Answer:
0.25 g/cm
Explanation:
First, you multiply 10 *10 *10 and you get 1000. Then you divide it by 4000 and since 1000 is 1/4 of 4000 you get 0.25 or 1/4.
Please mark brainliest.
What charge will elements in group 2 (also identified as IIA) typically have when forming ionic compounds? Example: Magnesium (Mg, #12) (1 pt)
*
1 point
+1
+2
-1
-2
Elements in group 2 have a charge of +2 while forming ionic compounds.
While forming ionic compounds , elements of group 2 loose 2 electrons from their valence shell as a result of which charge of +2 is generated on them as electrons are negatively charged.
How does charge vary in the periodic table?As like all the other periodic trends, charge also varies across the periodic table. On moving down the group, as number of valence electrons do not change as a result of which charge too does not change along a group.
But, while moving across a period as electrons are added to the same shell the number of valence electrons no longer remains same rather it increases and so does the charge.
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Is this statement true or false?
There is nothing we can do to help prevent soil erosion. Only scientists and farmers can work on solutions.
Answer: F
Explanation:
we can prevent soil erosion by reducing the amount of water and blockages that might build water up and erode the soil around farmland/other
Where on the periodic table do you find elements that have 'full' valence electron shells and are thus stable and unreactive? (1 pt)
*
1 point
on the left side of the periodic table
on the right side of the periodic table
across the top of the periodic table
across the bottom of the periodic table
in the middle of the periodic table
scattered around the periodic table
Elements that have 'full' valence electron shells and are thus stable and unreactive are found at rightmost side of the periodic table.
What is valence electron?The electrons in an atom's outermost shell, or energy level, are called valence electrons.
For instance, the valence electrons of oxygen are six, with two in the 2s subshell and four in the 2p subshell.
The noble gases—helium, neon, argon, krypton, xenon, and radon—belong to the group (family) of elements that have complete outer shells.
Element 118, oganesson, also belongs to this group, although almost all of its chemical and physical properties are yet unknown.
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7. Complete the following table, comparing forces within atoms.
The four fundamental forces in the universe are:
Electromagnetic force
This is the force that produces electrical and magnetic effects in objectsCompared to our solar system- planets don't fall into the SunStrong Nuclear force
Attractive force between the proton and the neutron in the nuclei of atomsStrongest force known to scienceWeak Nuclear force
A force that is significant when atoms break apartIt cause the conversion of a neutron into a proton, an electron and an antineutrino.Anti-gravitational force
It is the weakest force in the universeAn unsolved mystery in scienceWhat are forces?Forces refers to any agent which causes a change in the motion or state of rest of a body.
Forces are also described as push or pull agents that change the motion or position of a body when that are applied to that body.
There are four fundamental forces in the universe and they are given below as follows:
Electromagnetic force:
This is the force that produces electrical and magnetic effects in objectsCompared to our solar system- planets don't fall into the SunStrong Nuclear force:
Attractive force between the proton and the neutron in the nuclei of atomsStrongest force known to scienceWeak force
A force that is significant when atoms break apartIt cause the conversion of a neutron into a proton, an electron and an antineutrino.Anti-gravitational force
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what safety rule does not apply to the organic chemistry laboratory? no eating, drinking, or smoking in the laboratory. wear proper clothing at all times. wear enclosed safety goggles at all times while in the laboratory. follow all safety instructions in the laboratory text or given by the teaching assistant. none of the choices are correct.
Safety rules are the regulatory actions that need to be followed to prevent any danger. Following all safety instructions in laboratory text or by assistant does not apply in an organic chemistry lab. Thus, option D is correct.
What are laboratory safety rules?Laboratory safety rules are the guidelines that are supposed to be followed by the person working in the laboratory while performing the experiments. While working in the organic chemistry lab one should never remove the equipment.
One should wear safety goggles and should not perform the experiments in absence of a teaching assistant. But it is not necessary to follow all the rules in the laboratory textbook.
Therefore, in option D. all rules of the information textbook are not necessary to be followed.
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What are the limitations of your model in explaining fusion?
The major factors influencing fusion consist of the required high temperature and high pressure which is not shown in the model and hence becomes one of its limitations.
