Answer:
NA = 6.02214076×10^23 mol−1.
Explanation:
1 mole of helium gas contains 6.02 x10^23 helium atoms. So multiply this by 3 after solving the equation.
There are 1.8066 x 10 ^24 atoms in 3 moles of helium
1 mole of any substance is equal to 6.022 × 1023 atoms , This is called the Avogadro's Number and it represents 12 grams of pure carbon.
Hence,
I mole of Helium = 6.022 × 1023 atoms
Therefore,
3 moles of helium will be 3 x 6.022 × 1023 atoms
3 moles of helium =1.8066 x 10 ^24 atoms
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A method that uses a mathematical equation and the half-life of decay to determine the exact date of a fossil is known as _______. A. Relative dating c. Absolute dating b. Comparative dating d. Half-life dating Please select the best answer from the choices provided A B C D
Answer:
c. Absolute dating
Explanation:
Absolute dating is a mathematical process that is still used today by traditional archaeology to determine the chronological age of a given discovery. This type of dating provides an era or time interval expressed in numbers. This system would therefore be in contrast with relative dating, which positions the events concerning a known reference but without ascertaining the annual difference between the elements taken into consideration.
When we talk about absolute dating we are talking about four different systems:
Radiometric dating, which in turn is divided between carbon-14 and potassium-argon.The luminescence, divided into “Thermoluminescence” e “OSL”.Dendrochronology and;Dating with amino acids.Answer:
c
Explanation:
what is the concentration of a solution if it has 25g of salt dissolved in 400 ml of water?
Answer:
Solubility ≡ 62.5 ⋅ g ⋅ 100 ⋅ m L − 1
Explanation: We want Concentration = Mass of solute 100 mL volume of solvent .
We make the reasonable assumption that the volume of solution is equal to 40 ⋅ m L
Explanation:
Answer:
62,5 g/l
Explanation:
Concentration = m(NaCl) / V(H2O)
Firstly, we change ml to l, so 400 ml becomes 0,4 l.
Divide 25 by 0,4 and you get 62,5 g/l.
what are the two basic parts of the atom
Answer:
The nucleus and electrons the electrons orbit around the nucleus.
Explanation:
Answer:
nucleus and electrons
Explanation:
nucleus in the middle of the atom containing protons and nuetrons and the outer region contains the electrons
Fill in the blank: An object is most likely to sink in water if
Answer:
An object floats when the weight force on the object is balanced by the upward push of the water on the object. ... If the weight force down is larger than the upward push of the water on the object then the object will sink. If the reverse is true then the object will rise – rising is the opposite of sinking.
Explanation:
Take what you will from this.
Answer:
Wood, rubber, plastic, egg, palm leaves, styrofoam, and some types of natural rocks too!
Chemistry:
A sample of helium occupies 1820 mL at 719 mmHg. Assume that the temperature is held constant and determine (a) the volume of the helium at 752 mmHg and (b) the pressure, in mmHg, if the volume is changed to 345 mL
Answer:
You can use the Boyles Law formula
P1V1 = P2V2
Substitute what you have and solve for the new volume. There is no need to do any conversions:
730mmHg * V1 = 719mmHg* 1820mL
V1 = 719mmHg* 1820mL / 730mmHg
V1 = 1792mmHg
The correct answer should have only 2 significant figures: Volume = 1800mL
Explanation:
hope that this helps
The volume of the helium at 752 mmHg is 1740 ml and the pressure, in mmHg, if the volume is changed to 345 mL is 3792 mmHg.
What is pressure?Pressure is defined as the force applied perpendicular to an object's surface per unit area over which that force is dispersed.
It is also defined as the physical force exerted on an object.
(a) The volume of the helium at 752 mmHg
P1V1 = P2V2
719 mmHg x 1820 ml = 752 mmHg x V2
V2 = 719 mmHg x 1820 ml / 752 mmHg
V2 = 1740 ml
(b) The pressure, in mmHg, if the volume is changed to 345 mL
719 mmHg x 1820 ml = P2 x 345 ml
P2 = 719 mmHg x 1820 ml / 345 ml
P2 = 3792 mmHg
Thus, the volume of the helium at 752 mmHg is 1740 ml and the pressure, in mmHg, if the volume is changed to 345 mL is 3792 mmHg.
