Answer:
I'm not sure about this question but I think it C
How does the number of valence electrons in atoms of metalloids explain why metalloids are semiconductors?
A.They have one or two valence electrons, so they cannot lose electrons easily.
B.They have one or two valence electrons, so they can lose or gain electrons.
C.They have three to six valence electrons, so they cannot lose electrons easily.
D.They have three to six valence electrons, so they can lose or gain electrons.
sorry its supposed to say physics not chemistry at the top -_-
Answer:
They have three to six valence electrons, so they can lose or gain electrons.
Explanation:
just took the quiz
Metalloids are metal like elements showing intermediate properties of gases and metals. They have three to six valence electrons, so they can lose or gain electrons. That's why they are conducting.
What are metalloids?Metalloids are elements showing properties intermediate to that of metals and non-metals. They are located in the periodic table in between metals and nonmetals.
Metalloids appear as metals. They are shiny and conducting. However, their conductivity is low compared to metals and they are classified as semiconductors and they are all brittle in nature.
Boron, silicon, germanium, arsenic etc. examples of metalloids. They contains three to six valence electrons which can be delocalized or lost from the atoms.
These elements can lose electrons as well they can gain more electrons as per the bonding type. The delocalized valence electrons make them conducting. Hence option D is correct.
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Express a length of 13.63 m in centimeters.
Answer in units of cm.
Answer:
1363cm
Explanation:
1m=100cm
13.63m= 13.63•100cm
13.63m=1363cm
A high concentration of hydrogen ions means a solution is what? very basic neutral very acidic neither acidic or basic
Answer:
Very Acidic
Explanation:
I took the quiz on K12
What is the heaviest gas element
Answer:
Radon
Explanation:
n 1908 Ramsay and Gray, who named it niton, isolated the element and determined its density, finding it to be the heaviest known gas. It is essentially inert and occupies the last place in the zero group of gases in the Periodic Table. Since 1923, it has been called radon.
A steel cylinder contains 5.00 mol of graphite (pure carbon) and 5.00 mol of O2. The mixture is ignited and all the graphite reacts. Combustion produced a mixture of CO gas and CO2 gas. After the cylinder has cooled to its original temperature, it is found that the pressure in the cylinder has increased by 16.4%. Calculate the mole fractions of CO, CO2, and O2 in the final
Answer:
O₂ = 0.141
CO = 0.282
CO₂ = 0.577
Explanation:
The reaction of graphite with Oxygen is:
C(s) + O₂(g) → CO₂(g) + CO
All 5 moles of C(s) reacts producing CO₂ and CO. You can write:
5 moles = CO₂ + CO (1)
And, as pressure increased by 16.4% and initial moles of oxygen are 5.00 moles. Final moles (Moles of three gases) are:
5.00moles + 5.00moles*16.4% =
5.82 moles = O₂ + CO₂ + CO (2)
Also, there are 10 moles of oxygen in the container, that is:
10 moles = O₂*2 + CO₂*2 + CO (3)
From (2) and (1), moles of O₂ are:
O₂ = 0.82 moles
Replacing in (3)
10 mol = 0.82*2 + CO₂/2 + CO
8.36 moles = CO₂*2 + CO
5 moles = CO₂ + CO
By the sum of these equations:
3.36 moles = CO₂
And
5.0 moles - 3.36 moles = CO
1.64 moles = CO
As total moles are 5.84 moles, mole fraction of the gases is:
O₂ = 0.82 moles / 5.82mol = 0.141CO = 1.64 moles / 5.82mol = 0.282CO₂ = 3.36 moles / 5.82mol = 0.577Which of the following is a chemical property of paper? (4A)
Paper will float on water.
Paper absorbs pen ink.
Paper is white.
Paper will burn.
Answer:
D.) Paper will burn
Explanation:
The first three are physical properties of paper, but the last one is a chemical property of paper
ITS TALKING ABOUT PHOTOSYNTHESIS
Xylem helps plants deliver water and nutrients to the
entire plant. What human body system is this like?
The the two important transport tissues in plants are xylem and phloem. The human body system which is like xylem is circulatory system.