Two major requirements for fusion are:
1) The energy from the high temperature allows the hydrogen atoms to overcome the electrical attraction between the protons. Temperatures of roughly 100 million Kelvin are necessary for fusion. Hydrogen is not a gas at these temperatures; it is a plasma. The high-energy state of matter known as plasma is one in which all atoms have had their electrons removed and are now free to move about. The sun's massive mass and the compression of that mass in the core caused by gravity allow it to reach these temperatures.
2) The hydrogen atoms are compressed together by high pressure. For Fusion, they need to be within 1x10-15 meters of one another. The sun compresses hydrogen atoms together in its core using gravity and its bulk. We must use strong magnetic fields, potent lasers, and ion beams to force hydrogen atoms together.
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Which compounds in biochemistry contain nitrogen? (Will give brainliest)
Answer:
Amino acids, nucleic acids, and nucleobases are key biological nitrogen compounds.
Explanation:
Answer:
amines and amides
Explanation:
If we are talking organic/biochemistry only I would say amines and amides
1. Blood is an example of which level of organization
Create a chart that compares physical and chemical properties. Give two examples for each type of property
Answer:
look the image
Explanation:
freon-12 is used as a refrigerant in air conditioners and as a propellant in aerosol cans. calculate the number of molecules of freon-12 in mg of freon-12. what is the mass of chlorine in mg of freon-12?
Freon-12 or dichlorodifluoromethane is a common refrigerant and propellant. 5.69 mg of Freon-12 contains 2.8 × 10¹⁹ molecules and the mass of Cl in Freon-12 is 0.94049 gm.
What is Freon-12?Freon-12 (CCl₂F₂) is a gas that was used in manufacturing propellants and refrigerants. It is a non-inflammable gas also called dichlorodifluoromethane.
Molar mass of CCl₂F₂ = 1 × 12g/mol + 2 × 35.5g/mol + 2 × 19g/mol = 121g/mol
Molecules in 5.69 mg Freon-12 are calculated as:
5.69 mg × 0.001 gm × 1 mol × 6.02 × 10²³ molecules ÷ 121 gm = 0.0002830 × 10²³ molecules = 2.8 × 10¹⁹ molecules
There are two chlorine atoms in a Freon-12 compound so the mass is calculated as:
(5.69 × 0.001 × 2) ÷ 121 = 0.94049 gm of Cl
Therefore, 0.94049 gm of Cl is present in Freon -12.
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Your question is incomplete, but most probably your full question was, that Freon-12 (CCl₂F₂) is used as a refrigerant in air conditioners and as a propellant in aerosol cans. Calculate the number of molecules of Freon-12 in 5.69 mg of Freon-12. What is the mass of chlorine in 5.69 mg of Freon-12?
17. How are the separation methods for homogeneous and heterogeneous mixtures compared?
A homogeneous mixture can be separated chemically, while a heterogeneous mixture can be separated physically.
A homogeneous mixture could be separated through distillation, while a heterogeneous mixture could be separated through filtration.
A homogeneous mixture could be separated through filtration, while a heterogeneous mixture could be separated through distillation.
A homogeneous mixture can be separated physically, while a heterogeneous mixture can be separated chemically.
The way in which the separation methods for homogeneous and heterogeneous mixtures are compared is as follows: a homogeneous mixture could be separated through distillation, while a heterogeneous mixture could be separated through filtration (option B).
What are homogeneous and heterogeneous mixtures?A homogeneous mixture is a type of mixture that is uniform throughout, and has only one phase.
A heterogeneous mixture is that which is separated into different regions or phases that have different compositions or properties.
Both homogeneous and heterogeneous mixtures can easily be separated by physical means, however, since homogeneous mixtures are even in composition, they can be separated by distillation.
Therefore, the way in which the separation methods for homogeneous and heterogeneous mixtures are compared is as follows: a homogeneous mixture could be separated through distillation, while a heterogeneous mixture could be separated through filtration.
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Answer:
A homogeneous mixture can be separated physically, while a heterogeneous mixture can be separated chemically.
Explanation:
URGENT!!! PLEASE ANSWER NOW! Which term describes the distribution of charges in a water molecule?
polar
even
negative
organic
Polar term describes the distribution of charges in a water molecule
In water molecule polar charges are seen and polar means a molecule that has a charge on one side of the molecule that is not cancelled out it has a region of partial charge one end is slightly positive and one end is slightly negative they are generally asymmetric that's why the geometry of water is bent and with an uneven distribution of the electron in the water molecule hydrogen is positive and hydroxide is negative means H⁺OH⁻ that's why water is polar molecule
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using a electron miscroscope, jane measured a rod-shaped bacterium and found it to be 0.00099345 meters in lenght. list the steps she should take to represnt this number
The transmission electron microscope (TEM) works much like a light microscope, transmitting a beam of electrons through a thin specimen and then focusing the.