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A gas is at 45L at 227K. What volume would the gas be at 311K?
Answer:
sorry I don't know the ans.. I'm truly sorry
What is the number 98.907 called? *
1 point
43
Тc
Technetium
98.907
atomic number
atomic mass
element symbol
element name
Give one reason why metal spoons are electroplated with silver
Answer:
To give non expensive spoons the appearance and the chemical resistance of the expensive ones.
Explanation:
Companies are cheap and under strict guidelines. This is their loophole.
Electroplating is the coating of metals by the process of hydrolysis. Metallic spoons are electroplated with silver to give an expensive appearance and chemical resistance.
What is electroplating?Electroplating has been known as the electrochemical deposition of the metal on another solid metallic substrate by the process of hydrolysis or cation reduction through electric current.
This process is used to coat metals to prevent them from getting corroded. Also, it has been used to give a decorative and expensive look to ordinary metal.
The metallic spoons are electroplated with silver metal to make them look expensive and rich. The silver moves from the anode towards the cathode where the spoon is in the presence of the current.
Therefore, the metals are electroplated by silver for an expensive and rich look.
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What do you think the study of chemistry might be about?
Answer:
Think about it. Chemistry is the study of matter.
Explanation:
Anything that has mass and takes up space, and the changes that matter will have when it is in different environments or conditions. Chemistry is used everyday with the development of plastics, wood burning, prescriptions, cosmetics, etc. Everything you touch is made of an element. there's 5 branches of chemistry including Biochemistry, organic chemistry and physical chemistry. -(you find the others).
Chemistry studies our surroundings on a molecular level through atoms and molecules with chemical reactions and understanding the specific properties. There are patterns on the periodic table you should check out.
good luck and have fun!
Answer:
chemistry is the study of structure of substance and what happens to them in different conditions
An air bubble in a bar of ivory soap at room temperature (23 °C) has a
volume of 0.80 mL. What volume does the air bubble have when it is
heated in a microwave to 88 °C? *
Answer:
V2 = 0.98mL
Explanation:
Using Charles' law equation which I as follows:
V1/T1 = V2/T2
Where;
V1 = initial volume (mL)
T1 = initial temperature (K)
V2 = final volume (mL)
T2 = final temperature (K)
Based on the information provided in this question; V1 = 0.80 mL, V2 = ?, T1 = 23°C, T2 = 88°C
Temperature in °C must be converted to Kelvin
T1 (K) = 23°C + 273 = 296K
T2 (K) = 88°C + 273 = 361K
Hence, using V1/T1 = V2/T2
0.80/296 = V2/361
296 × V2 = 0.80 × 361
296V2 = 288.8
V2 = 288.8/296
V2 = 0.9756
V2 = 0.98mL
What cell has a membrane and ribosomes
describe a system that explains or demonstrates how action/reaction pairs must naturally exchange energy as forces act within the system. Please try and use Claims Evidence Reasoning.
Answer:
Wait so is there a amount of sentences that you have to write
A bottle of water has a volume of 560ml and a mass of 1250g. What is the density
Answer:
this is so u can give him brainliest, he deserves it
Explanation:
2.22 is correct
B3F10 what compound name is this?
Answer:
Naming Compounds
Naming Ionic Compounds
An ionic compound is named first by its cation and then by its anion.
LEARNING OBJECTIVES
Convert between the chemical formula of an ionic compound and its name
KEY TAKEAWAYS
Key Points
Most cations and anions can combine to form neutral compounds (typically solids under normal conditions) that are usually referred to as salts.
The net charge of an ionic compound must be zero. Therefore, the number of cations and anions in an ionic compound must be balanced to make an electrically neutral molecule.
When naming ionic compounds, the cation retains the same name as the element. The anion’s name is similar to the elemental name, but the ending of the name has been removed and replaced with “-ide.”
If a metallic element has cations of different charges, which cation is used has to be indicated by its suffix (an older method) or by Roman numerals in parentheses after its name in writing (the Stock system ).
