Answer: They are chemically stable gases
Explanation:
Group 18 is also called the noble gases - because they have full valence shells it means they are stable and won't chemically react.
What is the energy (in joules) and the wavelength (in meters) of the line in the spectrum of hydrogen that represents the movement of an electron from Bohr orbit with n = 3 to the orbit with n = 5?
Which of the following elements has the lowest ionic radius?
Answer:Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest. So the asnwer is helium
Explanation:
A scientist was studying layers of earth in the side of a mountain. In the lower layers, she found fossils of reindeer and polar bears. In the upper layers, she found fossils of coyotes and squirrels. Which conclusion most likely explains the different fossils?
Group of answer choices
The climate was very cold in earlier time periods and became warmer in later time periods
The climate was very hot in earlier time periods and became colder in later time periods.
The climate was wet in earlier time periods and became drier in later time periods.
The climate was dry in earlier time periods and became wetter in later time periods.
Answer:
The climate was very hot and became colder in later time periods.
Answer:
The climate was very hot in earlier time periods and became colder in later time periods.
water in a plate disappear after some hour when it is kept in the sun why
Answer:
This happened because of evaporation, the sun evaporated the water.
Answer:
Because if you place the plate filled with water in the sun then a small amount of water will be dried up by the sun's heat.
Write a balanced chemical equation for the following: magnesium metal is burned in oxygen to produce magnesium oxide.
2Mg(s)+O₂(g)⇒2MgO(s)
Further explanationEqualization of chemical reactions can be done using variables. Steps in equalizing the reaction equation:
1. gives a coefficient on substances involved in the equation of reaction such as a, b, or c, etc.
2. make an equation based on the similarity of the number of atoms where the number of atoms = coefficient × index (subscript) between reactant and product
3. Select the coefficient of the substance with the most complex chemical formula equal to 1
Reaction(syntesis / combination)
Mg(s)+O₂(g)⇒MgO(s)
give coefficient
aMg(s)+bO₂(g)⇒MgO(s)
Mg, left=a, right 1⇒a=1
O,left=2b,right 1⇒2b=1,b=0.5
Mg(s)+0.5O₂(g)⇒MgO(s) x 2
2Mg(s)+O₂(g)⇒2MgO(s)
NEED ASAP PLS!!
What important contribution did Einstein make concerning the relationship between energy and matter?
a.) A small amount of matter can be changed into a huge amount of energy
b.) A small amount of energy is created when large amounts of matter is changed
c.) The creation of energy will result in matter
d.) Matter can never be created
Answer: It is a
Explanation:
Consider the reaction between 75.5 mL of 0.247 M barium hydroxide and 95.0 mL of 0.330 M HCl. Find the mole ratio of hydrochloric acid to barium hydroxide, compare to the theoretical one, and determine the limiting reactant.
Answer:
Explanation:
Ba( OH)₂ + 2HCl = BaCl₂ + 2H₂O .
75.5 mL of 0.247 M barium hydroxide = .0755 x .247 = .01864 moles
95.0 mL of 0.330 M HCl = .095 x .33 = .03135 moles
mole ratio of hydrochloric acid to barium hydroxide
= .03135 / .01864 = 1.68
theoretical ratio = 2 /1 = 2
As the theoretical ratio is more , therefore HCl is the limiting reactant .
please help question is in photo will give brainiest
Answer:
D
Explanation:
A balloon contains 3.20 L of helium. The pressure is reduced to 59.0 kPa, and the
balloon expands to occupy a volume of 5.50 L. What was the initial pressure exerted on
the balloon?
Answer:
101.4pKa
Explanation:
Given parameters:
Initial Volume of helium = 3.20L
Final pressure of helium = 59kPa
Final volume on helium gas = 5.5L
Unknown:
Initial pressure exerted on the balloon = ?
Solution;
To solve this pressure - volume problem, we simply apply the Boyle's law.
It states that "the volume of a fixed mass gas varies inversely as the pressure changes if the temperature is constant".
Mathematically;
P1 V1 = P2 V2
Now, insert parameters and solve;
P1 x 3.2 = 59 x 5.5
P1 = 101.4pKa
AYOSOMEONEHELPMEWITHTHESETWOMULTIPLECHOICEQUESTIONS
I’ll give a brainest
Answer:
b. close to 0 degree celsius
Explanation:
100 g * ( x-0)= 500 g * ( 25-x) , where x is the new temperature reached
if we solve for x , we get 20 degree celsius
i.e. the temperature of ice increases to 5 degree celsius and the temperature of water drops to 5 degree celsius
hope it helps.
