The radioactive isotopes used in studies of metabolic pathways, this is because their location of quantity can be experimentally determined because of their radioactivity.
what is the meaning radioactive substance ?A substance is called radioactive element if it changes its atomic number or atomic weight by releasing energy, this energy present as either Alpha, beta, or gamma forms of radiation.
The alpha is a Helium nucleus, a beta particle is an electron where as gamma is high energy electromagnetic radiation, the half life can be defined as the time required by a radioactive substance to disintegrate into a different substance.
If a radioactive element has a one-hour half-life, it means that half of the element will be decayed and the remaining would decay within another hour.
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In an exothermic reaction, why does the chemical reaction give off energy in the form of heat or light? A) Energy is created in the chemical reaction. B) The reactants are more stable than the products. C) The products are more stable than the reactants. D) The reactants have less energy stored in the bonds than the reactants.
Answer:
C) The products are more stable than the reactants.
Explanation:
Exothermic reaction are reactions that dissipate energy to the environment. In exothermic reactions the reactant are at higher energy than the product therefore they release more heat to the surroundings. The ability and haste for exothermic reaction to go into reaction and release heat contributes to the stability of the product than the reactant .
Example of Exothermic reactions includes the combustion of methane ;
CH4(methane) + 2O2(oxygen molecule) → CO2(carbon dioxide) + 2H2O(water molecule) + heats
The reactant is at the left hand side while the product is at the right.
Which statement is the best example of pseudoscience?
A. Mike joined a group that studies phrenology.
B. C.J. joined a group that studies endangered species.
C. Katarina joined a group that studies herbal remedies.
D. Lee joined a group that studies stars and planets.
The correct answer is A. Mike joined a group that studies phrenology.
Explanation:
In science, a "pseudoscience" refers to practices and believes that have been claimed scientific but have not been proved or do not follow the scientific method to be considered as real science. Because of this pseudosciences are mainly considered as invalid and are not officially recognized by science. An example of this is astrology as this states the movements of celestial bodies influence human and life and therefore can be used for prediction. Considering this, the statement that is an example of pseudoscience is "Mike joined a group that studies phrenology" because phrenology is a set of beliefs and practices that focus on measuring the skull to determine mental abilities, issues, etc but this was never proved through the scientific method and therefore nowadays is just a pseudoscience.
when using the celestial coordinate system,which of the following is not true?
a) All of the stars can be observed from any location on Earth.
b) Most of the stars appear to rise to the right in the sky at night.
c) Many stars, planets, and comets can be located.
d) All of the 88 constellations can be located.
When using the celestial coordinate system, all of the stars can be observed from any location on Earth is not true. Hence option A is correct.
What is celestial coordinate system?Celestial coordinate system is defined as the structured ways to specify the positions of satellites, planets, stars, galaxies, and other celestial objects with relation to the physical reference points that an observer in a particular location may access. The horizon system (altitude and azimuth), galactic coordinates, and the ecliptic system are employed as coordinate systems.
The advantage of using this set of numbers is that you can see the sky turn by roughly one hour's worth of right ascension for every hour of time as the Earth revolves. This makes predicting when celestial objects will appear and disappear easier. The positions of objects on the celestial sphere are defined using a reference system called celestial coordinate.
Thus, when using the celestial coordinate system, all of the stars can be observed from any location on Earth is not true. Hence option A is correct.
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which statement explains why neon is a group 18 element
Elements in the same group/family of the periodic table are similar in what way?
a.they are all metals
b.they are all nonmetals
c.they have a full outer shell of electrons. eliminate
d.they have the same number of valence electrons.
Answer:
D. They have the same number of valence electrons
Explanation:
The periodic table arranges elements into rows known as periods and columns known as groups or families. Elements in the same group share similar chemical properties. Additionally, they have the same number of valence electrons. For example, elements in group I have one valence electrons while those in group II have two valence electrons.Elements in the same period share similar features such as having the same number of energy levels. For example elements in period 4 have four energy levels.Answer:
The Correct Answer is D
Explanation:
They have the same number of valence electrons.
A type of wood known as white pine has a density equal to 0.50 g/cm. What is the mass of a block of white pine that has the dimensions 5.0 cm by 10.0 cm by 200.0 cm ?
Which scientist developed a model of the atom that looked like a nucleus surrounded by electrons?
(select all that apply.) the elements most often found in organic molecules are _____. carbon sodium potassium hydrogen nitrogen magnesium oxygen
Organic molecules most often contain carbon, hydrogen, nitrogen, and oxygen, which are key elements forming life's essential macromolecules.