Key Terms
Stock system: A system of naming that includes using Roman numerals to indicate the charge on transition metals.
In chemistry, an ionic compound is a chemical compound in which ions are held together by ionic bonds. Usually, the positively charged portion consists of metal cations and the negatively charged portion is an anion or polyatomic ion. Ionic compounds have high melting and boiling points, and they tend to be hard and brittle.
Ions can be single atoms, as the sodium and chlorine in common table salt (sodium chloride), or more complex (polyatomic) groups such as the carbonate in calcium carbonate. But to be considered an ion, they must carry a positive or negative charge. Thus, in an ionic bond, one ‘bonder’ must have a positive charge and the other a negative one. By sticking to each other, they resolve, or partially resolve, their separate charge imbalances. Positive to positive and negative to negative ionic bonds do not occur.
Most cations and anions can combine to form solid compounds that are usually known as salts. The one overriding requirement is that the resulting compound must be electrically neutral: therefore the ions Ca2+ and Br– combine only in a 1:2 ratio to form calcium bromide, CaBr2. Because no other simpler formula is possible, there is no need to name it “calcium dibromide.” CaBr2 can be named using either the Stock method or the older, classic way of naming.
For example, CuCl2 indicates a molecule where one Cu2+ cation associates with two Cl– anions to form a neutral compound. Its systematic name is copper (II) chloride, where copper’s oxidation number is indicated in parentheses. Its older name is cupric chloride.
The Stock Method of Naming
An ionic compound is named first by its cation and then by its anion. The cation has the same name as its element. For example, K+1 is called the potassium ion, just as K is called the potassium atom. The anion is named by taking the elemental name, removing the ending, and adding “-ide.” For example, F-1 is called fluoride, for the elemental name, fluorine. The “-ine” was removed and replaced with “-ide.” To name a compound, the cation name and the anion named are added together. For example, NaF is also known as sodium fluoride.
If either the cation or the anion was a polyatomic ion, the polyatomic ion name is used in the name of the overall compound. The polyatomic ion name stays the same. For example, Ca(NO3)2 is called calcium nitrate.
For cations that take on multiple charges (typically transition metals), the charge is written using Roman numerals in parentheses immediately following the element name. For example, Cu(NO3)2 is copper (II) nitrate, because the charge of two nitrate ions (NO3−1) is 2(-1) = -2. Since the net charge of the ionic compound must be zero, the Cu ion has a 2+ charge. This compound is therefore, copper (II) nitrate. The Roman numerals in fact show the oxidation number, but in simple ionic compounds this will always be the same as the metal’s ionic charge.
The Old, Classic, or Common Way of Naming
image
Names of some ionic compounds: Common, or trivial, names of compounds are sometimes used in informal conversations between chemists, especially older chemists. Systematic names are formal names that are always used in print.
Since some metallic elements form cations that have different positive charges, the names of ionic compounds derived from these elements must contain some indication of the cation charge. The older method uses the suffixes -ous and -ic to denote the lower and higher charges, respectively. In the cases of iron and copper, the Latin names of the elements are used (ferrous/ferric, cuprous/cupric). This system is still used, although it has been officially supplanted by the more precise, if slightly cumbersome, Stock system. In both systems, the name of the anion ends in -ide.
Explanation:
An initially deflated and flat balloon is connected by a valve to a storage tank containing helium gas at 1 MPa at ambient temperature of 20 degrees C. The valve is open and the balloon is inflated at constant pressure of 100 kPa (atmospheric pressure) until it becomes spherical at D1 = 1m. If the balloon is larger than this, the balloon material is stretched giving a pressure inside as:
P = Po + C(1-(D1/D))(D1/D)
The balloon is slowly inflated to a final diameter of 4m, at which point the pressure inside is 400 kPa. The temperature remains constant at 20 degrees C. Determine the work done during the overall process.
Answer:
14660.75 kJ.
Explanation:
We are given from the question above that the pressure inside is represented by this equation:
P = Po + C(1-(D1/D))(D1/D).