What is xylem?An important transport tissue which is found in the vascular plants along with the phloem is defined as the xylem. The major role of xylem is to transport all the essential nutrients and water to leaves and stems from the roots.
There are mainly two types of xylem, they are primary and secondary. The xylem which is found during the primary growth of the plant is called the primary xylem and the secondary xylem is found in the plant's secondary growth.
The xylem transport the substances through passive transport which does not need any external energy. The vessel elements present in the xylem are found to be similar to the blood vessels in the human body.
The blood vessels of the circulatory system carries nutrients to all the organs and removes wastes from the organs. The arteries carry blood away from the heart and veins carry blood to the heart.
Thus the blood vessels in the circulatory system is analogous to the Xylem.
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A certain compound contains 4.0 g of calcium and 7.1 g of chlorine. Its relative molecular mass is 111. Find its empirical and molecular formulas
Given :
A certain compound contains 4.0 g of calcium and 7.1 g of chlorine.
Its relative molecular mass is 111.
To Find :
Its empirical and molecular formulas.
Solution :
Moles of calcium , [tex]n_1=\dfrac{4}{40}=0.1\ moles[/tex].
Moles of chlorine , [tex]n_2=\dfrac{7.1}{35.45}=0.2\ moles[/tex] .
The ratio calcium and chlorine is 1 : 2 .
So , the empirical formula is [tex]CaCl_2[/tex] .
Now , molecular mass of [tex]CaCl_2[/tex] is :
[tex]M=40+(2\times 35.45)\\\\M=110.9\ g[/tex]
So , [tex]n=\dfrac{111}{110.9} \approx1[/tex]
Therefore , the molecular formula is also [tex]CaCl_2[/tex] .
Hence , this is the required solution .
Strontium consists of four isotopes with masses of 84 (abundance 0.50%), 86 (abundance of
9.9%), 87 (abundance of 7.0%), and 88 (abundance of 82.6%).
Calculate the atomic mass of
strontium.
Answer:
M = 87.71 amu
Explanation:
The masses of 4 isotopes of Strontium with abundance is as follows :
84 (abundance 0.50%), 86 (abundance of 9.9%), 87 (abundance of 7.0%), and 88 (abundance of 82.6%). Let M is the atomic mass of Strontium. So,
[tex]M=0.50\%\ \text{of}\ 84+9.9\%\ \text{of}\ 86+7\%\ \text{of}\ 87+82.6\%\ \text{of}\ 88\\\\M=\dfrac{0.5}{100}\times 84+\dfrac{9.9}{100}\times 86+\dfrac{7}{100}\times 87+\dfrac{82.6}{100}\times 88\\\\M=87.71\ \text{amu}[/tex]
So, the atomic mass of Strontium is 87.71 amu.
PLZ HELP CHEMISTRY! WILL REWARD! Please correct me if I'm wrong.
I marked my answers as x.
1. During a titration, 50.0 ml of 0.2M NaOH were required to neutralize 50.0ml of H3PO4. What's the concentration of the H3PO4 solution?
A. 1.8M
B. 0.6M
C. 0.07M
x D. 0.2M
2. Attached photo - Using the two cell reduction potentials shown for their corresponding reaction, calculate the cell potential for a voltaic cell made from these two systems.
A. –1.68 V
B. –0.78 V
C. 0.78 V
D. 1.68 V
3. If atoms from two different elements react to form a compound, the element with a higher _______ will have a negative oxidation number.
A. atomic number
B. atomic radius
C. energy
x D. electronegativity
4. During the electrolysis of an aqueous solution of sodium nitrate, a gas forms at the anode, what gas is it?
x A. Oxygen
B. Hydrogen
C. Sodium
D. Water
5. The lithium-ion in a lithium-ion battery moves from one side to the other by
A. moving through the cathode.
B. moving through the anode.
x C. passing through the separator.
D. passing through the device.
6. The use of water in a heat exchanger is taking advantage of water's
x A. high specific heat.
B. significant expansion during boiling.
C. solid state when frozen.
D. polar molecular nature.
Which of the following goes through the largest volumetric change?
