Cobalt-60 has a half-life of 5.20 years, which means that half the sample will be present after that time.
What is cobalt?The chemical element cobalt has the atomic number 27 and the symbol Co. It is a naturally occurring hard, glossy, silver-gray metal that is found in rocks and soils. Cobalt is magnetic when it is pure, and it can be used to make alloys, magnets, and colours. Additionally, it is employed in the manufacture of batteries, catalysis, and pharmaceuticals. The production of vitamins and proteins depends on cobalt, a trace mineral that is crucial for maintaining human health.
After 7.55 years, about 0.78 of the original 1.000 mg sample will remain.
Therefore, 0.78 x 1.000 mg = 0.780 mg will remain after 7.55 years.
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Mg + 2HCl --> MgCl2 + H2(g)
Assuming STP, how many moles of hydrogen gas did Carl and his partner collect if they collected 5. 6L?
Curious Carl and his lab partner were conducting a variety of experiments to produce gases: hydrogen, oxygen, and carbon dioxide. In one experiment, they added a piece of magnesium ribbon to 10 milliliters of hydrochloric acid. They observed bubbles being produced and did a variety of tests to identify the escaping gas; it proved to be hydrogen. The reaction is represented by the following equation.
A) 0. 250 moles
B) 2. 78 moles
C) 5. 60 moles
D) 11. 2 moles
5.60 moles of hydrogen gas did Carl and his partner collect if they collected 5. 6L.
Give a brief account on Moles ?The mole, also called Avogadro's number, is a unit of measurement used in chemistry to express the amount of matter. It is defined as the number of entities (atoms, molecules, ions, etc.) in a given sample of matter. The number of mole entities is known as Avogadro's number and is approximately 6,022 x 10²³. Moles can also be used to represent the number of units of matter in a chemical reaction. For example, the equilibrium equation for the reaction of magnesium and hydrochloric acid is Mg + 2HCl → MgCl₂ + H₂. This equation shows that for every mole of magnesium, 2 moles of hydrochloric acid are required to produce 1 mole of magnesium chloride and 1 mole of hydrogen gas.
In summary, a mole is a unit of measurement used in chemistry to describe the amount of substance. It is defined as the number of units in a particular sample of matter and is known as Avogadro's number. It can be used to convert between the mass and number of units of matter, and to describe the number of units of matter in chemical reactions.
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I need your help please...
Answer:
its c and A
Explanation:
Why are sodium ions good for making batteries?
The largest advantage of sodium-ion batteries is the high natural abundance of sodium. This could make commercial production of sodium-ion batteries less expensive than lithium-ion batteries. As of 2020, sodium ion batteries have very little share of the battery market.
The enthalpy of solution of KBr in water is about 198 kJ/mol. Nevertheless, he solubility of KBr in water is relatively high. Why does the solution process occur even though it is endothermic?
The process of dissolution of KBr in water occurs because the final solution has a lower energy state than the two components separately.
What do you mean by endothermic?
Endothermic reactions are chemical reactions that absorb energy from their surroundings in order to proceed. This energy is usually in the form of heat and is absorbed from the surroundings in order to drive the reaction forward.
Even though the dissolution process is endothermic, it occurs because the enthalpy of solution is less than the sum of the enthalpies of the two components separately. The enthalpy of solution is the energy required to break the strong ionic bonds between the KBr molecules, allowing them to dissolve into the solution. The energy released from the formation of new hydrogen bonds between the KBr molecules and the water molecules is greater than the energy needed to break the ionic bonds, resulting in a net release of energy. This release of energy causes the overall process to be exothermic, even though the dissolution of KBr into water is endothermic.
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The amount of atomic particles released by a radioactive material in a specific time is determined by strong and weak nuclear forces. strong and weak gravitational forces. attraction and repulsion caused by electric forces. attraction and repulsion caused by magnetic forces.
The amount of atomic particles released by a radioactive material in a specific time is determined by strong and weak nuclear forces option- 1 is correct.
What exactly do you mean by radioactive materials?Radioactive materials fall under the category of radionuclides, which are chemicals with unstable atomic nuclei. They adjust the nucleus to stabilize themselves (spontaneous fission, emission of alpha particles, or conversion of neutrons to protons or the reverse).
The amount of atomic particles released by a radioactive material over a given period of time depends on how quickly it decays.
The weak nuclear forces that exist between the nucleons of atomic particles control how quickly radioactive materials decay over time.
The nuclear forces can therefore be used to calculate the total number of atomic particles that a radioactive material releases in a given period of time (strong or weak).