Thus, P = 100 + C (1 - 1/4) (1/4). Therefore, P which is = 400 is;
400 = 100 + C (1 - 1/4) (1/4).
Hence, C = 1600. And the equation can be written as P = 100 + 1600 (1 - (D1/D))(D1/D).
The work done during the entire process, w = (work done during the process 1 to 2) + (work done duringbthe process 2 to 3 ).
Therefore, work done during the process 1 to 2 = P(V2 + V1) = 100( π/6 - 0).
{NB: V2 is gotten from π/6 × D^3. Where D^3 = 1. }
Hence, work done during the process 1 to 2 = 52.36 kJ.
So, the work done duringbthe process 2 to 3 ) is going to be the integration of PdV. Where P = 100 + 1600 (1 - (D1/D))(D1/D) and dV = π/2 D^2 dD. Taking the upper and the lower limit as 4 and 1 respectively.
After the integration (kindly check attached picture for the process) the work done duringbthe process 2 to 3 = 14.61 × 10^3 kJ.
Therefore, The work done during the entire process, w = (work done during the process 1 to 2) + (work done duringbthe process 2 to 3 ).
The work done during the entire process, w = 52.36 kJ + 14.61 × 10^3 kJ. = 14660.75 kJ.
Find the three missing terms pound in this puzzle.
e t d w a t
s p l t I h
n u o e r I
e h c y m n
d n a p x e
Can someone help me please, I think it may be B but i'm not sure..
Answer:
The Answer is D
Explanation:
In an electrically neutral atom,
the number of protons equals the number of neutrons.
the number of protons equals the number of electrons.
the number of neutrons equals the number of electrons.
Answer:
B
Explanation:
I may be wrong sorry...
The Protons and Neutrons are in the Nucleus of the Atom, the Atomic Clouds contain the Electrons.
What does the identity of an element depend on the number of?
A. protons in the atom
B. electrons in the atom
C. protons and neutrons in the nucleus
D. neutrons in the atom
Answer: A. protons in the atom
Explanation: I just took the test and got a 100% so this should be right. Unless the question is worded differently than mine then it should be right. Hope this helps :)
Answer:
A
Explanation:
Identify the preposition in the following sentence.
Khari will finish typing his science report before dinner.
O his
o
O finish
O before
PLEASE HELP!!!
need help asap!!
Answer:
the tree branch is puching up on his foot
what does it mean when we say chemistry is the structures , composition, transformation and property of chemicals????pleazzz i wanna the right answer?
Explanation:
Chemistry is the scientific discipline involved with elements and compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances.
How many moles are in 3.75 × 10^23 F atoms?
Answer in units of mol.
Answer:
The answer is 0.62 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\ [/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{3.75 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{3.75}{6.02} \\ = 0.6229235...[/tex]
We have the final answer as
0.62 molesHope this helps you
What properties of an element are affected by electron distribution?=
Define malleability.
Define ductility.
State one reason gold is used in jewelry.
Why is mercury no longer used in many devices?
What are the properties of nonmetals?
List the states of matter in which nonmetals can exist and give one example of each state.
What are the physical properties and uses of sulfur?
What are the physical properties and uses of bromine?
What are the physical properties and uses of helium?
Define “metalloid.”
Why would it be difficult to decide whether or not an element was a metalloid based on its properties?
Why is silicon used extensively in electronics?
What are borosilicates used for?
Why is the use of arsenic as an insecticide decreasing?
What is a main application of antimony?
Answer:
Capable of being hammered out thin
Explanation:
, as certain metals; malleable. capable of being drawn out into wire or threads, as gold. able to undergo change of form without breaking.
Which of the following statements is true about the current in a wire?
A. Depends only on the resistance of the wire
B. Depends only on the potential difference applied
C. Depends on both resistance and potential difference
D. Does not depend on resistance and potential difference
Answer:
the answer is a
Explanation:
Voltage can be thought of as the pressure pushing charges along a conductor, while the electrical resistance of a conductor is a measure of how difficult it is to push the charges along.
What can light and other electromagnetic waves do to objects.
