“Atomic mass” is relative to the isotope carbon-12 weighing exactly 12 atomic mass units. Therefore “atomic mass” is precisely the same as “relative atomic mass.”
Two further points:
First, atomic mass as stated on the periodic table is a average of the masses of an element’s naturally-occurring isotopes, weighted by their abundance. This is because atomic mass as normally used is a bulk property: we weigh out many trillions of atoms at a time, because we usually deal in macroscopic quantities. And that means that an average mass is more useful to us.
Second, all masses are relative masses (until the new, physical-constant-based kilogram comes online; and arguably even then). We mass something by comparing it to some standard of reference: until later this year, that something is a chunk of alloy in Paris, France. When the new standard comes into use, we will be comparing the kilogram’s gravitational mass to the strength of the electromagnetic force.
But that’s kind of trivial; it just stems from the fact that any and every measurement is a comparison to something else.
Edit: IUPAC, the world’s premier organization for the imposition of picky definitions that most people never need to use, has the following:
Atomic mass is the mass of a single atom; the unit is the Dalton or unified atomic mass unit. (I would use “isotopic mass” to specify the mass of a particular atom, but that’s not sanctioned by IUPAC.)
Relative atomic mass is the measured average mass of all atoms of a particular element in a particular sample. To make it unitless, it’s divided by the value of the unified atomic mass unit.
Standard atomic weight is the value you read off of the periodic table; it’s an Earth-based average over many samples, of experimental values of the relative atomic mass. Values are promulgated by the IUPAC Commission on Atomic Weights and Isotopic Abundances, and are revised every two years.
Most chemists refer to standard atomic weight as “atomic mass” or “atomic weight” and get on with their lives.
The unified atomic mass unit is 1/12 of the mass of an atom of carbon-12. It is sometimes called the Dalton.
Definitions taken from the IUPAC Gold Book.
As far as I can tell, relative atomic masses and standard atomic weights are made unitless so that they can be used with any convenient macroscopic mass unit to determine correct proportions for a desired chemical reaction.
Is this true Bc I’m not sure
Answer:
????? questions there no question
Answer:
what
Explanation:
Melting chocolate (a change of state) is an example of a
When water is solid, do molecules move?
Answer:
Ice is water in its solid form. Ice keeps its shape, even if it's removed from the container. The molecules in ice are locked into place and cannot move or slide past one another, but they do vibrate a little bit.
Explanation:
As the temperature drops or decreases, the water molecules gradually slow down. Eventually they stop moving and simply vibrate back and forth. At this point ice is formed, the solid phase of water. If the temperature is allowed to increase, the molecules will once again begin to vibrate faster and faster.
Answer:Ice is water in its solid form. Ice keeps its shape, even if it's removed from the container. The molecules in ice are locked into place and cannot move or slide past one another, but they do vibrate a little bit.
Explanation:
how many atoms are there in a 1 mol sample of water
Answer:
Explanation:
1 molecule has 2 hydrogens and 1 oxygen. That's 3 atoms.
1 mol of anything is 6.02 * 10^23 items. There are 3 atoms in 1 molecule
There are 6.02*10^23 * 3 atoms in a mol of water
Answer: 1.804 * 10^24 atoms in a mol of water.
In order for photosynthesis to take place, energy in the form of ______ is required.
A. Sound
B. Light
C. Electricity
D. Kinetic
In the reaction 2Li(s) + 2H2O(I) -> 2LiOH(aq) + H2(g), which compound is in the aqueous state?
A. Li
B. H2O
C. LiOH
B. H2
The substance that is in aqueous state in the reaction is LiOH from the equation shown.
What is an aqueous state?An aqueous state is a state in which a substance is dissolved in water. This implies that the substance is in solution.
Thus, the substance that is in aqueous state in the reaction is LiOH from the equation shown.
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Answer:
C
Explanation:
What describes using organisms that were only alive during a specific time period to estimate the unknown age of items
A radioactive dating
B law of superposition
C relative dating
D index fossil
Answer:
c i just took the test
Explanation:
Out of magnesium, iron, calcium, mercury, copper, or aluminum which metal would be the most useful when transporting acids or water solutions? PLEASE HELP!!! Thank you
A 2.0 sample of N2 occupy 50.0L at 15 degrees Celsius and 640mmHg. What volume will the gas occupy at 45 degrees Celsius and 160mmHg?