What is transmission electron microscope?A stream of electrons is sent through a specimen during transmission electron microscopy (TEM), which produces a picture of the sample. The specimen is often a grid- or suspension-supported ultrathin segment that is less than 100 nm thick. As the beam passes through the specimen, a picture is created due to the interaction of the electrons with the material. The picture is subsequently enlarged and focussed onto an imaging device, such as a fluorescent screen, a sheet of photographic film, or a sensor like a scintillator linked to a charge-coupled device.
Due to the electrons' shorter de Broglie wavelength, transmission electron microscopes can image at a resolution that is substantially higher than that of light microscopes.
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question: Using an electron microscope, Jane measured a rod-shaped bacterium and found it to be 0.00000345 meters in length. List the steps she should take to represent this number in scientific notation.
Answer:
The coefficient of this value in scientific notation is 3.45.
The decimal point needs to be moved six places to the right, so the exponent is -6.
0.00000345 = 3.45 × 10-6
Explanation: edmentum sample answer
a solution of sodium bicarbonate is prepared by adding 45.00 g of sodium bicarbonate to a 1.00-l volumetric flask and adding distilled water until it reaches the 1.00-l mark. what is the concentration of sodium bicarbonate in units of (a) milligrams per liter, (b) molarity, (c) normality, and (d) milligrams per liter as caco3?
Concentration refers to the amount of substance present.
What is concentration?
The term concentration refers to the amount of substance present. There are many units that could be used for concentration of a solution. This makes reference easy.
To express the concentration in milligram per liter;
45/1000/1 L = 0.045 mg/L
To express the concentration in molarity;
Number of moles = mass/molar mass = 45.00 g /106 g/mol = 0.42 moles
Molarity = 0.42 moles/1 L = 0.42 M
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How many valence electrons makes an atom chemically unreactive? (1 pt)
*
1 point
1
7
8
11
8
Explanation:The octet rule explains reactivity in relation to valence electrons.
Valence Electrons
Firstly, let's define valence electrons. Across the periodic table, elements can have a wide range of total electrons. However, when discussing reactions, valence electrons are the most important. Electrons arrange themselves according to energy levels. Any electrons that are on the outermost energy level are considered valence electrons. Most valence energy levels, also called valence shells, hold 8 electrons.
Octet Rule
Now that we know what valence electrons are we can use them to determine reactivity. It is important to note that atoms are most stable when their valence shell is full (as supported by Hund's rule). The octet rule explains atoms will always attempt to fill their valence shell in order to become stable. If an atom has only a few valence electrons, then it will attempt to lose its electrons. On the other hand, atoms that almost have a full valence shell will attempt to gain new electrons.
The losing or gaining of electrons occurs during reactions. So, if an atom already has 8 valence electrons then it will not react. It is already stable, so it has no need to lose or gain more electrons.
Exceptions
While the octet rule explains a lot, like all rules in chemistry it has exceptions. The most common exceptions are hydrogen and helium. Due to the size of these atoms their valence shell can only hold 2 electrons. So, these atoms are actually unreactive at 2 valence electrons.
Another exception can be seen with sulfur and xenon. Both of these atoms are hypervalent. This means they can react even if they have 8 valence electrons. However, this exception is less common.
Sourav was heating oil to fry potato chips. The cooking oil all of a sudden caught fire. He took water to pour on the fire to extinguish it. But meanwhile his mother came and switched off the gas and covered the wok completely with a plate.
• Do you think pouring water to the burning oil would have worked? Why?
• Do you think what Sourav’s mother had done is right? Why?
• Can you suggest other ways in which we can stop fire due to burning
oil?
• What values of Sourav and Sourav’s mother are shown here?
what is a wire guage use for in chemis
try
Answer:
Hello How are you
Explanation: the answer might be Screenshot
Answer: Wire gauze is an essential piece of supporting equipment in a laboratory as glassware cannot be heated directly with the flame of a Bunsen burner, and requires the use of wire gauze to diffuse the heat, helping to protect the glassware.
Explanation:
What is the term for the amount of energy that needs to be added for a chemical reaction to start?.