Hormones are secreted by glands in the human body. The hormones control different functions of the body by targeting specific organs and controlling the way their cells work. Which organ system is made of these hormone-producing glands?
Answer:
Bb
Explanation:
When HNO3 and Au are mixed together, what do you expect to happen, and why?
No reaction, because Au is above H on the activity series and they cannot react
No reaction, because Au is lower on the activity series and cannot replace H
They form Au(NO3)2 and H2, because Au is more reactive and able to replace H
They form Au(NO3)2 and H2, because they trade places in a double replacement reaction
Answer:
B
Explanation:
There can be no reaction because Au is above H on the activity series and cannot react.
Answer: B is correct
Explanation: I took the quiz
Identify the isotope that has atoms with 28 neutrons, 23 protons, and 23 electrons
A. ^28 Ni
B. ^23 V
C. ^23 Mn
D. ^51 Sb
E. ^51 V
Answer:
E. ^51 V
Atomic number (number of protons in the nucleus): 23
Atomic symbol (on the periodic table of the elements): V
Atomic weight (average mass of the atom): 50.9415
Density: grams per cubic centimeter
Phase at room temperature: Solid
Melting point: 3,470 degrees Fahrenheit (1,910 degrees Celsius)
Boiling point: 6,165 F (3,407 C)
Number of isotopes (atoms of the same element with a different number of neutrons): 2; one stable V-51; one radioactive V-50
Most common isotopes: V-51 (99.75 percent natural abundance)
If you have a mole of boron and a mole of carbon would they have the same number of
atoms in each mole? Please help ❤️
Answer:. that contains the same number of entities as there are atoms in 12 g of carbon-12. ... the same as the mass of one mole of the compound in grams. • Skill 3-1 Calculate the ... Molar mass has units of grams per mole (g/mol). Concept 3. ... of moles to mass: •We can do the reverse with 1/M, and convert any mass in grams to.
Explanation:
The number of atoms in a mole of boron and carbon is required.
A mole of carbon and a mole of boron have the same number of atoms.
The unit of amount of substance is called mole.
[tex]1\ \text{mole}=6.022\times 10^{23}\ \text{atoms, molecules, ions, or electrons}[/tex]
So, 1 mole of any element, whether it be carbon or boron has the same number of atoms which is [tex]6.022\times 10^{23}[/tex].
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Which element rarely reacts because it has 8 electrons in its outer shell?
A. Bromine
B. Xenon
C. Arsenic
D. Potassium
Answer:
B. Xenon
Explanation:
A.P.E.X
According to the electronic configuration,the element which rarely reacts is xenon as it has 8 electrons in it's valence shell.
What is electronic configuration?Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.
Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.
Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.
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Why can a solution be classified as a mixture?
Answer:
A. It is made up of only one substance
Explanation:
Which statement best describes the physical properties of solid, liquid, and gas fuels?
-Solids and liquids decompose and transform into non-flammable vapors when exposed to their ignition point.
-The vapors produced by decomposed fuels combust into flames when heated to their flammable point.
Which statement best describes the physical properties of solid, liquid, and gas fuels? -Liquid fuels take longer to ignite than solid or gas fuels.
-Liquid fuels require the least amount of time to ignite.
Answer:
I did not understand
i donot know it is correct
(i think 2 one is the best)
Explanation:
how do i do this question please help me
Answer:
3
Explanation:
The reaction is given as:
H₂S + O₂ → SO₂ + H₂O
Let us balance the chemical equation.
We take some letters and we use them as the coefficient to balance the equation;
aH₂S + bO₂ → cSO₂ + dH₂O
Now,
Conserving H;
2a = 2d
Conserving S;
a = c
Conserving O;
2b = 2c + d
Let a = 1, d = 1, c = 1, b = [tex]\frac{3}{2}[/tex] and multiply through by 2;
a = 2, b = 3, c = 2 and d = 2
So, the balanced reaction equation is given as;
2H₂S + 3O₂ → 2SO₂ + 2H₂O
what process will decrease the level co2 in the atmosphere
Answer:planting more trees
Explanation:
Trees go through photosynthesis and uses carbon dioxide (CO2) and changes it to oxygen
Read the hypothesis below. Hypothesis: if a steel surface is wet with water, then the friction will be reduced, which question best matches the hypothesis ???
Answer:
how will water affect the force of friction
90% sure
Which of the following is a INCORRECT ionic compound formula?