Answer:
220.8L
Explanation:
Given parameters:
Initial volume = 50L
Initial temperature = 15°C = 288K
Initial pressure = 640mmHg
Final temperature = 45°C = 318K
Final pressure = 160mmHg
Unknown:
Final volume = ?
Solution:
Using the combined law;
[tex]\frac{p_{1}v_{1} }{T_{1} }[/tex] = [tex]\frac{p_{2}v_{2} }{T_{2} }[/tex]
p,v and T are pressure, volume and Temperature
[tex]\frac{640 x 50}{288}[/tex] = [tex]\frac{160 x v_{2} }{318}[/tex]
160 x 288 x v₂ = 640 x 50 x 318
v₂ = 220.8L
What factors do you think should be considered in selecting a metal to use to reclaim copper? Which factor do you think is the most important? Explain.
Answer:
Aluminum
Explanation:
Aluminum would be the best choice to reuse copper from the copper chloride solution because it In the aluminum–copper reaction, the chloride ions help remove the aluminum oxide coating so that a reaction can take place through the oxidation of aluminum and the reduction of copper ions.The aluminum–copper chloride reaction is a simplified version of a waste reclamation and reduction strategy for handling toxic-waste materials.Compare the elements: Sn, Sb, Te, and I:
Which has the lowest ionization energy?
Why?
Answer:
Sn
Explanation:
Tin, Sn, will have the lowest ionization energy from the given choices.
Sn is an element is the fourth group on the periodic table.
Ionization energy is a measure of the readiness of an atom to lose an electron. The lower the value, the easier it is for an atom to want to lose an electron and vice versa.
Across a period, I.E increases progressively from left to right due to the decreasing atomic radii caused by the increasing nuclear charge which is not compensated for by successive electronic shells.
Sn, Sb, Te and I are all in the 5th period.
Over 30 species of dinosaur fossils with feathers have been discovered. Therefore, birds evolved from dinosaurs.
A.) Claim
B.) Evidence
C.) Reasoning
Calculate the mass in grams of carbon dioxide produced from 11.2 g of octane (C8H18) in the reaction above.
18 + 25 O2 --> 16 CO2 + 18 H2O
89.6 g
17.3 g
34.5 g
46.2 g
Answer:
34.6g
Explanation:
Given parameters:
Mass of Octane = 11.2g
Reaction expression;
2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O
Mass of octane = 11.2g
Unknown:
Mass of carbon dioxide produced = ?
Solution:
From the balanced reaction equation;
2 mole of octane produced 16 moles of carbon dioxide
From the given specie, let us find the number of moles;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of C₈H₁₈ = 8(12) + 18(1) = 114g/mole
Number of moles of octane = [tex]\frac{11.2}{114}[/tex] = 0.098mole
2 mole of octane produced 16 moles of carbon dioxide
0.098 mole of octane will produce [tex]\frac{0.098 x 16}{2}[/tex] = 0.79mole of CO₂
Mass of CO₂ = number of moles x molar mass
Molar mass of CO₂ = 12 + 2(16) = 44g/mol
Mass of CO₂ = 0.79 x 44 = 34.6g
Will give 50 points, If a decrease in temperature accompanies a reaction, what occurred?
Energy was released.
Energy was destroyed.
Energy was created.
Energy was absorbed.
Answer:
A.
Explanation:
Make the following conversion.
60 dkm = _____ km
6,000
0.060
60,000
0.60
Answer:
0.6
Explanation:
The melting point of table salt is 801.Is this a physical or chemical property
Answer:
Physical
Explanation:
When something melts it is still the same substance.
For example:
Ice and water are still both water, so that would be a physical change.
If a reaction changes the substance into a new/different substance then it is a chemical change.
If you have 1.26 x 1024 molecules, how many moles do you have?