Explanation:The elements most often found in organic molecules are carbon, hydrogen, nitrogen, and oxygen. These elements are crucial for the formation of the key biological macromolecules such as carbohydrates, nucleic acids, proteins, and lipids which are fundamental to life processes. Carbon is unparalleled in its ability to form stable bonds with many elements, including itself, which leads to the immense diversity of organic compounds necessary for life. While elements like sodium, potassium, and magnesium are important to biological systems, they are not typically found in the organic molecules that make up the structures of living organisms.
What it the main difference between an ionic and a covalent bond?
Ionic bonds will be a metal + a nonmetal, and electrons are transferred from the metal to the nonmetal.
A covalent bond will be a nonmetal only. Nonmetals will not give up their electrons so electrons are shared.
I have also written this on the whiteboard in the image provided.
if 2 electrons were removed from magnesium, what would the charge on magnesium be?
After magnesium loses 2 electrons, it becomes a magnesium ion with a charge of 2+, denoted as Mg2+.
Explanation:If 2 electrons were removed from magnesium, the resulting charge on magnesium would be 2+. This occurs because magnesium is in group 2 of the periodic table and has two valence electrons. When these two electrons are removed, the magnesium atom becomes a magnesium ion (Mg2+), having two more protons than electrons, which gives it a net positive charge. In an ionic compound like magnesium chloride (MgCl2), this Mg2+ ion will typically bond with two chloride ions (Cl-), which each have a 1- charge, to achieve a neutral overall charge.
Which of these is a mixture?
A) air
B) water
C) vinegar
D) carbon dioxide
What is the chemical formula for the base lithium hydroxide?
The chemical formula for lithium hydroxide is LiOH. It is formed by the combination of lithium ion (Li⁺) and hydroxide ion (OH⁻), making it a strong base.
Chemical Formula for Lithium Hydroxide:
The chemical formula for lithium hydroxide, a base, is LiOH. Lithium hydroxide is formed by reacting lithium (Li) with water (H₂O), resulting in the liberation of hydrogen gas (H₂) and the formation of lithium hydroxide. Lithium ion (Li⁺) and hydroxide ion (OH⁻) combine to form this ionic compound.
Here are some examples of similar strong bases and their chemical formulas:
Sodium hydroxide: NaOHPotassium hydroxide: KOHCalcium hydroxide: Ca(OH)₂Strontium hydroxide: Sr(OH)₂Barium hydroxide: Ba(OH)₂The enthalpy change when a strong acid is neutralized by strong base is -56.1 kj/mol. if 135 ml of 0.450 m hi at 23.15 °c is mixed with 145 ml of 0.500 m naoh, also at 23.15 °c, what will the maximum temperature reached by the resulting solution? [assume that there is no heat loss to the container, that the specific heat of the final solution is 4.18 j/g·c, and that the density of the final solution is that of water.]
The enthalpy change is used to calculate the energy released in the reaction, which is then used to calculate the temperature rise of the solution. The final temperature of the solution after mixing of the acid and base is found to be 30.48°C.
Explanation:The enthalpy change given is the amount of energy released or absorbed per mole of acid or base that reacts. In this case, -56.1 kJ is released each time a mole of acid and base neutralizes each other. The moles of HI and NaOH are calculated as volume * molarity, giving 0.06075 mol for HI and 0.0725 mol for NaOH.
\The neutralizing reaction will exhaust the acid completely, so 0.06075 moles of acid neutralize, releasing 0.06075 mol * -56.1 kJ/mol = -3404.675 kJ of energy. This thermal energy is absorbed by the solution, raising its temperature. Assuming the solution's volume is the sum of the volumes of acid and base, its mass (in grams) is its volume * its density, giving a mass of 280 g.
Given the specific heat capacity, the increase in temperature is calculated as heat / (mass * specific heat) giving a temperature rise of 7.33°C. The final temperature of the solution is the initial temperature plus the temperature rise, so the final temperature is 23.15°C + 7.33°C = 30.48°C.
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How many grams of Cl are in 38.3 g of CHCl3?
Final answer:
There are approximately 34.16 grams of chlorine in 38.3 g of chloroform (CHCl₃), calculated by determining the molar mass of chloroform, finding the number of moles in 38.3 g, and then using the atomic mass of chlorine to find the mass of chlorine present.
Explanation:
The first step is to establish the molar mass of chloroform, which consists of 1 atom of carbon, 1 atom of hydrogen, and 3 atoms of chlorine. The atomic masses are approximately 12.01 g/mol for carbon, 1.01 g/mol for hydrogen, and 35.45 g/mol for each chlorine atom. Adding these contributions together, we find the molar mass of CHCl₃ to be:
Molar mass of CHCl₃ = 12.01 g/mol (C) + 1.01 g/mol (H) + 3 x 35.45 g/mol (Cl) = 12.01 g/mol + 1.01 g/mol + 106.35 g/mol = 119.37 g/mol.
