Answer:
Hydrogen is the first element in the periodic table. Oxygen is the eighth element in the periodic table.
Both elements are gases.
Hydrogen is used for the Haber process and rocket fuel.
Oxygen is used for breathing and production purposes.
Air composes 21% oxygen and 0.0001% hydrogen.
Water is an example that contains both hydrogen H2 and oxygen O2 molecules.
Answer:
Hydrogen is the chemical element with the Symbol H and atomic number 1.
Hydrogen is the lightest element in the periodic table and it is the most abundant in the universe.
WHILE:
Oxygen is the chemical element with the symbol O and the atomic number 8.
It is a member of the chalcogen group in the periodic table.
This is what we humans take in to breathe that gives us life.
How much energy does a 185 nm wave of light have? (The speed of light in a
vacuum is 3.00 x 108 m/s, and Planck's constant is 6.626 x 10-34 Jos.)
A. 1.07 x 10-18 J
B. 8.38 x 1034j
C. 9.31 x 1017 J
D. 3.68 x 10-32 J
O
Answer: A. 1.07 x 10∧ -18 J
Explanation:
The energy can be calculated by using this relation; E = hc / ∧
Where E = energy
h = Planck's constant = 6.626 x 10-34joules
c = speed of light = 3.00 x 10∧8 m/s
∧ = wavelenght = 185 nm = 185 x 10∧ -9m
Therefore; E= hc / ∧
= (6.626 x 10-34 j/s) x ( 3.00 x 10∧8 m/s) / 185 x 10∧ -9m
= 1.987 x 10 ∧ -25 / 185 x 10∧ -9m
= 1.07 x 10∧ -18 J
What is Kb for CH3NH2(aq) + H2O(1) CH3NH3(aq) + OH (aq)?
Answer:
Option B.
Kb = [CH3NH3+] [OH-] / [CH3NH2]
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
CH3NH2(aq) + H2O(l) <=> CH3NH3+(aq) + OH- (aq)?
The expression for the equilibrium constant, Kb is simply the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.
Thus, the expression for the equilibrium constant, Kb fo th above reaction can be written as follow:
Kb = [CH3NH3+] [OH-] / [CH3NH2]
Option B gives the correct expression for Kb.
Answer:b
Explanation:AP EX
Monica has $20. She needs to buy a gallon of milk that costs $2.50. She also wants to buy yogurt, which costs $1.20 a cup. What is the greatest number of cups of yogurt Monica can buy? Use the inequality 1.20x + 2.5 ≤ 20 to solve the problem
What was the purpose of the periodic table?
A. To organize elements as they were discovered
O B. To list the chemical reactions an element can have
O C. To name elements as they were discovered
O D. To identify all the isotopes of each element
SUBMIT
Answer:
A
Explanation:
The purpose of the periodic table was to organize elements as they were discovered into periods and groups, according to their properties. It was not just a naming of elements, as a list.
The purpose of the periodic table was to organize elements as they were discovered. Thus option A is correct.
What is periodic table?Periodic table is defined as an arrangement of all known elements in order of increasing atomic number and recurrent chemical attributes.
It can also be defined as a tabular arrangement of chemical elements ordered by increasing atomic number and element groups.
It helps us to learn about an ordered grouping of the 118 known chemical elements.
The periodic table contains alkali metal, alkaline earth metal, transition elements, noble gas, post transition element etc. and many more elements are arranged in periodic table in groups.
Thus, the purpose of the periodic table was to organize elements as they were discovered. Thus option A is correct.
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(PLEASE HELP, LAST QUESTION I NEED! ) Describe to me the purpose of stoichiometry calculations.
Explanation:
Stoichiometry measures these quantitative relationships, and is used to determine the amount of products and reactants that are produced or needed in a given reaction. Describing the quantitative relationships among substances as they participate in chemical reactions is known as reaction stoichiometry.
Need help ASAP!!!! what is the value (angle) for the C=C=O bond in Ketene i.e. CH2=C=O
Answer:
[tex]180^\circ[/tex] by the VSEPR theory.
Explanation:
This question is asking for the bond angle of the [tex]\rm C=C=O[/tex] bond in [tex]\rm H_2C=C=O[/tex]. The VSEPR (valence shell electron pair repulsion) theory could help. Start by considering: how many electron domains are there on the carbon atom between these two bond?
Note that "electron domains" refer to covalent bonds and lone pairs collectively.
