Dalton was a chemist who discovered the “law of multiple proportion” in chemical reaction in early nineteenth century. For example, element of tin, he observed, interacted with oxygen to produce two different masses but in proportion 1:2. (Now, this is known to correspond to the formation of tin-monoxide and tin-dioxide, with one and two atoms of oxygen, respectively.)
From such and related studies, he proposed his theory of chemical elements: (a) that all elements are composed of ‘atoms’, the hypothetical indivisible constituents of matter of the ancient Greek thinkers, like, Democritus, and (b) that the elements differ from one another due to the atoms of different masses and sizes that constitute an element.
The modern theory of chemistry says that an element consists of an atom that consists of a heavy nucleus with positively charged ‘protons’ (and most often also the neutral particles called ‘neutrons’) at its center and, an equal number of negatively charged (and much lighter) ‘electrons’, distributed around it in discrete energy shells. Further, the elements differ from one another by the number of positively charged protons in their nucleus, the so-called atomic number, Z, of an atom. Finally, molecules are formed as well as chemical reactions take place, through the exchange or transfer of the electron(s) in the outermost shells of the reacting atoms (and/or molecules).
I need help with the 2nd part first gets brainlist
Answer:
7. 4H₂O
Elements: Hydrogen, Oxygen
Number of molecules: 4
Number of elements: 8 H, 4 O
Number of Atoms: 12
Explanation:
The elements are determined by the their symbol i.e. H = hydrogen.
The number of molecules is determined by the coefficient ( the number in front of everything, in this case 4).
The number of elements is determined by the coefficient and the subscripts. Multiply the coefficient by the subscript after each element. When there is no subscript, it is equal to 1. 4H₂ = 4x2 = 8; 4O = 4x1 = 4.
The number of atoms is all the individual elements added together. 8+4 = 12.
If the density of a substance is 2.18 g/mL, how would you find the density given that the mass is 0.987 kg and the volume is 4.52 x 102 mL?
Answer:
Explanation:
Convert mass in gms .. 987 gms
Density = mass/ volume
= 987/4.52 x102
= 2.18 g/mL
Who still uppppppp and boreddddd
Answer:
me
Explanation:
The boiling of soy oil determined by a student in the laboratory turned out to be 319.5 oC. The accepted value of this melting point is 300 oC. What is the percent error in this reading?
Answer:
Percent error = 6.5%
Explanation:
Given data:
Measured value = 319.5°C
Accepted value = 300°C
Percent error = ?
Solution:
Formula:
Percent error = measured value - actual value / actual value × 100
Now we will put the values in formula.
Percent error = 319.5°C - 300°C/300°C × 100
Percent error = 19.5 °C /300°C × 100
Percent error = 0.065× 100
Percent error = 6.5%
What happens when you add salt to very cold ice?
Which types of matter are made of atoms
a. Mixtures
b. Elements
C. Compounds
D. All of the above
Answer:
D all above yes I think it's all above
Answer: D
Explanation: All of the above.
Plz mark brainliest:)
What is the mass of 4.49 x 10º carbon dioxide, CO2, molecules?
How many atoms are in the following formula?
3Al2O3
Answer:
15 atoms total
Explanation:
2 Al atoms + 3 O atoms = 5 Al2O3 atoms
5 Al2O3 atoms * 3 = 15
another way to do it is:
2 Al atoms * 3 = 6 Al atoms
3 O atoms * 3 = 9 O atoms
6+9 =15 atoms total
The number of atoms in the given 3Al₂O₃ is 15 atoms.
What are atoms?Atoms are the smallest unit of every matter. It contains charged particles present inside the atoms. They are electrons, protons, and neutrons. Atoms are of four types, description, isotopes, radioactive, and ions.
These atoms are the ions, that are charged, and the charged ions make bonds with each other to form compounds. Aluminum oxide is a compound that is formed by combining aluminum and oxygen atoms.