A. Water when it boils into steam
x B. Water when it freezes into ice
C. Water when it's heated from 1oC to 99oC
D. Ice when it melts into water
Answer:
Option [tex]C. \:\:0.07 \:M[/tex] is the right choice.
Explanation:
Write down the equation and balance it.
[tex]3NaOH+H_3PO_4\Rightarrow \:Na_3PO_4+3H_2O[/tex]
For one mole of phosphoric acid, we need three moles of sodium hydroxide.
Concentration of [tex]NaOH[/tex] [tex]=Molarity=\frac{moles}{Volume}[/tex]
Mole of [tex]NaOH[/tex] [tex]= 0.2\times 50\times 10^{-3}[/tex]
[tex]=0.01\:moles[/tex]
Moles of [tex]H_3PO_4=\frac{0.01}{3}=0.0033\:moles[/tex]
Finally:
Concentration of [tex]H_3PO_4=\frac{0.0033}{0.05}=0.067\:M[/tex]
What does it mean to be "moderated by water"?
water is watching over you
Answer:
it means the higher the water content in the air, the more moderate (less extreme) the climate is.
Sort the examples based on whether they describe a physical change or a chemical reaction. growth of a seed into a seedling tarnishing of silver wax melting from applied heat making caramel by burning sugar grinding wheat to make flour adding copper with gold to make jewelry
Answer: I did the research myself since I couldn’t find the answers.
Physical change:
Wax melting from applied heat
Grinding wheat to make flour
Adding copper with gold to make jewelry
Chemical Reaction:
Growth of a seed into a seedling
Making caramel by burning sugar
Tarnishing of silver
Explanation:
Thanks google
Answer:
Physical change:
Wax melting from applied heat
Grinding wheat to make flour
Adding copper with gold to make jewelry
Chemical Reaction:
Growth of a seed into a seedling
Making caramel by burning sugar
Tarnishing of silver
Explanation: I had to take a test.
How many molecules are in 2g of O2?
Answer:
That means that the number of O2 molecules present in 2g of O2 is equal to 0.0625*NA. That's 3.76375*10^22. That is a lot of molecules. And we have not even reached the atomic level
The chemist plans to try to identify the unknown liquid by measuring the density and comparing to known densities. First, from her collection of Material Safety Data Sheets (MSDS), the chemist finds the following information: liquid density methyl acetate dimethyl sulfoxide glycerol acetone ethanolamine Next, the chemist measures the volume of the unknown liquid as 1698 and the mass of the unknown liquid as . Calculate the density of the liquid. Round your answer to significant digits. Given the data above, is it possible to identify the liquid? yes no If it is possible to identify the liquid, do so.
Answer:
a) Density of unknown liquid = 0.934 g/cm³
b) Yes
c) The unknown liquid is methyl acetate
Note: The question is missing some parts; the densities of the liquids from the material data sheet. A similar question is given below:
A chemist working as a safety inspector finds an unmarked bottle in a lab cabinet. A note on the door of the cabinet says the cabinet is used to store bottles of acetone, chloroform, methyl acetate, glycerol, and ethanolamine.
The chemist plans to try to identify the unknown liquid by measuring the density and comparing to known densities. First, from his collection of Material Safety Data Sheets (MSDS), the chemist finds the following information: (the attachment below shows a table of the Material Safety Data Sheet)
Explanation:
Part 1
Density = mass/volume
Mass of unknown liquid = 512.0 g
Volume of unknown liquid = 0.548 L = 548 cm³ (Note: 1 L = 1000 cm³)
Density = 512.0 g/548 cm³ = 0.934 gcm³l to 3 significant figures.
Part 2
Yes, it is possible to identify the liquid from the value of its calculated density when compared with that of the known liquids in the Materials and Safety Data Sheet.
Part 3
The unknown liquid is methyl acetate since the density of the unknown liquid matches its density.
what is the scientific name for the chemical formula know as P2Os
Explanation:
I know only P2O5 = Phosphorus pentoxide
Marcos and Helen study the electron configurations of neutral atoms. They draw the
atomic models shown. Due to their electron structure, what do the two atoms have in
common?
a. period
b. No answer text provided.
c. group
d. mass number
e. atomic number
To see the number of atoms of an element in a given molecule we need to multiply stoichiometry to the number that is written on the foot of the element that is stoichiometry. The correct option is option C.