Each nonbonding pair (lone pair) of valence electrons counts as one electron domain.Each covalent bond (single bond, double bond, or triple bond) counts as exactly one electron domain.For example, in [tex]\rm H_2C=C=O[/tex], the carbon atom at the center of that [tex]\rm C=C=O[/tex] bond has two electron domains:
This carbon atom has two double bonds: one [tex]\rm C=C[/tex] bond and one [tex]\rm C=O[/tex] bond. Even though these are both double bonds, in VSEPR theory, each of them count only as one electron domain. Keep in mind that there are only four valence electrons in each carbon atom. It can be shown that all four valence electrons of this carbon atom are involved in bonding (two in each of the two double bonds.) Hence, there would be no nonbonding pair around this atom.In VSEPR theory, electron domains around an atom repel each other. As a result, they would spread out (in three dimensions) as far away from each other as possible. When there are only two electron domains around an atom, the two electron domains would form a straight line- with one domain on each side of the central atom. (To visualize, consider the three atoms in this [tex]\rm C=C=O[/tex] bond as three spheres on a stick. The central [tex]\rm C[/tex] atom would be between the other [tex]\rm C[/tex] atom and the [tex]\rm O[/tex] atom.)
This linear geometry corresponds to a bond angle of [tex]180^\circ[/tex].
Select the most dilute solution a.A solution made by dissolving 60g of sodium hydroxide in 2000cm cubed b.A solution made by dissolving 40 g of sodium hydroxide in 1000 cm cubed of solution. c.A solution made by dissolving 10 g of sodium hydroxide in 250 cm cubed of solution. d.A solution made by dissolving 20 g of sodium hydroxide in 500 cm3 of solution.
Answer:
A, a solution made by dissolving 60g of sodium hydroxide in 2000cm³
Explanation:
Concentration = no. of moles / volume (in dm³)
1 dm³ = 1000cm³
no. of moles = mass / molar mass
molar mass of NaOH = 23.0+16.0+1.0 = 40 g/mol
Let's find the concentration of each of the solutions:
A:
= 60/40 /2
= 0.75 mol/dm³
B:
= 40/40 /1
= 1 mol/dm³
C:
= 10/40 / 0.25
=1 mol/dm³
D:
= 20/40 / 0.5
= 1 mol/dm³
Since 0.75mol/dm³ is the lowest concentration out of 4, it is the most dilute.
A bauxite mining company has got government permission to acquire agricultural land in a location to start surface mining activities. Which of these is the best plan to solve the problem of permanent dislocation of farmers due to mining in the location?
Answer:
make reclamation compulsory after bauxite has been removed
Explanation:
Available options:
choose other infertile and uninhabited locations for bauxite mining
allow agriculture and mining to take place simultaneously in the location
ask farmers in the location to help in mining bauxite
make reclamation compulsory after bauxite has been removed
The correct option and the best plan to solve the problem of permanent dislocation of farmers would be to make reclamation compulsory after the bauxite has been removed.
Reclamation would involve restoring the agricultural land back to its original status prior to the commencement of bauxite mining. By doing this, the farmers can return to their farmland after being temporarily displaced due to the mining activities.
answer is b
please mark brainliest
A drug problem can quickly consume A)a small portions of a person income B)the bulk of a person income C)a person excess income
Answer:
b
Explanation:
a drug problem consumes the bulk of a persons income because drugs are expensive to buy
A drug problem can quickly consume the bulk of a person income
What is a drug problem?A drug is any chemical substance that causes a change in an organism's physiology or psychology when consumed. Drug abuse or substance abuse refers to the use of certain chemicals for the purpose of creating pleasurable effects on the brain.
Drug use can have significant and damaging short-term and long-term effects. Taking some drugs can be particularly risky, especially if you take high doses or combine them with other drugs or alcohol.
People of any age, sex or economic status can become addicted to a drug. Certain factors can affect the likelihood and speed of developing an addiction.
The best way to prevent an addiction to a drug is not to take the drug at all. If your doctor prescribes a drug with the potential for addiction, use care when taking the drug and follow the instructions provided by your doctor. Thus you can save your income.
The correct answer is option B.
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I need a help from this question!!
Answer:
B
Explanation:
Please take a look at the picture attached for the drawings and structures.
C2H4 is a alkene (C-C double bond). When steam (water) is added, it turns into an alcohol, where the double bond breaks and a (-OH) functional group is attached to one of the Carbons. In this case, C2H4 ethene is turned into ethanol.