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[OH-] is 5.62x10-9 56.2x10-9 O 1.78 x10-6 o 17.8 X10-9
Answer: What are you in, fudging grade two-thousand???
(HURRY) Watch the Candy Shop video. In this reaction, a student determined that the mass of the carbon product was less than the mass of the sulfuric acid and sugar that were combined. How would you account for this loss of mass? Use evidence and scientific reasoning to support your answer
The loss of mass can be accounted for by the energy released during the reaction. When the sulfuric acid and sugar mix, the reaction produces carbon dioxide gas, which has a much lower mass than the original reactants. This is because the reaction releases energy as heat, which causes the molecules to break apart and form the gaseous carbon dioxide.
What is molecule?Molecule is the smallest unit of a substance that has all the properties of that substance and is made up of two or more atoms bonded together. Molecules can either be made of elements or a combination of elements and compounds. Molecules can be described as the building blocks of matter, made up of atoms. Atoms are made up of protons, neutrons, and electrons, and the arrangement of these particles determine the type of molecule.
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At room temperature I2(s) is a molecular solid. Which of the following provides a characteristic of I2(s) with a correct explanation ?
(A) It has a high melting point because it has (B) It is hard because it forms a three-dimensional covalent network
(C)It is not a good conductor of electricity because its valence electrons are localize in bonding and nonbonding pairs. (D) It is very soluble in water because its molecules are polar.
At room temperature I₂(s) is a molecular solid. the correct explanation is : (C)It is not a good conductor of electricity because its valence electrons are localize in bonding and nonbonding pairs.
The Iodine , I₂ is the example of the molecular solid. the iodine is the good conductor of the electricity due to the valence electrons that are localized in the bonding pairs and the non bonding pairs. the iodine is the element in the periodic table with the atomic number 53. the iodine is the non metallic solid at the room temperature.
The iodine exists as the diatomic form. the each iodine molecules present as the two iodine as I₂ . this is the reason it is called as molecular solid.
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Part A
Which of the following best describes the side chain of arginine at a pH of 11?
nonpolar
uncharged but polar
charged and polar
aprotic
hydrophobic
Charged and polar is incorrect. My textbook says the pKa of the sidechain is 12.48. Can you please explain what the correct answer is?
At a pH of 11, the side chain of arginine would be positively charged (NH3+) and polar.
This is because the pKa of the guanidine group (NH2) in the side chain of arginine is 12.48, which means that at a pH greater than 12.48, the guanidine group will be protonated and carry a positive charge. Since the nitrogen atom in the guanidine group is also surrounded by hydrogen atoms, the side chain is polar.
Key points:
The side chain of arginine is a guanidine group (NH2).The pKa of the guanidine group is 12.48, which means that at a pH greater than 12.48, the guanidine group will be protonated (NH3+).When protonated, the guanidine group carries a positive charge.The nitrogen atom in the guanidine group is surrounded by hydrogen atoms, which makes the side chain polar in nature.Learn more about arginine here:
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Calculate the percentage composition (by mass) of oxygen in K2SO4.
36.72 %
18.35 %
9.18 %
23.66 %
76.34 %
Answer:
it's option no A as described in the image
How popular is hydroelectric power?
Hydroelectric power is one of the oldest and most widely used renewable sources of energy.
Globally we see that hydropower is by far the largest modern renewable source. Every country's top priority is to generate hydroelectric power so they have to rely less on nuclear and coal power plants.
Hydroelectric power is generated by using the elevation difference, created by a dam or diversion-like structure of water flowing in on one side and out, far below, on the other side.
If we talk about some countries, Hydropower currently generates 31.5% of total U.S. renewable electricity generation.
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What is the correct Lewis structure for Group 5A element, Arsenic?
.As. :AS
As
:
• As.
...
A.
B.
C.
D.
A.
A
B.
B
C.
с
D. D
Answer:
As
Explanation:
because of ionic bond
SI unit is 10 times smaller than the next smallest unit. Ture or false?
Answer:
the answer is true
please mark brainlist
If the gauge pressure is 35.0 psi, and we assume the atmospheric pressure surrounding the tire is 1.00 atm, what is the total pressure of the gas in the tire
Pg denotes gauge pressure, which is related to absolute pressure as follows: Pa is the local atmospheric pressure, and pg is equal to p - pa.