What is atom?Atom is the smallest particle of any element, molecule or compound. Atom can not be further divided. Atoms contains nucleus in its center and electron that revolve around the atom in fixed orbit.
In the nucleus, proton and neutron are present. Electron has -1 charge while proton has +1 charge. Neutron is neutral that is it has no charge. So overall the charge of nucleus is due to only proton, not by neutron.
In the two figure the number of electrons in the outermost shell or valence shell is 2. The group of periodic table that has valency 2, is the alkaline earth metals. So, the group number, the two atoms have in common.
Therefore, the correct option is option C.
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Atom A has five protons, four neutrons, and five electrons. Atom
B has five protons, six neutrons, and five electrons.
Are atoms A and B isotopes of the same element? Explain how
you know.
SELECT AN ANSWER
They are of the same element because
they have a different number of neutrons.
They are of the same element because
they have the same number of protons and
electrons, but a different number of
neutrons.
They are of the same element because
they have the same number of protons and
neutrons, but a different number of
electrons.
They are of the same element because
they have the same number of protons.
SUBMIT
Answer:
they are the same element because they have the same number of protons and electrons,but a different number of neutrons
Part 1: Cats falling out of windows
Answer:
A cat that falls out of the window even if it seems to be doing well, must urgently go to a veterinary clinic in order to be placed under surveillance for at least 24 to 72 hours
Explanation:
Convert 9541mg to kg
Answer: 9.541 kg
Explanation:
Answer:
i believe it is 0.009541
What problem occurs if the firework mixture is not pure (i.e., they are dirty or contaminated)?
Answer:
Fireworks cause broad air contamination in a short measure of time
Explanation:
Fireworks cause broad air contamination in a short measure of time, leaving metal particles, hazardous poisons, destructive synthetic compounds and smoke noticeable all around for quite a long time. A portion of the poisons never completely decay or break down, but instead stick around in the earth, harming all they come into contact with
If the firework mixture is not pure, it is capable of causing risks to health conditions by creating hazardous explosives.
Fireworks originate from the Greek word ''pyrotechnics" which implies fire art. Fireworks is simply a missile that explodes with booms and bursts of vibrantly colorful light in a very controlled fashion.
The chemical components used in the preparation of fireworks are dependent upon the color they produce. These include:
Oxidizing agents such as; barium nitrate (green color), strontium nitrate (red color), etc.fuels such as metal powders, charcoal, etc.If these mixtures are impure, it is certain that these can pose a greater risk related to health conditions by exploding abruptly. These impure gases get mixed with the air and also result in environmental hazards by mixing with the water in lakes, rivers, and streams.
In conclusion, the impurity of firework mixture has a greater effect on human health conditions.
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1. List the three measurements that are helpful when working with a gas.
Answer:
Three measurements that are helpful to know when working with a gas are volume, temperature, and pressure. container.
Hope this helps if its wrong correct me.
carboxylamine reaction
Answer:
Explanation:
The direct reaction of a carboxylic acid with an amine would be expected to be difficult because the basic amine would deprotonate the carboxylic acid to form a highly unreactive carboxylate.
How many millimeters of 5 M NaCl are required to prepare 1500 mL of 0.002 M NaCl?
Answer:
The correct answer is 0.6 mL.
Explanation:
We use the mathematical expression:
Ci x Vi = Cf x Vf
Where Ci is the initial concentration (5 M); Cf and Vf refers to final concentration (0.002 M) and final volume (1500 mL). With the given data, we calculate the initial volume (Vi):
Vi = (Cf x Vf)/Ci = (0.002 M x 1500 mL)/(5 M) = 0.6 mL
Therefore, we need 0.6 mL of 5 M NaCl to prepare the solution with the requested dilution.
The table shows the students data from an investigation about a plant growth and five plants of the same type what is the best way to display this data for analyst
Answer:
This question is incomplete
Explanation:
The question is incomplete because of the absence of the table but since the question says there are data from an investigation about a plant growth and five other plants (making six) of the same type, the best way to display this type of data for analyst is to use the grouped bar chart. The grouped bar chart will display the data obtained (from an investigation on plant growth) from different students on each of the six plants (of the the same type).