The compound is 3Al₂O₃
This means there are three moles of aluminum, and three moles of oxygen.
2 Al atoms + 3 O atoms = 5 Al₂O₃ atoms
5 Al₂O₃ atoms x 3 = 15
The elaborative way is:
2 Al atoms x 3 = 6 Al atoms
3 O atoms x 3 = 9 O atoms
6 + 9 =15 atoms total
Thus, the number of atoms is 15 atoms.
To learn more about atoms, refer to the link:
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Which pair of symbols represents nuclei with the same number of neutrons?
A. 56 Co and 580
B. 57Co and 58Ni
c. 57Fe and 58 Ni
D. 57Mn and 57Fe
Answer:
B
Explanation:
Mass number = number of neutrons + number of protons
Atomic number is the number of protons in the nucleus.
58Ni : 58 is the number of neutrons + number of protons
atomic number of Ni is 28. Thus, 58 -28 = 30 neutrons
57Co ; 57 is the number of neutrons + number of protons
number of Co is 27. Thus, 57 – 27 = 30 neutrons
What did the Bohr model assume about the motion of electrons?
A. All electrons move in a circular orbit around the nucleus.
O
B. Electrons do not have a specific path around the nucleus.
OC. All electrons move in a single cloud layer around the nucleus.
D. Electrons always remain in the same location around a nucleus.
Answer:
A
Explanation:
THAT'S THE ANSWER EYEUSKSBAW
A student compared some chemical and physical properties of three pure substances. Her
data are recorded in the chart above. What is a logical conclusion the student can draw
about hare substances?
Pure substances have the same chemical and physical properties.
Pure substances have the same chemical properties, but different physical properties.
O Pure substances have the different chemical properties, but the same physical properties.
O Pure substances have different chemical and physical properties.
Answer:
letter b not c
Explanation:
next time please take a picture lucky i already took this
please hurry i’m taking a test
Answer:
im pretty sure its move at a constant rate to the right
is Mo2S6 ionic or covalent
Answer: Ionic
Explanation:
Answer:
ionic
Explanation:
where is lithium used in the body?
Answer:
Lithium is a naturally occurring alkali metal, which living organisms ingest from dietary sources and which is also present in trace amounts in the human body. In much higher concentrations, lithium is effective as a medication for mania and mood swings including manic depressive disorders
A 5 milliliter sample of water has a mass of 5 grams. What is the density of water?
Dilute hydrochloric acid reacts with sodium
2HCl(aq) + Na2CO3(aq) + 2NaCl(aq) + H2O(l) + CO2(g)
A Explain why effervescence is seen during the reaction.
Answer:
Because the reaction releases CO2 gas
Explanation:
therefore creating an effervecence within the solution as the carbonate dissociates
When many earthquakes are studied, there is another common pattern that emerges: a "Shadow Zone". This is an area, for any earthquake, on the Earth where direct S-waves don't arrive at all and P waves are refracted. What do you think causes these P waves to be refracted? *
Answer:
Sudden decrease in the velocity at the boundary.
Explanation:
The shadow zone is the zone of the earth from angular distances of 104° to 140° from a known earthquake that does not directly receive any P waves. Now, this shadow zone occurs as a result of S waves getting stopped completely by the liquid core and the P waves being refracted by the liquid core.
From earlier seismic discoveries, this boundary which is the shadow zone that does not directly receive any P-waves was found to be due to the fact that the P-waves were refracted inwards as a result of the sudden decrease in velocity at the boundary.
At what temperature does water boil at 101kPa?
Answer:
100°C
Explanation:
A liquid boils when the vapour pressure is the same as the atmospheric pressure. At 101kPa or 1 atm, water boils at the well known number of 100°C. If the pressure is different, you will have to use the Clausius Clapeyron Equation.
what is a covalent bond? Apex
Answer:
Here is the meaning of covalent bond: covalent bond: a chemical bond in which two atoms share some of their valence electrons which creates a force that holds the atoms together
Hope this helps
Sky
A chemical bond in which two atoms share some of their valence electrons creates a force that holds the atoms together.
