Answer: An electron is a particle with a negative charge, found outside the nucleus.
Explanation: In an atom, there is a nucleus in the center that has protons and neutrons. Mostly the mass of an atom is the sum of masses of protons and neutrons. Protons are positively charged ions and neutrons are neutral.
Electrons are present around the nucleus(outside the nucleus) in different energy shells. An electron has negative charge and gain or loss of electrons is the cause of chemical reactions.
Number of protons equals to the atomic number of an atom. Number of electrons is also same to the number of protons for a neutral atom where as the difference of mass number and protons is the number of neutrons.
An electron is a particle with a negative charge, found outside the nucleus and the correct option is option 2.
An electron is a negatively charged subatomic particle that can be either bound to an atom or free (not bound). An electron that is bound to an atom is one of the three primary types of particles within the nucleus of an atom -- the other two are protons and neutrons.
The structure and quantity of electrons in an atom dictate the specific energy levels or orbitals that the electrons inhabit. There can be up to two electrons in the first electron shell, and there can be up to eight electrons in each of the second and third electron shells.
An atom's reactivity and chemical characteristics are governed by the number of electrons in its outermost shell.
Thus, the ideal selection is option 2.
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Which of the following are not grouped according to similar chemical properties?
A. Cobalt, iron, nickel.
B. Iron, copper, ruthenium.
C. Ruthenium, iridium, palladium.
D. Gold, silver, copper.
B. iron, copper, ruthenium
Answer: The correct answer is Option D.
Explanation:
Elements which belong to same group show similar chemical properties because they have same number of valence electrons.
From the given options:
Option A: Cobalt belongs to Group 9, Iron belongs to Group 8 and Nickel belongs to Group 10. Hence, they will not show similar chemical properties.
Option B: Iron belongs to Group 8, Copper belongs to Group 11 and Ruthenium belongs to Group 8. Hence, they will not show similar chemical properties.
Option C: Ruthenium belongs to Group 8, Iridium belongs to Group 9 and Palladium belongs to Group 10. Hence, they will not show similar chemical properties.
Option D: Gold, Silver and Copper belongs to the same group which is Group 11. Hence, they all will show similar chemical properties.
Thus, the correct answer is Option D.
Which reactions are oxidation-reduction reactions?
1. FeS(s) + 2HCl(aq) → H2S(g) + FeCl2(g)
2. AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3
3. 2C3H6(g) + 9O2(g) → 6CO2(g) + 6H2O(g)
4. Fe2O3(s) + 3CO(g) → 2Fe(l) + 3CO2(g)
Answer: The correct answer is Option 3 and Option 4.
Explanation:
Redox reactions are termed as the reactions in which reduction and oxidation reactions occur simultaneously.
Reduction reactions are the ones where a substance gains electrons. The oxidation state of the substance gets reduced.
Oxidation reactions are the ones where a substance looses electrons. The oxidation state of the substance is increased.
Fro the given options:
Option 1: [tex]FeS(s)+2HCl(aq.)\rightarrow H_2S(g)+FeCl_2(g)[/tex]
This reaction is a type of double displacement reaction because exchange of ions takes place.
Option 2: [tex]AgNO_3(aq.)+NaCl(aq.)\rightarrow AgCl(s)+NaNO_3[/tex]
This reaction is a type of double displacement reaction because exchange of ions takes place.
Option 3: [tex]2C_3H_6(g)+9O_2(g)\rightarrow 6CO_2(g)+6H_2O(g)[/tex]
On reactant side:
Oxidation state of Carbon = +2
Oxidation state of Oxygen = 0
On product side:
Oxidation state of Carbon = +4
Oxidation state of Oxygen = -2
Here, oxidation state of carbon is increasing from +2 to +4. Thus, it is getting oxidized and oxidation state of oxygen is getting reduced from 0 to -2. Thus, it is getting reduced.