Answer:
activation energy
Explanation:
dont really have an explanation but there's an image attached.
a chemist adds of a calcium bromide solution to a reaction flask. calculate the mass in grams of calcium bromide the chemist has added to the flask. round your answer to significant digits.
The mass of Calcium bromide added in the flask is 29.7 g.
What is Molarity?Molarity is defined as the ratio of number of moles od solute to the number of volume of solution in litres.
Molarity = number of moles/ volume
Calculation of MolesNumber of moles = Molarity × volume
Given,
Molarity of Calcium bromide = 0.363 M
Volume of Calcium bromide = 410 mL
= 0.410L
By substituting all the value, we get
Number of moles = 0.363 × 0.410
= 0.148 mol
As we know that,
Molar mass of Calcium bromide = 199.89 g
What is Mole?Mole is defined as the given mass of substance to the molar mass of substance.
Given mass = Moles × Molar mass
= 0.148 × 199.89
= 29.75 g
= 29.7 g (significant digit)
Thus, we calculated that the mass of Calcium bromide added in the flask is 29.7 g.
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DISCLAIMER:
The above question is incomplete. Below is the complete question
A chemist adds 410.0mL of a 0.363 M calcium bromide solution to a reaction flask. calculate the mass in grams of calcium bromide the chemist has added to the flask. round your answer to 3 significant digits.
Cellular respiration transforms glucose and oxygen into carbon dioxide, water, and energy. c6h12o6 6o2 → 6co2 ?h2o energy based on the law of conservation of matter, what is the missing coefficient for water?
On the basis of the law of conservation of matter, the missing coefficient for water is 6 in the process of cellular respiration. Thus, the correct option is 1.
What is cellular respiration?It is possible to define cellular respiration as a chemical process that results in the breakdown of food inside the cell and the release of ATP, which is a type of energy.
It entails the chain of chemical processes through which organic materials are oxidized to provide energy to living things.
The left side of the equation has 6 molecules. The equation must be balanced so it must be 6 for the coefficient of water.
C₆H₁₂O₆
Thus, the correct option is 1. six, 6.
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The question is incomplete. Your most probably complete question is given below:
1. 6
2. 8
3. 4
4. 2
do elements in your body occur as free elements?
Answer: The four most abundant elements in the human body – hydrogen, oxygen, carbon and nitrogen – account for more than 99 per cent of the atoms inside you. They are found throughout your body, mostly as water but also as components of biomolecules such as proteins, fats, DNA and carbohydrates.
Explanation:
Help with number 2
2. Which of the following does not describe a pure substance?
(A)
B
D
Molecules of the same type of atom attracted to each other
Molecules of different types of atoms that are not attracted each
other
Individual atoms of different types repeated to form extended
structures
Individual atoms of the same type connected to form extended
structures
Answer:
B
Explanation:
This is because due to the fact that they are not attracted to each other they do not form a solution
How do I do this equilibrium constant problem?[Ap Chem]
The equilibrium constant of the second reaction is 2.0 * 10^-3.
What is the equilibrium constant?Let us recall the the equilibrium constant shows the extent to which reactants are converted into products in a reaction. A large positive value of the equilibrium constant shows that most of the reactants is converted into products.
Now we can see that the second reaction is obtained when the first reaction is halved and inverted. This now means that we can write;
K2 = 1/K1^1/2
K2 = 1/√K1
K2 = 1/(2.5 * 10^5)
K2 = 2.0 * 10^-3
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If you have any two gases in different containers that are the same size at the same pressure and same temperature, what is true about the moles of each gas?.
When gases in two different containers are same , at same temperature, and same pressure then the number of moles must also be same.
Why the number of moles are same?See we know then if the gases with same temperature and pressure have the same number of mole then it clearly means that their volume is not same.And when we add two different gases in a same container it also turned out to be a solution because it is then a homogenous mixture.It all depends on how much amount of gas you are adding in a given container , it can be a great amount and small amount .But no matter of amount , if you add it and the amount increases then volume will definitely increase and vice-versa.To know more about mole visit:
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the diameter of a hydrogen atom is about 1.05 cross times 10 to the power of negative 10 end exponentmeters. a protein molecule has an overall length of 3000 times (or 3 cross times 10 cubed times) the diameter of a hydrogen atom
As a result, the protein molecule is 315 x 10^-9 metres long.