Answer:
2.09 moles
Explanation:
1 mole=6.022*10^23 moles --> 1.26×10^(24)/(6.022*10^23)=2.09 moles
1.How far can you travel if you drive 4 hours and can average 120 Km/hr?
a.30 Km
b.480 Km
c.80 Km
Answer:
B
Explanation:
D=S×T
=120km/h×4hrs
=480km
Answer:
the answer is b
Explanation:
this is the answer :)
Using your knowledge of symbols, determine which compound listed must contain both copper and oxygen.
1. malachite, Cu 2CO 3(OH) 2
2. calcite, CaCO 3
3. glucose, C 6H 12O 6
4. chalcopyrite, CuFeS 2
Answer:
The correct option is Malachite which has both copper nd oxygen.
Explanation:
As we the symbol of copper is Cu while the symbols of oxygen is O. As the chemical formula of malachite is Cu₂CO₃(OH)₂. So it has Cu as well as O.
Glucose has only oxygen but no copper
Chalcopyrite has copper but no oxygen
Calcite has oxygen but no copper.
So correct answer is only malachite.
pls give brainlist
HELP ME PLEASE!!
Density (D) is defined by mass/volume .
Which item increases as heat is applied?
D
m
V
Answer:
volume
Explanation:
things expand when heat is applied taking up more space hence volume
Metal oxides are in which state?
Answer:
Metal oxides are crystalline solids that contain a metal cation and an oxide anion. They typically react with water to form bases or with acids to form salts.
Explanation:
Hope this helps!
A cylinder at left with balls evenly spaced throughout the cylinder with an arrow leading to a cylinder at right with balls stacked near the bottom of the cylinder.
Which change of state is shown in the model?
condensation
deposition
boiling
freezing
Answer:
condensation
Explanation:
The state of change shown in the diagram is a condensation process. During condensation, heat is removed from vapor or gases and then they aggregate back to the liquid state.
The image to the left is that of a typical gas molecule. To the right we have a liquid where the particles have aggregated In going from a gas to liquid, the phase change is a condensation reaction. This is a form of physical change.Answer:
Use these images to identify each state of matter.
A cylinder at left labeled A contains balls widely separated in space. A cylinder in the center labeled B contains balls stacked near the bottom of the cylinder. A cylinder at right labeled C contains balls in a layer along the bottom of the cylinder.
Match each image with the correct state of matter.
A:
gas
B:
solid
C:
liquid
Explanation: i got it right trust me
HELP!!
H2SO4 is _____.
a base
an acid
a neutral
(The 2 is small and so is 4)
Answer:
Acid
Explanation:
acid
Answer:
An acid
Explanation:
H2OSO4 is Sulfuric Acid
Mark & Sally were in lab and they were working on a chemical reactions experiment. They mixed 2 liquids together and a white sold color appeared. What can Mark & Sally conclude as their observation?
A chemical change
B physical change
Answer:
A chemical change
Explanation:
From the observation, a chemical change has ensued.
A chemical change is one in which new kind of matter is formed. It is always accompanied by energy changes . This process is not easily reversible.
This process depicted by Mark and Sally is chemical change. This reaction is a precipitation reaction since an insoluble solid has been formed. In chemical changes the process is not reversible.What is the difference between the chemical symbols CI and Cl2?
Cl refer to chlorine atoms. They don't exist naturally in that form. Rather, Cl2 refer to chlorine molecules, and they exist as that form in nature.
What is a scientific model? How is a scientific model helpful to the brain for relaying a scientific
concept?
Answer: A scientific model is a physical and mathematical and conceptual representation of a system of ideas, events or processes.
ANd also for your second question i dont know what you mean?
Explanation:
Scientists work to recognize and comprehend patterns in our world by applying their scientific expertise to provide predictions about the patterns.
What is the main purpose of scientific model?In a range of scientific specialties, from chemistry and physics to biology and the Earth sciences, research models are employed to explain and forecast the behavior of real things or systems. The ability to depict things that are too little or enormous, explain either past or present, and forecast the future are all advantages of employing model beyond nature.
Why are scientific models important?Models can help you visualize something is difficult to see or understand. Models can help in scientific predictions, process comprehension, and concept communication. Because it frequently includes a variety of hypotheses or facts, an evolutionary theory varies from other general explanations. A science simulation may be used to verify a scientific theory or to demonstrate a scientific model.