Option 4: [tex]Fe_2O_3(s)+3CO(g)\rightarrow 2Fe(l)+3CO_2(g)[/tex]
On reactant side:
Oxidation state of Iron = +3
Oxidation state of Carbon = +2
On product side:
Oxidation state of Iron = 0
Oxidation state of Carbon = +4
Here, oxidation state of carbon is increasing from +2 to +4. Thus, it is getting oxidized and oxidation state of iron is getting reduced from +3 to 0. Thus, it is getting reduced.
Hence, the correct answer is Option 3 and Option 4.
Scientists in ____ discover new products and processes and improve current technology.
Answer;
-Research and development
Scientists in research and development discover new products and processes and improve current technology.
Explanation;
Research scientists are responsible for designing, undertaking and analyzing information from controlled laboratory-based investigations, experiments and trials.
Additionally, research and development is an important means for achieving future growth and maintaining a relevant product in the market. Research may be basic research and applied research applied. Development is when findings of a research are utilized for the production of specific products including materials, systems and methods.
Chromium is most commonly mined in the form of chromite, which has the chemical formula fecr2o4. calculate the percent by mass of each element in chromite, and give your answers to four significant digits.
The mass of each elements in chromite is as below
Fe =24.9 %
Cr =46.5%
O = 28.6%
calculation
percent mass = atomic mass of element / atomic mass of FeCr2O4 x 100
from periodic table the atomic mass for Fe = 55.85 g/mol,
Cr =52 g/mol since they are two atoms in FeCr2O4 = 2 x 52 = 104 g/mol
for O = 16 since they are two atoms in FeCr2O4 = 16 x4 = 64 g/mol
Atomic mass for FeCr2O4 is = 55.85 +104+ 64 = 223.85 g/mol
Percent mass for Fe =55.85 /223.85 x100 = 24.9 %
for Cr = 104 / 223.85 x 100 = 46.5%
For 0 = 64/223.85 x 100 = 28.6%
The organization of hydrogen atoms around the double bond is called _____ when they are on the same side as the double bond, and _____ when they are on opposite sides of the double bond.
at 65 degrees celsius, which compound has a vapor pressure of 58 kilopascals? 1. ethanoic acid2. ethanol 3. propanone 4. water
The vapour pressure of a substance actually differs relative to the temperature. So to know which compound has the vapour pressure of 58 kilopascals at 65 degrees Celsius, we refer to standard tables of temperature vs Vapour pressure.
From the tables or graph, the answer here is:
2. ethanol
Answer: 2. Ethanol
Explanation:
The attached figure shows the relation between vapor pressure (KPa) and temperature (celsius) for the ethanoic aci, propanone, ethanol and water.Make lines by the values given of the vapor pressure (58.0 KPa) and temperature (65.0 celsius).You will find that the compound is ethanolThe mole fraction of carbon dioxide (xco2) in water is 0.25. determine the molarity of co2. (assume the density of the solution is 1.0 g/ml.)
The molarity of CO2 in a water solution with a mole fraction of 0.25, assuming the density of the solution is 1.0 g/mL, is calculated to be 0.04401 M.
Explanation:To determine the molarity of carbon dioxide (CO2) in a solution with a mole fraction (xCO2) of 0.25, and a density of 1.0 g/mL, we need to use the definition of mole fraction alongside the known density of the solution. The mole fraction is the ratio of the moles of solute to the total moles in the solution. Assuming we have one liter of solution and know that the density is 1.0 g/mL, the total mass of the solution is 1000 g.
First, we calculate the total moles of the solution. Since the mole fraction of CO2 is 0.25, this means that 25% of the moles are CO2. To find the molarity of CO2, we need to find the mass of CO2 based on its mole fraction and then convert this to moles.
Since we are given the mole fraction and we know the density of the solution, we can calculate the mass of CO2 in one liter of solution. Let's assume a total of 4 moles of substance are present (as 0.25 is one-fourth). Hence, one mole of CO2 is present because the mole fraction of CO2 is 0.25. Knowing that the molar mass of CO2 is 44.01 g/mol, we find that the mass of 1 mole of CO2 is 44.01 grams. The molarity is found by dividing the moles of CO2 by the volume of the solution in liters, which gives a molarity of 0.04401 M.