MgO
Na20
MgCl
NaCl
Answer:
Na2O
explanation.
Ionic bonds refers to complete transfer of electrons from one atom to another
Why can't you squeeze a sealed plastic syringe that is completely filled with water??
Answer:
Water has less compressibility. When you squeeze it, it has no place to escape.
Explanation:
How to draw a covalent bonding plz help ppl
Explanation:
A single covalent bond is made up of 2 electrons (one from each atom). It is represented with a single line.
Each line is represented as one dot and one cross (. x)
A double covalent bond is made up of 4 electrons (2 from each atom). It is represented using 2 lines. As dot and cross, it will be represented with 2 dots and 2 crosses.
A triple covalent bond is made up of 6 electrons (3 from each atom). It is represented using 3 lines. As dot and cross, it will be represented with 3 dots and 3 crosses.
Know the number of electron (s) needed by the atom to have noble gas configuration / stable (Key: You should know your electron arrangement / group number / Refer to table provided)*.
Groups and the number of electrons needed for atoms to have noble gas configuration or have full outer shell(s).
Group 4: Four (4) electrons needed for the outer shell to become full / noble gas configuration;
Group 5: Three (3) electrons needed by the atom to have a full outer shell / noble gas configuration;
Group 6: Two (2) electrons needed
Group 7: One (1) electron needed
Which of the following instruments is a combination of a percussion and a stringed instrument?
A) saxophone
B) piano
C) oboe
D) tambourine
Answer:B
Explanation:
What level of ecological organization so all the owls in a certain area represent?
The owls in the certain area located in the picture represent a population, they are formed up as a small group of animals representing a small species.
The level of ecological organization that all owls in a given area represent is the population of owls in a given area.
What is ecology?In ecology, the organism, population, community, ecosystem, and biosphere are among the levels of organization. A population is a collection of creatures from the same species that coexist in one location and communicate with one another.
Researchers in the field of ecology focus on five major levels: organism, population, community, ecosystem, and biosphere. These levels are sometimes studied separately and other times they overlap. Let's examine each stage one by one.
The owls in the particular location shown in the image are a population; they are made up of a few individuals representing a single small species.
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What is a chemical formula?
Answer:
A chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus and minus signs.
Explanation:
what is mass in grams of 175 mL of salt water with a density of 1.30 g/cm3
Answer:
Answer: 227.5 grams
Explanation:
Answer:
227.5
Explanation:
Acellus
PLEASE, PLEASE HELP ME!!!
4 Fe + 3 02 --------------- 2 Fe2 O3
In this chemical equation, why is the number of atoms the same on each side of the arrow?
Chemical reactions reduce matter but create energy.
Chemical reactions produce new matter.
Matter cannot be created or destroyed.
Answer:
Matter cannot be created or destroyed.
Explanation:
According to law of conservation of matter, Matter can neither be created nor destroyed. It just gets converted into other forms.
So, It's important to equalize the no. of moles on either side of the chemical reaction.
[tex]\rule[225]{225}{2}[/tex]
Hope this helped!
~AnonymousHelper1807Can someone help me with this?-- 15 pts!
2H2 + O2 → 2H2O
At the beginning of the reaction, it is measured that there are 15.0 g of hydrogen (H2) and 97.0 g of oxygen (O2).
What is the theoretical yield for the water that will be produced in the reaction? (M H2O = 18.0 g/mol; M CH4 = 16.0 g/mol)
2.73 x 101 g H2O
1.34 x 102 g H2O
1.08 x 102 g H2O
5.38 x 100 g H2O
Answer:
1.08 x 10^2 gm of H2O
Explanation:
number of moles of O2 = 97g /32 g/moles = 3.03 moles
3.03 moles of O2 produces 6.06 moles of H2O
amount of water produced = 6.06 mol x 18 g /mol = 109.08 g = 1.08 x 10^2 g
Name the 3 elements, in order, that make up a very important part of Thanksgiving. (Spell out a word with chemical symbols)
Answer:
eat well, stay well, and have fun ∛π⇅πΔΔΔ≅≅⇵↑↓∫∫↑
Explanation:
Answer:
Chemical element symbols are one- and two-letter abbreviations for the element names. They are used to make the periodic table and chemical formulas easier to read. You can combine the symbols to make words. Here is a list of English words made from periodic table element symbols. There are thousands of words that can be written using these symbols, so experiment to see if you can write your name or fun messages that show your chemistry savvy.