An automobile tire gauge, for instance, reads 32.0 psi. 14.2 psi is the atmospheric pressure in the area. The gauge pressure equation states that gauge pressure equals the difference between absolute pressure and atmospheric pressure: P G = P P A, or PG=PPA. A tire pressure gauge, for example, monitors the pressure in the tire above ambient pressure. Gauge pressure is the pressure in particular items. Thus, gauge pressure plus atmospheric pressure add up to the total pressure, or absolute pressure: Pabs=Pg+Patm Pabs is the absolute pressure, Pg is the gauge pressure, and Patm is the atmospheric pressure. P abs = P g + P atm
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What element has 4 protons 6 neutrons and 4 electrons
Answer:
Beryllium is the element that is atomic number 4 on the periodic table.
A sealed, insulated calorimeter contains water at 310 K. The surrounding air temperature is 298 K, and the water inside the calorimeter remains at 310 K two hours later. What type of system does the calorimeter attempt to model
There is no heat exchange with the environment since the calorimeter is insulated. This may be demonstrated by saying: Since the calorimeter is a fixed unit, it follows that its heat capacity likewise has a fixed value.
Calorimeters are the tools used to measure the amount of heat. The definitions of heat and temperature, the quantity of heat absorbed to raise a body's temperature, the distinction between heat and temperature, and specific heat capacity are among the fundamental ideas presented in this chapter. A chemical reaction's associated thermal energy change is what causes a calorimeter's temperature to fluctuate. If the calorimeter absorbs heat (q calorimeter > 0) and its temperature rises, the reaction is producing heat (q rxn 0).
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Which of the following is incorrect:
A. Protons contribute to the mass of the atom
B. Electrons have a negative charge
c. Neutrons are found in the nucleus of the atom
d. Electrons, neutrons and protons all have the same mass
Answer: D
Explanation:
electrons have no mass
how many moles are in 4.3 grams of Cacl2
Answer:
0.038744323506090965
Explanation:
Round to whatever decimal point is needed for your answer.
Gas is collected over water at 25 °C. The pressure in the container was 0.13 atm. Using a vapor pressure chart, what is the pressure of the dry gas?
Answer:
[tex]p_{gas}=0.0987atm[/tex]
Explanation:
Hello there!
In this case, according to this problem about partial pressures, we first use the Dalton's law in order to realize how the vapor pressure of water and the partial pressure of the gas contribute to the total pressure:
[tex]P_T=p_{H_2O}+p_{gas}[/tex]
Thus, since the vapor pressure of water at 25 °C is 0.0313 atm, the partial pressure of the gas turns out to be:
[tex]p_{gas}=P_T-p_{H_2O}\\\\p_{gas}=0.13atm-0.0313atm\\\\p_{gas}=0.0987atm[/tex]
Regards!
In the reaction Cal 2 (s)+Cl 2 (g) CaCl 2 (s)+l 2 (s) , what phases are the products in after the reaction ?
A.CaCl 2 is a liquid, and l2 is a gas
B. Both products are a liquid
C. Cal2 is a solid, CaCl2 is in aqueous solution
D. Both products are solids
Answer:
D
Explanation:
because the products are CACL2 AND I2 and both are solid
What do we use a meter stick to measure?
A meterstick is used to measure things in meters and centimeters.
Meterstick is the measurement tool that measures one meter (hundred centimeters) and is used to measure the things in meters and centimeters. Metersticks are often rectangular and tin, and it is made up of wood or metal. Metal ones are often backed with a 'grippy' material such as cork, to improve the friction. Metersticks are usually divided within the lines for each millimeter (1000 per meter) and the numerical markings as per centimeter (100 per meter), with the numbers either in centi- or millimeter. It is a large ruler used for measuring the size or the distance using the metric scale.
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NO links, please! I will be reporting and reporting all of the other links you answer
Answer:
This should be correct "The biggest advantage of sexual reproduction versus asexual reproduction is genetic diversity. When a single organism reproduces asexually it produces an exact copy of the parent organism."
Explanation:
sorry that I'm late but brainliest ....... please...................., maybe............... ?????
what happens to the speed of a sound wave from an underwater animal as the sound passes into the air above?
A. It stays the same
B. It falls to zero
C. It decreases
D. It increases
Darwin observed how farmers and breeders produced many kinds of farm animals and plants. These plants and animals had traits that were desired by the farmers and breeders. He also noticed how the study of similar body structures and vestigial organs could add to the evidence of evolution. After performing several breeding experiments, he came to certain conclusions and formulated some theories. His theory of evolution and natural selection is the most accepted one.
What is the reason behind the acceptance of Darwin's theory?
Responses
A It is based on the practical example of Lamarck’s theoryIt is based on the practical example of Lamarck’s theory
B It is supported by its harmonizing with other views.It is supported by its harmonizing with other views.
C It is based on the ideas of earlier hypothesis and laws.It is based on the ideas of earlier hypothesis and laws.