When an alcohol undergoes oxidation, primary alcohols turn into aldehyde (-CHO) or carboxylic acids (-COOH). Secondary alcohol turns into ketone. Ethanol is a primary alcohol. And since it later reacts with propanol, it can only form carboxylic acid when it oxidizes. The product in this reaction is ethanoic acid.
Carboxylic acid reacts with alcohol to form an ester (-COO-). the -COOH group from acid combines with the -OH group from alcohol to form an ester bond -COO- while eliminating H2O. Therefore, when propanol undergoes esterification with ethanoic acid, propyl ethanoate is produced. It is the answer of B.
what happens to the concentration of a product over the course of a reaction
Answer:
it becomes poisonous to the body
Modern atomic theory states that atoms are neutral. How is this neutrality achieved? (3 points) Select one: a. Equal number of neutrons and protons b. Equal number of protons and electrons c. More electrons than protons d. More neutrons than electrons
Answer:
The answer is option B.
Equal number of protons and electronsHope this helps you
Answer:
equal number of electrons and protons
Explanation:
electron is negatively charged and proton is positively charged for an atom to stay neutrality # of electrons and protons must be equal.
Which group will have a charge of +2 when ionized?
O A. Alkali Earth metals
OB. Halogens
C. Alkali metals
D. Noble gases
Answer:
Alkaline earth metals
Explanation:
Group 2 has 2 valence electrons that they lose when being ionized, thus making their charge 2+.
Answer:
alkali earth metals
Explanation:
ed tell chem
How do you find the amount of electrons for any element?
Answer:
If you know the number of protons and neutrons you have to simply subtract the number of neutrons by number of protons the answer will be number of neutron
Explanation:
Answer:
We can find the amount of electrons through its Atomic number and with the help of electronic configuration
Which of the following is a characteristic property of the halogen? A. They are very reactive B. They are very stable C. They are metals D. They are all gases
Answer:A
Explanation:
They are very reactive is a characteristic property of halogen.
Hence, Option (A) is correct answer.
What is Halogen ?Halogens are non metallic elements in periodic table. It belongs to group 17 in the periodic table. Halogen family consists six elements that is Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At) and Tennessine (Ts).
What are the characteristics property of halogen ?They are nonmetals. Halogens have 7 valence electrons. They are highly reactive with alkaline earth metal and alkali metals. Halogens are not stable.Thus, from the above conclusion we can say that They are very reactive is a characteristic property of halogen.
Hence, Option (A) is correct answer.
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An open flask sitting in a lab refrigerator looks empty, but it is actually filled with a mixture of gases called air. If the flask volume is 4.00 L, and the air is at standard temperature and pressure, how many gaseous molecules does the flask contain
Answer: [tex]1.07\times 10^{23}[/tex] molecules
Explanation:
According to the ideal gas equation:
PV=nRT
P = Pressure of the gas = 1 atm ( at STP)
V= Volume of the gas = 4.00 L
T= Temperature of the gas in kelvin = 273 K ( at STP)
R= Gas constant = 0.0821Latm/kmol
n= moles of gas= ?
Putting in the values we get:
[tex]1atm\times 4.00L=n\times 0.0821Latm/Kmol\times 273K[/tex]
[tex]n=0.178mol[/tex]
Now 1 mole of any substance contains [tex]6.023\times 10^{23}[/tex] molecules at STP
Thus 0.178 mole of any substance contains = [tex]\frac{6.023\times 10^{23}}{1}\times 0.178=1.07\times 10^{23}[/tex] molecules at STP
Thus there are [tex]1.07\times 10^{23}[/tex] gaseous molecules in the flask.
first ionization energy
Answer:
The first ionization energy is defined as
Energy which is required to pull out one mole of the outermost shell's electrons in a neutral atom from one mole of gaseous atoms to produce 1 mole of gaseous ions each with a charge of 1+.[tex]A\to A^++ e^{-}[/tex] , where A is any neutral atom.In the periodic table, Its value decreases from top to bottom in groups and increases from left to right across a particular period. Helium has the largest first ionization energy.Francium has one of the lowest.write the balanced chemical equations for the following reactions .1)Barium Chloride + Potassium Sulphate -> Barium
sulphate + potassium chloride
2].zinc+silvernitrate->zinc nitrate+silver
Answer:
1) BaCl2+K2So4 → BaSo4+ KCl
2) Zn+AgNO3 → Zn+NO3+Ag
Which are characteristics of a prokaryotic cell? Select three options. contains DNA lacks DNA contains ribosomes lacks ribosomes contains a nucleus lacks a nucleus
Answer:
Prokaryotic cells contain DNA, contain ribosomes, and lack a nucleus.
