
4. When the atom is in an excited state, the electron can drop from the higher energy level to a lower energy level.
a.1, 2, 3, 4
b.4, 3, 2, 1
c.2, 1, 4, 3
d.3, 4, 1, 2
How many atoms are in 2.54 mole O?
Answer: 1.505 * 10^24 atoms
========================================================
Work Shown:
1 mole = 6.02 * 10^23 atoms
2.5*(1 mole) = 2.5*(6.02 * 10^23 atoms)
2.5 moles = (2.5*6.02) * 10^23 atoms
2.5 moles = (15.05) * 10^23 atoms
2.5 moles = (1.505 * 10^1) * 10^23 atoms
2.5 moles = 1.505 * (10^1*10^23) atoms
2.5 moles = 1.505 * 10^(1+23) atoms
2.5 moles = 1.505 * 10^24 atoms
This is true for any element. This value is an approximation since there are roughly 6.02 * 10^23 atoms in 1 mole of any element.
5. Predict which element would have a higher electron affinity: silicon or arsenic. Support your prediction with an explanation.
Answer:
Silicone
Explanation:
According to periodic trends, electron affinity increases as you go right and decreases as you go down. Silicone is above arsenic so I would expect it to have a higher electron affinity.
1s2, 2s2, 2p6, 3s2, 3p6, 4s2
After this atom gains or loses valence electron/s, what will the oxidation number be?
Answer:
if it gains then it will be negative to whatever number it has gained and the reverse for when it loses
Explanation:
How many pounds of ice are required to absorb 4900 kJ of heat as the ice melts? The heat of fusion of water is 0.334 kJ/g.
Answer:
m = 32.34 pounds of ice.
Explanation:
In this case we need to use the following expression of heat:
q = m * ΔHf (1)
Where:
q: heat absorbed in J or kJ
m: mass of the compound in g
ΔHf: heat of fusion of the water in kJ/g
We are asked to look for the mass of ice in pounds, so after we get the grams, we need to convert the grams to pounds, using the following conversion:
1 pound --------> 453.59 g (2)
So, we have the heat and heat of fusion, from (1) let's solve for the mass, and then, using (2) the conversion to pounds:
q = m * ΔHf
m = q / ΔHf
m = 4900 / 0.334 = 14,670.66 g of ice
Now, the conversion to pounds:
m = 14,670.66 g * 1 pound/453.59 g
m = 32.34 pounds of ice.Hope this helps
Which structures join with the cell’s membrane during exocytosis?
Answer:Exocytosis is also used to integrate new proteins into the cell membrane. In this process, the new protein is formed inside the cell, and migrates to phospholipid bilayer of the vesicle. The vesicle, containing the new protein as a part of the phospholipid bilayer, fuses with the cell membrane.
Explanation:
i need help with chemistry asap. the copounds Ch3Oh and Ch3CooH react in the presence of an acid catalyst to form. A. a carboxylic B. an aldehyde C. a ketone and D. an ester.
At sea level, a kilogram welghs approximately
2 pounds
10 pounds
5 pounds
1 pound
Answer:
1 kilogram weight at sea level would be the equivalent of 2 pounds.
Explanation:
What is the boiling point of water?
A. 0°C
B. 50°C
C. 70°C
D. 100°C
Answer:
D) 100*C
Explanation:
Answer:
A. 0°C
Explanation:
El agua se evapora a los 0 grados
1. Which word has the same phoneme as grew, rude, and truth?
A. thumb
B. sure
C. look
D. scoot
Answer:
B-Sorry if this isn't right :/ Good luck.
Explanation:
Answer:
D. Scoot
Explanation:
Grew, Rude and truth all have the sound /OO/ scoot follows that pattern.
Is it okay if you help me? I'm kind of in a tight spot here. Tysmmmmmmmmmmmmm o(❁´◡`❁)o!!
Answer:
C. Remains constant
Explanation:
Hope this helps (:
mass-mass problem:
If 25.0 grams of carbon dioxide are used in photosynthesis how many grams of glucose (C6H12O6) could be Produced according
to the following equation : 6CO2 + 6H2O → C6H12O6 + 602
Answer:
17.05 g of glucose
Explanation:
The equation of the reaction is given as;
6CO2 + 6H2O → C6H12O6 + 602
From the equation;
6 mol of CO2 produces 1 mol of C6H12O6
Converting to masses;
CO2:
Mass =Number of moles * Molar mass
Mass = 6 mol * 44 g/mol = 264 g
C6H12O6:
Mass = Number of moles * Molar mass
Mass = 1 mol * 180 g/mol = 180 g
This means 264g of CO2 produces 180g of C6H12O6
25g of CO2 would produce x g of C6H12O6
264 = 180
25 = x
x = 25 * 180 / 264
x = 17.05 g
the seven continents used to be one huge supercontinent called Ppaonderosa, Panhandle, Pangaea, Panthalassa
Answer:
Pangaea
Explanation:
Answer:
Pangea
Explanation:
Pangaea or Pangea was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and it began to break apart about 175 million years ago
A chemical ____ is a force of attraction between atoms or
ions that share or transfer valence electrons.
A chemical bond is a force of attraction between atoms or ions that share or transfer valence electrons.
Why is sterilising the water rarely used in treating the sewage water?
Answer:
Sterilizing the water rarely used in treating the sewage water is described below in details.
Explanation:
Sterilization is the application of a chemical or physical system to eradicate all microorganisms, concluding comprehensive amounts of bacterial content. Heat treatment is the most relevant approach for the sterilization of waste-water that accommodates large levels of masses. well now sterilizing the water is un-usually practiced in managing the sewage water.
11. Explain Supergiants
are cool yet luminous___
because
(Circle the
correct answer.)
a. they produce more
energy
b. they are farther from
Earth
c. they are unusually large
difference between solute and solvent
When one substance dissolves into another, a solution is formed. A solution is a homogeneous mixture consisting of a solute dissolved into a solvent . The solute is the substance that is being dissolved, while the solvent is the dissolving medium. Solutions can be formed with many different types and forms of solutes and solvents.
Explanation:
solute are substance that dissolve in solvent
solvent are substance that dissolve solute
meantion the two groups of mineralsalts and their two examples (each)
Answer:
sodium example salt and soy sauce
potassium example meat milk fresh fruits
What is the symbol for Sodium?
Na
S