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CaCO3 is an example of which type of material?
a. colloid
b. element
c. compound
d. mixture
At standard pressure, during which physical change does the potential energy decrease?
Answer is: cooling.
Cooling is change from liquids to solids.
Another example is crystalisation, many elements and compounds form crystals.
A physical change occurs when a substance changes phase.
Physical property can be observed and measured without any changes in molecular composition. The same substance is present before and after the change.
The potential energy of a gas decreases during a phase change, such as cooling and condensing to a liquid.
Explanation:The potential energy of a gas decreases during a phase change when a large amount of energy is extracted from the system and causes a decrease in the gas's volume, pressure, or both. For example, when a gas is cooled and condenses to a liquid, its potential energy decreases. This is illustrated by a graph of pressure vs. temperature, where the pressure of a gas continually decreases as it is cooled at a constant volume.
The combustion of methane gas (ch4) forms co2(g)+ h2o(ℓ). calculate the heat produced by burning 2 mol of the methane gas. use these ∆h0 f data to help: ch4(g)= -74.9 kj/mol co2(g)= -393.5kj/mol h2o(ℓ)= -285.8kj/mol. answer in units of kj.
Final answer:
To find the heat produced by the combustion of 2 mol of methane gas, you use the standard enthalpies of formation. The calculated heat produced is -1630.6 kJ.
Explanation:
The question involves using the concept of enthalpy change (ΔH), specifically standard enthalpies of formation (ΔH°f), to calculate the heat produced during the combustion of methane gas (CH4).
Step-by-Step Calculation:
First, write down the balanced chemical equation for the combustion of methane:
CH4(g) + 2O2(g) → CO2(g) + 2H2O(№)
Next, apply Hess's Law using the provided ΔH°f values:
CH4(g): -74.9 kJ/mol
CO2(g): -393.5 kJ/mol
H2O(№): -285.8 kJ/mol
Calculate the total enthalpy change (ΔH) for the reaction:
ΔH = [1 mol(ΔH°f CO2) + 2 mol(ΔH°f H2O)] - [2 mol(ΔH°f CH4)]
ΔH = [1 mol(-393.5 kJ/mol) + 2 mol(-285.8 kJ/mol)] - [2 mol(-74.9 kJ/mol)]
ΔH = (-393.5 kJ - 2×285.8 kJ) - (-2×74.9 kJ)
ΔH = (-393.5 - 571.6 + 149.8) kJ
ΔH = -815.3 kJ
This is the enthalpy change for the combustion of 1 mol of methane. Since we are burning 2 mol of methane, multiply by 2:
Total ΔH = 2 × -815.3 kJ
Total ΔH = -1630.6 kJ
Therefore, the heat produced by burning 2 mol of methane gas is -1630.6 kJ.
Nitromethane (ch3no2) burns in air to produce significant amounts of heat. 2ch3no2(l)+3/2o2(g)→2co2(g)+3h2o(l)+n2(g) δhorxn = -1418 kj how much heat is produced by the complete reaction of 3.87 kg of nitromethane?
How do an isotope and a radioactive isotope differ?
“The maximum amount of energy that can be used to do work.” This statement describes which measure?
A.) Ecell
B.) K
C.) ∆G
D.) F
An automobile gasoline tank holds 21 kg of gasoline. when the gasoline burns, 84 kg of oxygen is consumed, and carbon dioxide and water are produced. what is the total combined mass of carbon dioxide and water that is produced?
This is as straightforward as it gets. If however you need to determine how much of each product is produced, then the balanced equation is a must.
Usually, gasoline is expressed as octane in combustion reactions, which means that the balanced equation for its combustion is
2C8H18+25O2→16CO2+18H2O
But, like I've said, for the combined mass of the products all you really need to know is the combined mass of the reactants.