Answer:
Contains DNA
Contains Ribosomes
lacks a nucleus
Explanation: I took the quiz on edge
Research how different fossil fuels compare in terms of the amount of carbon dioxide released per kWh of energy. How much carbon dioxide is produced by burning a gallon of gasoline? A gallon of diesel?
Answer:
About 19.64 pounds of carbon dioxide are produced from burning a gallon of gasoline. On the other hand, 22.38 pounds of carbon dioxide are produced from burning a gallon of diesel. So, different fossil fuels will give different amounts of carbon dioxide to be released.
Explanation:
4.Acrylic fibres are also known as
a)Terry cot
b)Orlon
c)Polyester
d)None of these
Answer:
B
Explanation:
DuPont created the first acrylic fibers in 1941 and trademarked them under the name Orlon.
PLZ HELP SUPER STUCK T^T *will give brainiest* (30 points) (plz hurry!! its on a test)
Question: Aluminum is an element. Which best describes what makes up a sample of aluminum? one kind of atom two different kinds of atoms all carbon-based atoms a carbon atom and non-carbon atoms
Answer:
The answer to this is A. One kind of atom
Explanation:
The other options make no sense whatsoever. But enjoy.
I hope this helped.
Answer:
A. One kind of atom
Explanation:
How do mass and type of material affect thermal energy transfer?
Answer:
Temperature, mass, and the type of material are factors that affect the thermal energy of an object.
Material with the higher specific heat will have more thermal energy than material with lower specific heat if they both have the same mass and temperature.
The thermal energy within the thing increases if the temperature remains constant but the object's mass rises.
If two materials have the same mass and temperature, the material with the greater specific heat will have more thermal energy than the material with the lower specific heat.
How does thermal energy transfer depend on the kind of material?
The speed at which thermal energy moves from one end of a substance to another determines thermal conductivity. Insulators transport thermal energy slowly while conductors transfer thermal energy quickly.
The thermal energy within the thing increases if the temperature remains constant but the object's mass rises.
Conduction, convection, or radiation are all ways that thermal energy can be moved from one location to another.
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When a sample of Mg is combusted in a bomb calorimeter, 25.4 kJ of energy as heat is evolved. The calorimeter contains 7.50 x 102 g of water at an initial temperature of 18.6 °C. The specific heat capacity of water is 4.184 J/gLaTeX: \cdot⋅°C and the heat capacity of the bomb is 8.20 x 102 J/°C. Calculate the final temperature of the water and the bomb
Answer:
x = 25.02 or 25°c
Explanation:
Given:
mass of water : 7.50×10² =750 gm
Ccal = 8.20× 10² = 820 J/°c
Let assume final temp = x°c
then, heat gained by the water + heat gained by calorimeter
= 25400 J
⇒ Mw × Cw× ΔTw+ Ccal ×ΔT = 25400
⇒ 750× 4.184 × (x - 18.6) + 820 ×(x-18.6) = 25400
⇒ x = 25.02 or 25°c
The proof that ch4 is a weak acid
Answer: because ch4 is not considered a acid they said it is too weak
Explanation:
help pls............
Answer:
B, 1.98g
Explanation:
No. of moles = mass / molar mass
no. of moles of Na2SO3 produced = 1.2 / 126.05 =0.009520031mol
From the balanced equation, the mole ratio of NaHSO3:Na2SO3 = 2:1, meaning every 2 moles of NaHSO3 reacted, gives out 1 mole of Na2SO3.
Since 0.009520031mol of Na2SO3 is produced, the no. of moles of NaHSO3 used = 0.009520031 x 2
= 0.019040063 mol
Mass = no. of moles x molar mass
Hence,
mass of NaHSO3 used = 0.019040063 x 104.07
= 1.98 g
= B
Name one way chemicals can help the environment
Energy storage and transport. Chemical energy transport.
Answer:
to clean the water
Explanation:
Which will change will cause the gravitational force between a baseball and a soccerball
IUPAC name for [Fe(NH3)4Cl2]NO3
Tetraamminedichloridoiron(3) nitrate
is a process that involves the collection of information and ideas supported by evidence.
Science
Systematics
Pseudoscience
Hypothesis
Answer:
pseudoscience
Explanation:
srry that this is so late btw, hope this helps...
Answer:
Science
Explanation:
First response is NOT correct