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Please help me with this question. What are two elements that will react similarly to beryllium ?
Probably the two elements with properties most like beryllium are magnesium and aluminum.
According to the electronic configuration elements that will react similarly to beryllium are magnesium and calcium.
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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HELP AND ILL PUT U ON BRAINLIEST ! -THANKS
Answer:
2Fe₂O₃
Explanation:
If the number of atoms of each element are the same on reactant and product sides, it is a balanced equation. This is not a balanced equation because the number of atoms of each element are not the same on reactant and product sides.
To balance an equation, let's first list the atoms:
FeOThen, we count the number of atoms on both sides:
1 Fe 22 O 3We multiply the number of atoms for each element on either side by the number of molecules (aka coefficient, or "big number"):
4 Fe 26 O 3To balance the equation, we need the total number for Fe on the right side to be 4, and the total number for O on the right side to be 6. We can do that by adding a "big number", or coefficient in front, which when multiplied by the number of atoms for each element, makes a balanced equation.
2 is a good value: 2 × 2 = 4, and 2 × 3 = 6.
As such:
4Fe + 3O₂ → 2Fe₂O₃
A sample of 5.0 g of hydrogen gas reacts with 5.0 g of oxygen gas.
2H2(g) + O2(g) > 2H2O
Please answer the questions in a b c d and e, or at least in any of the ones you know. Thank you.
The percent yield of the reaction has been 74.47%.
The balanced chemical equation for the reaction has been:
[tex]\rm 2\;H_2\;+\;O_2\;\rightarrow\;2\;H_2O[/tex]
(a) The theoretical yield can be calculated as:
The theoretical yield of water has been:
1 mole of oxygen produces = 2 moles of water
0.1562 moles of oxygen produces = 0.1562 [tex]\times[/tex] 2
= 0.312 moles of water.
The mass of water has been = moles [tex]\times[/tex] molecular weight
The theoretical yield of water = 0.312 [tex]\times[/tex] 18 grams
The theoretical yield of water = 5.616 grams.
(b) The limiting reactant has been the one whose concentration has been in a lesser quantity for the complete utilization of other reactants.
According to the reaction, for the complete utilization of 2 moles of Hydrogen, 1 mole of oxygen has been used.
The moles of 5 grams Hydrogen:
Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]
Moles of hydrogen = [tex]\rm \dfrac{5}{1}[/tex]
Moles of hydrogen = 5 mol.
Moles of Oxygen = [tex]\rm \dfrac{5}{32}[/tex]
Moles of oxygen = 0.1562 mol.
For the complete utilization of 5 moles of hydrogen 2.5 moles of oxygen has been required.
Since the oxygen has been present in a lesser quantity, the oxygen has been the limiting reactant.
(c) The consumption of 0.1562 moles of Oxygen has required 0.312 mol of Hydrogen. The hydrogen has been present in a higher quantity than required.
Thus. hydrogen has been the excess reactant.
(d) The remained excess reactant has been:
Remained = Total - consumed
Remained = 5 - 0.312
Remained = 4.68 mol.
The excess reactant has been 4.68 mol extra than required.
(e) The theoretical yield of water has been:
1 mole of oxygen produces = 2 moles of water
0.1562 moles of oxygen produces = 0.1562 [tex]\times[/tex] 2
= 0.312 moles of water.
The mass of water has been = moles [tex]\times[/tex] molecular weight
The theoretical yield of water = 0.312 [tex]\times[/tex] 18 grams
The theoretical yield of water = 5.616 grams.
The actual yield of water has been 4.2 grams.
The percent yield of water = [tex]\rm \dfrac{Actual\;yield}{Theoretical\;yield}\;\times\;100[/tex]
The percent yield of water = [tex]\rm \dfrac{4.2}{5.616}\;\times\;100[/tex]
The percent yield of water = 74.74 %
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Answer:
a- 5.616
b- Oxygen
c- hydrogen
d- 4.68 extra
e- 74.47%
I hope this helps! Cheers ^^
I have similar chemical and physical properties to calcium but my molecular mass is lower, what element am I?
-Potassium
-Scandium
-Magnesium
-Strontium