Addendum
Let's say you want to know exactly how much of each compound is formed. In this case, you must check for a limiting reagent. The number of moles of octane is
21⋅103 g⋅1 mole octane114.0 g=184.2 moles
The number of moles of oxygen is
85⋅103 g⋅1 mole O232.0 g=2656 moles
According to the mole ratio between these two, each 2 moles of octane need 25 moles of oxygen, so
noxygen that reacts=noctane⋅252=2303 moles , which means that octane is the limiting reagent. The actual mass of oxygen that reacts is
2303 moles⋅32.0 g1 mole=73.7 kg
This means that the combined mass of the produced water and carbond dioxide is actually
21 kg+73.7 kg=94.7 kg
85 kg−73.7 kg=11.3 kg of oxygen will not react. If you want to count this oxygen as well, the total combined mass of the products will again be 106 kg .
In complete and ideal combustion of gasoline using the principle of conservation of mass, the total combined mass of carbon dioxide and water produced when a gasoline tank holding 21 kg of gasoline burns consuming 84 kg of oxygen is 105 kg.
Explanation:The subject of your question is based on the principle of conservation of mass, a fundamental concept in chemistry. The principle of conservation of mass states that the total mass of the reactants (the starting materials in a chemical reaction) is equal to the total mass of the products (the substances formed by the reaction). Hence, in the combustion (burning) of gasoline, the total combined mass of carbon dioxide and water that is produced would be equal to the sum of the masses of the gasoline and the oxygen consumed.
In your case, the total mass of gasoline and oxygen consumed is 21 kg (for gasoline) + 84 kg (for oxygen) = 105 kg. This means that given ideal condition and complete reaction, the total combined mass of carbon dioxide and water produced should be 105 kg.
Remember that this calculation assumes complete conversion of gasoline and oxygen into carbon dioxide and water, without production of other byproducts such as carbon monoxide and nitrogen oxides. Actual combustion processes may not be 100% efficient and may generate other byproducts.
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A catalyst increases the rate of a reaction by
A. providing an alternative reaction pathway with lower enthalpy change.
B. lowering the potential energy of the reactants in the reaction.
C. providing an alternative reaction pathway with lower activation energy.
D. lowering the potential energy of the products in the reaction.
Answer:
The correct option is C
Explanation:
For a reaction to occur, there is a minimum amount of energy that must be "met". This minimum amount of energy is called activation energy. Activation energy is the minimum amount of energy required for a reaction to occur. When this activation energy is high, it takes a longer time for the reaction to occur, hence it slows down the rate of a chemical reaction but when the activation energy is low, the rate of a chemical reaction is increased.
A catalyst is known to increase the rate of a chemical reaction - it does this by reducing the activation energy of the reaction, providing an alternative reaction pathway for the reaction.
Which topic might interest a sociologist
One light-hour is the distance that light travels in an hour. how far is this, in kilometers? ( recall that the speed of light is 300,000 km/s )
Consider a point 1 cm away from an electron with nothing else nearby. what expression could represent the electric potential at that location
suppose you want to do an experiment to hear how three different objects would sound when you dropping them the same distance. you drop a pebble a rock,and a grain of sand.what are the variables of your experiment
What must be true about electrons sharing the same atomic orbital?
A. They must have absorbed different amounts of energy.
B.They must have opposite charges.
C. One is negatively charged, the other is neutral.
D. They must have opposite spins.
Answer:
D. They must have opposite spins.
Explanation:
Two electrons in the same atomic orbital have different spins or spin number. If one electron has +1/2 spin the other electron will have -1/2 spin. In other words if one electron is spinning in the clockwise direction the other electron will be spinning in the anticlockwise direction. Two electrons in the same atomic orbital have the same principal quantum number (n), azimuthal quantum number (l) and magnetic quantum number (m).
Identify the reaction type for each generic chemical equation
A + B → AB: ✔ synthesis
AB → A + B: ✔ decomposition
Hydrocarbon + O2 → CO2 + H2O: ✔ combustion
AB + CD → AD + CB: ✔ replacement
Generic chemical equation for combination, decomposition, displacement and double displacement reactions are given as A+B=AB, AB=A+B,AB+C=AC+B and AB+CD=AC+BD respectively.
What is chemical equation?Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.
A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .
The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.