What does a hydrogen atom contain?The hydrogen atom is the most fundamental of all atoms because it just contains one proton and one electron.In addition to this most common isotope, the hydrogen atom can also be found in protium, deuterium, and tritium.Hydrogen, denoted by the letter H, has the first atomic number among the lightest elements.How do you describe a hydrogen atom?There are three known hydrogen isotopes.Hydrogen has isotopes with masses of 1, 2, and 3, with mass 1 being the most common.This isotope is also referred to as protium and hydrogen in everyday language (symbol H, or 1H).learn more about hydrogen atom here
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H2(g) + Br2(g) → 2HBr(g)
The above reaction is carried out at 25oC. ΔH is -72 kJ mol-1 and ΔS is - 106 J mol-1K-1, the reaction will
A. not proceed spontaneously at the given
B. proceed spontaneously at the given temperature
C. proceed in the reverse direction at the given temperature
D. proceed spontenously at lower temperature
Given the conditions for a reaction to be spontaneous under a given set of reaction conditions, the reaction not proceed spontaneously at the given temperature; option A
What are spontaneous reactions?Spontaneous reactions are reactions that proceed without an input of extra energy as the reaction favors the formation of products under the given reaction conditions.
For spontaneous reactions, free energy change, ΔG is negative and entropy ΔS is positive.
Given the above reaction occurring at the given conditions:
H₂ (g) + Br₂ (g) → 2 HBr(g)
The reaction was carried out at 25 °C.
ΔH is -72 kJmol⁻¹ and ΔS = - 106 Jmol⁻¹K⁻¹
The reaction is an exothermic reaction at room temperature
The entropy, ΔS of the reaction is negative indicating that the reaction is not spontaneous at that temperature.
Therefore, correct conclusion will be that the reaction is exothermic at the given temperature but will not proceed spontaneously under the given conditions.
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In the bicarbonate buffering system, carbon dioxide and water join to form ___________, which dissociates into hydrogen and ________________.
In the bicarbonate buffering system, carbon dioxide and water join to form carbonic acid, which dissociates into hydrogen and bicarbonate.
Why bicarbonate is an excellent buffering system?Bicarbonate is an excellent buffering system because this compound can bind free hydrogen ions (H+) and thus the system avoids sudden changes in the pH of a solution.
In conclusion, in the bicarbonate buffering system, carbon dioxide and water join to form carbonic acid, which dissociates into hydrogen and bicarbonate.
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helium has a molecular weight of 4.003. what is the weight of 2 cubic meters of helium at 1 atmosphere and 20°c?
Helium has a molecular weight of 4.003. The weight of 2 cubic meters of helium at 1 atmosphere and 20°c is 3.27 N.
What is helium?Helium is the second element in the periodic table. It is the lightest gas present in the atmosphere.
By the law of pure gas.
PV = nRT
The initial pressure is p = 101. 325 Kpa
Initial volume, v = 2 m
The molecular weight of helium is, 4.003
Initial temperature, T = 20°c, = 293 K
Universal gas constant is R = 8.314\ \rm{kJ/kg-K}
Putting the value in the formula
PV = mRT / M
m = 101. 325 Kpa x 2 x 4.003 / 8.314 x 293 = 0.333 kg.
The weight of helium gas
W = mg
0.333 x 9.81 = 3.27 N
Thus, the weight of 2 cubic meters of helium is 3.27 N.
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Can someone please help me write a poem about scientific law vs scientific theory?
what ratio of ch₃nh₂ to ch₃nh₃⁺ is needed to prepare a ph 10.30 buffer? (kb for ch₃nh₂ is 4.4 × 10⁻⁴)
ratio of CH3NH2 to CH3NH2+ is 2.58:1
The acid dissociation constant, Ka, of acids and bases, and the pH of a chemical solution of a weak acid are related by the Henderson-Hasselbalch equation.A weak acid and the conjugate base of the weak acid, or a weak base and the conjugate acid of the weak base, are combined to form the buffer solution, a water-based solvent solution.Use the Henderson Hasselbalch equation pH = pKa + log [salt]/[acid]
first solve for [salt]/[acid]
pKb= -log Kb= 7.72
10.30= 7.72 + log [salt]/[acid]
log [salt]/[acid] = 2.58
[salt]/[acid] = 2.58
So you need 2.58 : 1 for the ratio of CH3NH2 to CH3NH3^+
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