Colours are usually used to identify the bars (of a group) or could be used to separate the group from other groups but in this case, colours are better used to identify the bars of a group.
If society took the threat of global warming seriously, what kinds of changes would you expect to see in how that society works?
Answer:
Global warming occurs a result of human activities which affects the environment negatively . It usually occurs over a long period of time. The global warming causes climate changes as a result of the ozone layer depletion.
If society took the threat of global warming seriously there will be changes in how humans handle the environment and the resources. Carbon emissions would be greatly reduced. Forest resources such as trees would also be treated specially and there would have been a reduction in mass deforestation as a result of urbanization
Draw a structural formula for 4,4-dichlorocyclohexanecarboxylic acid.
Answer:
See attached picture.
Explanation:
Hello,
In this case, for the required carboxylic acid, we should consider a central cyclohexane that at the first carbon has a carboxyl group COOH and at the fourth carbon has two chlorine radicals as shown on the attached picture. This type of compounds need to have the carboxyl group outside the ring in order to be considered as acids, otherwise the octet rule may not be respected for a cyclic carbon.
Regards.
If a metal has a density of 8.9 g/ml, and a volume of 200mls, what is the mass?
Answer:
The answer is 1780 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
volume of metal = 200 mL
density = 8.9 g/mL
We have
mass = 8.9 × 200
We have the final answer as
1780 gHope this helps you
For the following electron-transfer reaction:
2Ag^+(aq) + Mn(s) rightarrow 2Ag(s) + Mn^2+(aq)
1. The oxidation half-reaction is:_______
2. The reduction half-reaction is:_______
Answer:
1. The oxidation half-reaction is: Mn(s) ⇄ Mn²⁺(aq) + 2e⁻
2. The reduction half-reaction is: Ag⁺(aq) + 1e⁻ ⇄ Ag(s)
Explanation:
Main reaction: 2Ag⁺(aq) + Mn(s) ⇄ 2Ag(s) + Mn²⁺(aq)
In the oxidation half reaction, the oxidation number increases:
Mn changes from 0, in the ground state to Mn²⁺.
The reduction half reaction occurs where the element decrease the oxidation number, because it is gaining electrons.
Silver changes from Ag⁺ to Ag.
1. The oxidation half-reaction is: Mn(s) ⇄ Mn²⁺(aq) + 2e⁻
2. The reduction half-reaction is: Ag⁺(aq) + 1e⁻ ⇄ Ag(s)
To balance the hole reaction, we need to multiply by 2, the second half reaction:
Mn(s) ⇄ Mn²⁺(aq) + 2e⁻
(Ag⁺(aq) + 1e⁻ ⇄ Ag(s)) . 2
2Ag⁺(aq) + 2e⁻ ⇄ 2Ag(s)
Now we sum, and we can cancel the electrons:
2Ag⁺(aq) + Mn(s) + 2e⁻ ⇄ 2Ag(s) + Mn²⁺(aq) + 2e⁻
there is an ice cream shop 6 blocks north of your hotel. how many minutes will it take to walk there and back
Answer:
48 minutes i think
Explanation:
On average, how many hours of sleep do teenagers need each night? 7 hours 7.5 hours 8 hours 8.5 hours
Answer:
8.5
Explanation:
Took the test and got it correct
On an average, teenagers require 8.5 hours of sleep each night to maintain good health.
Who are teenagers?
A teenager, or teen, is someone who is between 13 and 19 years of age. They are called teenagers because the number of their age contains the suffix "teen". The word "teenager" is often associated with adolescence. Most neurologists consider the brain still developing into a person's early or mid-20s. A person becomes a teenager when they become 13 years old. It ends when they turn 20 years old. Teenagers who are between 13 and 17 years old are considered both children and teenagers in most countries. Teenagers who are 18 and 19 years old may be regarded as both teenagers and adults.
The way the word is used varies. Most societies have rites of passage to mark the change from childhood to adulthood. These ceremonies may be quite elaborate.During puberty, rapid mental and physical development occurs. Adolescence is the name for this transition period from childhood to adulthood.
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