Next, we calculate the moles of CHCl₃ in 38.3 g using the molar mass:
Moles of CHCl₃ = 38.3 g / 119.37 g/mol ≈ 0.321 moles.
Since each mole of CHCl₃ contains 3 moles of chlorine, we multiply the moles of CHCl₃ by 3 to get the moles of chlorine:
Moles of Cl = 3 x 0.321 moles ≈ 0.963 moles of Cl
Finally, to find the mass of chlorine in grams, we multiply the moles of chlorine by the atomic mass of chlorine (35.45 g/mol):
Mass of Cl = 0.963 moles x 35.45 g/mol ≈ 34.16 g of Cl.
Therefore, there are approximately 34.16 grams of chlorine in 38.3 g of CHCl₃.
Write the chemical equations showing how a buffer containing nh4cl and nh3 would neutralize added hcl and naoh (two equations).
The chemical equation of the neutralization reaction is:
[tex]NH_4Cl + NaOH \longrightarrow NaCl + NH_3 +H_2O[/tex]
What is the buffer solution?Buffer Solution can be described as a water solvent-based solution that consists of a mixture of a weak base and the conjugate acid of the weak base or a weak acid and the conjugate base of the weak acid.
They prevent a change in pH upon dilution or the addition of small amounts of acid or alkali to them.
Acid buffer possesses acidic pH and is created by mixing a weak acid and its salt with a strong base. A basic buffer contains a basic pH and is prepared from a weak base and its salt with strong acid.
When NaOH is added to the buffer containing NH₄Cl and NH₃, sodium hydroxide consumes a proton from the ammonium ion from ammonium chloride to produce NaCl, ammonia, and water.
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What does the electronegativity of an atom indicate?
The electronegativity of an atom indicates its ability to attract electrons towards itself in a chemical bond. It is a measure of the atom's tendency to gain or share electrons.
Electronegativity values range from 0 to 4, with higher values indicating a greater ability to attract electrons. Each atom has a characteristic electronegativity value associated with it. This value helps us understand how strongly an atom can attract electrons in a chemical bond.
When two atoms with different electronegativities bond together, the electron distribution in the bond becomes uneven. The atom with the higher electronegativity will pull the electrons closer to itself, creating a polar bond.
Thus, electronegativity of an atom indicates atom's tendency to gain or share electrons.
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The elements fluorine, chlorine, and iodine are all part of the same __________ on the periodic table.
Question 5 options:
A)
diagonal
B)
group
C)
period
D)
row
Based on your observations in the virtual lab, fill in the data table below. options: A:Separated using a magnet; magnetism B:Separated using filtration; conductivity C:Separated using a magnet; malleability D:Separated using a filter; magnetism
In the given observations in the virtual lab, the part of the mixture contains iron fillings which can be easily separated by using magnet. The physical property that was used to separate the iron fillings from the mixture is magnetism. Magnetism is the property possessed by magnets to attract the metal(magnetic object) towards itself or repel the magnetic objects.
In this case, the magnetic object was iron fillings and when magnet was moved over the mixture. The iron fillings got stuck to the magnet and it was easy to separate the iron fillings from the mixture. Then only mixture was left without iron fillings.
What is the final volume of a gas that initially occupies 2.50 l at and is subsequently heated to?
Is crushing a rock a chemical or physical change?
What are the three domains of the modern classification system?
Answer the answer is D
What is the name of the compound with the formula ccl 4? question 6 options: carbon tetrachloride carbon chloride tetrachlorine carbide chlorine carbide?
We are given the chemical formula which is CCl4.
C stands for Carbon while Cl stands for Chloride (chlorine in neutral form).
Since there are four Cl in the formula, hence we say tetrachloride.
Therefore the answer is:
carbon tetrachloride
Its Carbon tetra chloride. Im taking the test :)
Which of the following elements would most likely combine to form a salt
Answer:
Metallic cations from groups IA and IIA with non-metallic anions from groups VIA and VIIA.
Explanation:
Hello,
In this case, since you are not providing the elements, I'm bestowing you a strategy to predict such formation. In this case, the pair of elements most likely to form a salt are those that have a large difference in their electronegativities, it means, elements far away considering the periodic table, say metallic cations from groups IA and IIA with non-metallic anions from groups VIA and VIIA. Take into account that noble gases cannot form any compound as they do not have valence electrons. For instance, some examples are NaF, KI, CsBr and others.
Best regards.