Answer:
It can cause a reflection
Explanation:
Reflection is when incident light (incoming light) hits an object and bounces off. Very smooth surfaces such as mirrors reflect almost all incident light
Water dissolves ionic compounds because water molecules
a. Are nonpolar.
b. Have a pH value of 14 or greater.
c. Have partially charged ends.
d. Do not contain atoms.
Water is known as the universal solvent because it can dissolve almost all ionic compounds due to its polarity that is having partially charged ends.
What is polarity?A polar compound is having the partially charged ends, where the shared pair of electrons are attracted towards the more electronegative atom, and thus have partial charges on both atoms.
In water, the shared pair of electrons are pulled towards the electronegative oxygen atom and thus O acquires a negative charge and H gets a positive charge. These charged ends are active to attack other reagents and forms hydrogen bonds with other electronegative atoms of ionic bond.
In this way water bonds to the ionic compounds and gets them easily dissolved. Hence, option C i.e., have partially charged end is correct.
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In a constant‑pressure calorimeter, 70.0 mL70.0 mL of 0.320 M Ba(OH)20.320 M Ba(OH)2 was added to 70.0 mL70.0 mL of 0.640 M HCl.0.640 M HCl. The reaction caused the temperature of the solution to rise from 23.00 ∘C23.00 ∘C to 27.36 ∘C.27.36 ∘C. If the solution has the same density and specific heat as water ( 1.00 g/mL1.00 g/mL and 4.184J/g⋅K,)4.184J/g⋅K,) respectively), what is ΔHΔH for this reaction (per mole H2OH2O produced)
Answer:
57.0kJ/mol is ΔH of the reaction
Explanation:
The reaction is:
1/2 Ba(OH)₂ + HCl → 1/2 BaCl₂ + H₂O + ΔH.
Where ΔH is the heat of reaction per mole of water.
Moles of water produced are equal to moles of HCl that are:
70.0mL = 0.070L * (0.640mol / L) = 0.0448moles HCl = Moles of water produced.
Now, heat produced is determined using coffee-cup calorimeter equation:
Q = m×ΔT×C
Where Q is heat released
m is mass of solution (70mL + 70mL = 140mL = 140g -Density of 1g/mL-)
ΔT is change in temperature (27.36°C - 23.00°C = 4.36°C)
And C is specific heat of the solution (4.184J/gK)
Replacing:
Q = 140g×4.36°C×4.184J/gK
Q = 2553.9J
This is the heat released when 0.0448 moles of water are produced, that means ΔH is:
2553.9J / 0.0448moles
ΔH = 57000J/mol =
57.0kJ/mol is ΔH of the reaction
The chemical equation shown below represents a reaction that produces fuel for certain cars. CO + H2O - CO, + H2 Which substance represented in this equation is classified as an element? F CO GH, нсо, J H2 F b G OOOO C. H 1
Answer:
The equation to this question is unclear. The equation is as follows:
CO + H2O ---> CO2 + H2
The substance classified as an element is H2.
Explanation:
An element is a substance composed of atoms of the same type. It is the simplest chemical substances that cannot be broken down by any chemical reaction. According to this question showing a chemical equation that produces fuel for certain cars:
CO + H2O ---> CO2 + H2
H2 is the substance that represents an element because it is made up of two atoms of hydrogen to form a molecule. Other substances in the reaction like (CO, CO2, H2O) are made up of two or more different atoms, hence, they are compounds not elements.
The substance represented in the given chemical equation which is classified as an element is: J. [tex]H_2[/tex]
An element can be defined as a pure substance which comprises atoms with the same atomic number (number of protons) in its atomic nuclei.
Basically, an element is any pure substance that can't be broken down, decomposed or transformed into simpler substances by chemical or physical means.
In Chemistry, some examples of an element include the following:
Carbon.Argon.Sodium.Oxygen.Hydrogen.[tex]CO + H2O --> CO_2 + H_2[/tex]
From the above chemical equation, the substance which is classified as an element is hydrogen ([tex]H_2[/tex]).
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Similar plant and animal fossils
have been found on continents
that are now separated by an
ocean. Why is this significant?