D It is supported by practical evidence and examples.
The reason behind the acceptance of Darwin's theory is D It is supported by practical evidence and examples.
What is the theory of evolution proposed by Charles Darwin?The theory of evolution proposed by Charles Darwin is a well sustained model that explains how animals change in order to adapt to an ever-changing enviroment, which is supported by scientific evidence and observations.
Therefore, with this data, we can see that the theory of evolution proposed by Charles Darwin is well sustained by evidence obtained from experimentation and also observations of the natural world.
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Slow moving gas molecules means
YALL HELP MEEE
Answer:
The gas has been cooled down
Explanation:
molecules move slower and slower and have less and less kinetic energy if you cool it down but it also has something to do with how big the particles are, how heavy they are, and their temperature. If the particles are heavier and bigger they will move slower.
And if their temperature is colder that will also cause them to move slower. Hope this helps!!
What do the small lines marked on the Meterstick represent?
The small lines marked on the Meterstick represents the measurement you make can be certain to the centimeter.
Centimeter is the metric unit of the measurement which is used for measuring the length of an object.
Meterstick is the measuring stick one meter long that is marked off in centimeters and usually millimeters. A meterstick is divided into 100 cm. The smallest lines on the meterstick are the centimeters which means that each measurement you make can be certain to the centimeter. It is used to measure the things in meters and centimeters. For example: Length of a table or the width of a bag can be measured by using a meterstick.
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Draw the product (s) formed by heating the following compounds in basic ethanol.
EtOH
NaOEt
the product (s) formed by heating the following compounds in basic ethanol: EtOH and NaOEt is shown in the image.The reaction product is simpler because it is determined by the condition of the reagent and the catalyst or solvent.
there are many factors that determine the product as given. When alcoholic beverages (beer, wine, and spirits) are diluted, ethanol is present. It is used topically to prevent skin infections, in pharmaceutical preparations (such as rubbing compounds, lotions, tonics, and colognes), cosmetics, and perfumes. Ethanol, also referred to as ethyl alcohol, is a colourless, flammable liquid with a strong odour. It is the alcohol found in alcoholic beverages and employed as a solvent that is generated by fermentation. Alcohols are organic molecules made up of carbon, oxygen, and hydrogen atoms. When two carbons are present, the alcohol is referred to as ethanol (also known as ethyl alcohol).
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What numbers do I put on the right side?
The leftovers of [tex]C_2H_2[/tex] will be 6 moles while the leftover of [tex]O_2[/tex] will be zero.
Mole ratio of reactantsIn the originally balanced equation of the reaction, 2 moles of [tex]C_2H_2[/tex] and 5 moles of [tex]O_2[/tex] react completely to produce 4 moles of [tex]CO_2[/tex] and 2 moles of [tex]H_2O[/tex]. This equation is balanced with no reactant left.
Now, 8 moles of [tex]C_2H_2[/tex] were made to react with 5 moles of [tex]O_2[/tex] in the second reaction. The mole ratio of the two reactants for complete reactions is 2:5. Thus, [tex]C_2H_2[/tex] has been supplied in excess.
Since only 5 moles of [tex]O_2[/tex] is available, only 2 moles of [tex]C_2H_2[/tex] will be consumed. Thus, 6 moles of [tex]C_2H_2[/tex] will be left while the oxygen will be completely consumed. That is, the amount of [tex]O_2[/tex] left would be zero.
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Definition of RMA in chemistry pls
Answer:
Molecule name: N--N-METHYL-N-PROP-2-YNYLAMINE
Formula: C13 H15 N
Molecular weight: 185.265 Da
RMA-3 (Rubidium Microporous Aluminosilicate-3) was hydrothermally synthesized from rubidium–aluminosilicate gels without using any organic or inorganic additives, and its structure determined by XRD Rietveld analysis was confirmed as a novel framework topology containing two 8-membered ring pore-openings with dimensions of 0.49 × 0.37 nm and 0.34 × 0.38 nm
Answer:
Hey there! Just wanted to let you know that the term RMA stands for "relative molecular mass" in chemistry. This is a measure of the size of a molecule, calculated by adding up the atomic weights of all the atoms in the molecule. For example, the relative molecular mass of water (H2O) is 18, because the atomic weight of hydrogen (H) is 1 and the atomic weight of oxygen (O) is 16. The relative molecular mass of a molecule is typically expressed in atomic mass units (amu) and can be useful for characterizing and comparing different substances, and predicting their physical and chemical properties.
About what fraction of Earth’s surface is covered by water?
A:1/4
B:1/2
C:3/4
D:9/10