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Mendeleev noticed that certain similarities in the chemical properties of elements appeared at regular intervals when teh elements were arranged in order of increasing
Mendeleev identified the periodic nature of elements' chemical properties when arranged by increasing atomic mass, leading to the creation of the periodic table.
Mendeleev noticed that certain similarities in the chemical properties of elements appeared at regular intervals when the elements were arranged in order of increasing atomic mass. This pattern is referred to as periodic, analogous to other phenomena that occur at regular intervals, such as the swing of a pendulum or the orbit of the moon around Earth. In the construction of his periodic table, Mendeleev even listed some elements out of atomic mass order so that they would be grouped with those that had similar chemical properties, such as tellurium (Te) being placed before iodine (I) based on properties rather than atomic mass.
Dimitri Mendeleev and Lothar Meyer independently recognized the periodic relationship among the elemental properties. While Meyer arranged elements by increasing atomic mass, Mendeleev's approach distinguished him by predicting undiscovered elements like gallium and germanium, which were later found and confirmed the utility of Mendeleev's table. This foresight helped solidify the significance of Mendeleev's work on the development of the periodic table.
What information do the coefficients in a balanced chemical equation tell you
Explanation:
Coefficients are the number present in front of an atom or molecule in a chemical reaction.
For example, [tex]2Na + Cl_{2} \rightarrow 2NaCl[/tex]
In this reaction 2 in front of Na in reactant side shows 2 moles of sodium atoms are participating. Whereas 2 in front of NaCl in product side shows that 2 moles of sodium chloride is formed.
Therefore, we can conclude that coefficients in a balanced chemical equation tell you the moles of each substance involved in the reaction.
How much sulfur dioxide can be produced by the combustion of 21 tons of sulfur?
Urine, at ph 6, contains __________ h+ as household bleach, at ph 13.
How can an isotope like carbon 14 be used to date dead organisms?
What element has an electron configuration that ends in 2s2 2p4?
The oxygen element has an electronic configuration that ends with 2s²2p⁴.
What is an electronic configuration?The electron configuration can describe how electrons are arranged in different energy levels of an atom of an element. In the electron configuration of an atom, the number of electrons in a particular atomic orbital is written as a superscript. For example, the electron configuration of Helium (He) is written as 1s²2s².
The principal quantum number (n) will decide the maximum number of electrons that can be filled in a shell and is determined from the term 2n², where ‘n’ is the principal quantum number.
The atomic orbitals of an atom of a lower energy level should be completely filled before filling an atomic orbital with a higher energy level.
The atomic number of the oxygen atom is 8 and the electronic configuration is 1s²2s²2p⁴. It has six electrons in its valence shell and an electronic configuration ends with 2s²2p⁴.
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N iron chloride compound contains 55.85 grams of iron and 106.5 grams of chlorine. what is the most likely empirical formula for this compound? fecl3 fe2cl fecl fe3cl fecl2
Why do non metallic elements pull electrons from metallic elements so effectively during a reaction?
What is the error in the electron configuration, 1s2 2s2 2p6 3s2 3p5 4s2?
Final answer:
The error in the electron configuration 1s2 2s2 2p6 3s2 3p5 4s2 is that it places electrons in the 4s sublevel before filling the 3d sublevel. The correct order should fill the 3d sublevel before the 4s according to the Aufbau principle.
Explanation:
The student's question is about identifying the error in the given electron configuration, which is 1s2 2s2 2p6 3s2 3p5 4s2. The error in this configuration is the arrangement of electrons in the 4s sublevel before the 3d sublevel is filled. According to the Aufbau principle, which dictates the order in which sublevels are filled based on increasing energy, after the 3p sublevel is filled, electrons should start filling the 3d sublevel before the 4s. However, in the given configuration, it incorrectly shows two electrons in the 4s sublevel before the 3d sublevel has any electrons. The correct electron configuration after 3p6 should be 3d1 before moving to 4s1 or 4s2 depending on the element in question. For example, the correct configuration for potassium (Z=19) is 1s²2s²2p63s²3p64s¹, and for calcium (Z=20), it is 1s²2s²2p63s²3p64s².