A sample of 8.5 g nh3 on oxidation produces 4.5 g of no. calculate the percent yield. reaction: 4 nh3 5 o2 → 4 no 6 h2o
Which term below best describes a potential energy diagram in which the potential energy value of the reactants is less than that of the products? Activation energy Calorimetry Exothermic process Endothermic process
Answer:
Endothermic reaction
Explanation:
The law of conservation of energy tells us that energy cannot be destroyed nor created, it can however be changed from one form to another. When reactants take in energy, in what we call an endothermic reaction, the energy does not disappear, it is instead stored in the eventual products as potential energy. This is why the products will have more potential energy than the reactants.
The atoms or molecules in solids have no motion. true or false
Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. The given statement is true.
What is matter?Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.
Among solid, liquid and gas, solid's particle are very fixed at their mean position. The structure of solids are very compact. Particles do not move at all. There is no motion in the molecules or atoms of solid. whereas in gas and liquid particles are comparatively moveable.
Therefore, the given statement is correct.
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What makes the Group 1 elements the most reactive metals?
They have 8 valence electrons.
They have 7 valence electrons.
The have no valence electrons.
They have 1 valence electron.
Group 1 elements, also known as alkali metals, are the most reactive metals due to having 1 valence electron.
Explanation:The Group 1 elements are the most reactive metals because they have 1 valence electron. The valence electron is located in the outermost shell of an atom and is involved in chemical reactions. Since the Group 1 elements have only one valence electron, it is easier for them to lose this electron and form a positive ion, leading to their high reactivity.
You are trying to make balloon sculptures. You twist the balloons gently, but they keep popping. Besides trimming your nails, how could you you prevent that? Why will your strategy work?
Answer:
Fill the balloons with less air to decrease the pressure.
Explanation: This is what they ask you if you included in your answer afterward on Edge 2020
Answer:
I would simply remove some air from the balloons because with less air pressure the balloons will be less tight and more twistable without popping so by doing this it will be possible to sculpt the balloons into varied shapes successfully.
Explanation:
i think
Fe2o3(s)+3co(g)→2fe(s)+3co2(g) in a reaction mixture containing 189 g fe2o3 and 63.0 g co, co is the limiting reactant. part a calculate the mass of the reactant in excess (which is fe2o3) that remains after the reaction has gone to completion. express the mass with the appropriate units.
The mass of Fe₂O₃ that remains after the reaction has gone to completion is 0 grams.
Explanation:In the given reaction,
Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂(g)
Co is the limiting reactant, and Fe₂O₃ is the reactant in excess.
To calculate the mass of Fe₂O₃ remaining after the reaction, we first need to calculate the amount of Co used in the reaction:
Given mass of Co = 63.0 g
Molar mass of Co = 28.01 g/mol
moles of Co = mass / molar mass = 63.0 g / 28.01 g/mol = 2.25 mol
The molar ratio between Co and Fe₂O₃ is 3:1, which means for every 3 moles of Co, 1 mole of Fe2O3 is used. Therefore, the moles of Fe₂O₃used in the reaction is equal to (2.25 mol Co * 1 mol Fe2O3 / 3 mol Co) = 0.75 mol Fe₂O₃.
Now, we can calculate the mass of Fe2O3 remaining:
Initial mass of Fe2O3 = 189 g
moles of Fe₂O₃ used = 0.75 mol
moles of Fe₂O₃ remaining = initial moles - moles used = 0.75 mol - 0.75 mol = 0 mol
Since the moles of Fe₂O₃remaining is 0, there is no Fe₂O₃ left after the reaction has gone to completion.
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Which of following reactions shows the formation of a hydronium ion? H+ + H2O H3O+ H2O + CO2 H2CO3 NaOH Na+ + OH− H2O + NH3 OH− + NH4+
Answer : The reaction shows the formation of hydronium ion is,
[tex]H^++H_2O\rightarrow H_3O^+[/tex]
Explanation :
The given reactions are:
(1) [tex]H^++H_2O\rightarrow H_3O^+[/tex]
In this reaction, hydrogen ion react with water to give hydronium ion as a product.
(2) [tex]H_2O+CO_2\rightarrow H_2CO_3[/tex]
In this reaction, water react with carbon dioxide to give carbonic acid as a product.
(3) [tex]NaOH\rightarrow Na^++OH^-[/tex]
In this reaction, sodium dissociate to give sodium ion and hydroxide ion as a products.
(4) [tex]H_2O+NH_3\rightarrow NH_4^+[/tex]
In this reaction, water react with ammonia to give ammonium ion as a product.
From this we conclude that, only reaction 1 shows the formation of hydronium ion. While the reactions do not shows the formation of hydronium ion.