What is a covalent bond?A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms.
Covalent bonds have high bond dissociation energy as compared to the ionic bond. The overlapping of molecular orbital is bigger in the case of the covalent bonds as compared with ionic bonds.
Hence, covalent bonds are difficult to break and stronger than ionic bonds.
Learn more about covalent bond here:
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List the steps of how a virus is able to infect your cells
Answer:
Key Points
Viral replication involves six steps: attachment, penetration, uncoating, replication, assembly, and release.
During attachment and penetration, the virus attaches itself to a host cell and injects its genetic material into it.
is muriatic acid a compound or not?
How much space does 2 x 10^22 atoms of copper take up?
Answer:
2.35mL
Explanation:
The amount of space a substance holds is its volume.
Density = mass (g) /volume (L)
Where;
mole = mass/molar mass
Since 1 mol of Cu contains 6.022 × 10^22 atoms.
There are 2 x 10^22/6.022 × 10^22 moles in 2 x 10^22 atoms of copper
2 x 10^22/6.022 × 10^22
2/6.022 × 10^(22-22)
0.332 × 10^0
0.332mol
Mole = mass/molar mass
0.332 = mass/63.5
mass = 63.5 × 0.332
mass = 21.08g
Density = mass/volume
Density of copper (Cu) is 8.96 g/cm³
8.96 = 21.08/v
V = 21.08/8.96
V = 2.35mL or cm³
Write the correct electron configurations for the following:
ments
ions
• Na (atomic # 11)
• Fe (atomic # 26)
• As (atomic # 33)
• F (atomic #9)
• Co (atomic #27)
• Ag (atomic # 47)
• K (atomic # 19)
• Cu (atomic # 29)
• Si (atomic # 14)
Answer:
Ag
Explanation:
atomic 33 because it what what sence
Which two substances are among the four major types of organic compounds made by living things?
A. Lipids
B. Carbon dioxide
C. Water
D. Nucleic acids
Answer:
I think carbon.
Explanation:
............
During the Metric Olympics yesterday, Molly's long jump was 118.3 cm. Christy accidentally recorded her results in inches. She jumped 51.18 inches. Can you help... Who won the long jump? Christy won by about 30 cm Christy won by about 30 cm Molly won by about 25 cm Molly won by about 25 cm Christy won by about 12 cm Christy won by about 12 cm Molly won by about 10 cm
Answer: Christy won Molly by 12cm
Explanation:
Ist step
Molly's ;ong jump was 118.3cm
Christy long jump was 51.18inches
2nd Step
we change christy score to cm so we can compare
1 inch = 2.54cm.
therefore 51.18 inches = 51.18 x 2.54= 129.9972cm
Christy won molly by 129.9971cm-118.3cm=11.69 rounded to 12cm
Christy won Molly by 12cm
Jack has a rock.the rock has a mass of 14g and a volume of 2cm^3.what is the density of the rock?
1
SEE ANSWER
ADD ANSWER
Answer:
7
⋅
g
⋅
c
m
−
3
Explanation:
Please help
The charge of o monatomic ion is its oxidation number.
O True
O False
O Neither
Is a backpack a good resource
for a rescue team?
What is Mercury's proximity to the sun
PLEASE HELPP
Answer:
46.943 million km
Explanation:
From an average distance of 36 million miles (58 million kilometers), Mercury is 0.4 astronomical units away from the Sun.
From an average distance of 36 million miles (58 million kilometres), Mercury is 0.4 astronomical units away from the Sun.
(I hope this helped ^^)
Chemistry Data Analysis --
7.86 x 10^-15 x 3.9 x 10^-10
Answer:
3.065 x 10^-24
Explanation:
hope this helps