Answer:
All the elements of a group have similar chemical properties because they have same no. of valence electrons in their outermost shell.
All the elements of a period have different chemical properties because they have different no. of valence electrons in their atoms.
Answer:
4
Explanation:
Same group elements have the same physical properties and same elements in period have same chemical properties
If 12.2 kg of Al2O3(s), 57.4 kg of NaOH(l), and 57.4 kg of HF(g) react completely, how many kilograms of cryolite will be produced?
Explanation:
Write the balanced equation
Let's start off by writing the reaction for the formation of cryolite:
Al₂O₃ + 6NaOH + 12HF → 2Na₃AlF₆ + 9H₂O
Determine the limiting factor
moles = mass ÷ molar mass
moles of Al₂O₃ = 12200 g ÷ 101.96 g/mol = 119.65 mol
moles of NaOH = 57400 g ÷ 39.997 g/mol = 1435.11 mol
moles of HF = 57400 g ÷ 20.01 g/mol = 2868.57 mol
Since Al₂O₃ has the smallest number of moles in the reaction, it is the limiting factor. As such we will have to use the moles of Al₂O₃ to determine the moles of cryolite that will be produced.
Find the mole ratio between the limiting factor and the cryolite
The mole ratio of Al₂O₃ : Na₃AlF₆ based on the balanced equation is 1 : 2
∴ since the moles of Al₂O₃ = 119.65 mol
the moles of Na₃AlF₆ = 119.65 mol × 2 = 239.3 mol
Calculate the mass of the Cryolite
Mass cryolite = moles × molar mass
= 239.3 mol × 209.9 g/mol
= 50229.07 g
∴ kilograms of cryolite ≈ 50.23 kg
A flagpole is an example of what type of pulley system?
A. Movable pulley
B. Fixed pulley
C. Block and tackle?
Answer:
B
Explanation:
i learned the pulley system in school
Answer:
B. Fixed pulley
Explanation:
if the reactants of a reaction have an initial mass of 25g what should the mass of the products be
Answer:
It remains the same
Explanation:
The law of conservation of mass states that, during a chemical reaction, the total mass of the products must be equal to the total mass of the reactants.
The trend towards smaller atomic radii as one moves to the right in a period is _____. A) faulty, as atomic radii in a period are nearly uniform in size. B) because of electron pair repulsion causing the expansion of the orbitals. C) wrong. Atomic radii increase across a period left to right as the larger d and p orbitals are occupied after the s orbital. D) due to the effective nuclear charge decreasing. E) due to the effective nuclear charge increasing.
Answer:
It’s E. Nuclear charge increasing
Explanation: it just is
There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Option E is correct option.
What is periodic table?Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.
As we go from left to right in periodic table the atomic radii decreases because of increase in effective nuclear charge . There is no increase in number of shells only the number of electrons increases which increase the number of protons in the nucleus and hence the effective nuclear charge of the atom which makes the size of atom contract.
Therefore, the trend towards smaller atomic radii as one moves to the right in a period is due to the effective nuclear charge increasing. The correct option is option E.
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Phản ứng nào sau đây chuyển glucozơ và fructozơ thành một sản phẩm duy nhất?
A. Phản ứng với Cu(OH)2, t0. B. Phản ứng với dung dịch AgNO3/NH3. C. Phản ứng với H2/Ni, t0. D. Phản ứng với Na.
Answer:
Aaaaaaaaaaaaaaaassplee
A dry soil sample has a volume of 500 mL. After 400 mL of water are added to the soil, the soil becomes saturated with 150 mL of surface water left on top. What is the porosity of the soil?
Please help me
What type of chemical reaction is this?
Answer:
OXIDATION/REDUCTION
Explanation:
Ba has been transformed from a neutral atom to a +2 ion
O has been transformed from a neutral atom to a -2 ion
HELPPP PLZZZ ASAPPPPPO
Answer:
0.000471698
Explanation:
divide 0.125 by 265.
What is the resultant force of a motorcycle travelling at 500 N with an air resistance of 50 N
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The resultant force is equal to :
[tex]500 - 50[/tex][tex]450 \: \: N[/tex]Which ion has a smaller size,1)N---,O--,F-and Ne 2) Cl-,Br- and I ?Why
Help me to solve it!
Answer:
nitrogen because it has less number of protons and electrons, thus a samller atomic mass
Explanation:
Explanation:
Ne have smaller size because Ne have no negative charge compare to N, O and F which negative charge depends on size of an atom, Therefore more the negative charge , more will be the size of atom.Cl- have smaller size because as we go down the group, Size of the atom increase as Cl<Br<I irrespective to the atomic charge8. Explain why fluorine has a smaller atomic radius than chlorine.
Answer:
Explanation: Fluorine has a smaller atomic radius than oxygen because fluorine has a larger nuclear charge. Fluorine has a smaller radius than chlorine because it has eight fewer electrons.
There are various kind of elements that are present in periodic table. Some elements are harmful, some are noble gases. The size difference between chlorine and fluorine can be explained on the basis of number of shells.
What is periodic table?Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.
As we go down along the periodic table the number of shells increases.
Atomic number of F= 9
Electronic configuration of F=2, 7
Atomic number of Cl= 17
Electronic configuration of chlorine = 2,8,7
So, there are total 2 shells in Fluorine while chlorine has 3 shells. The distance of shells increases with increase in number of shells. This makes the size of chlorine more bigger than fluorine.
Therefore, the size difference between chlorine and fluorine can be explained on the basis of number of shells.
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Please help!
Answer please!
Answer: a
Explanation: a
What was John Dalton's contribution to the development of the atomic theory?
A
Dalton recognized that tiny atoms combined to form complex structures.
B
Dalton recognized the presence of electrons around a nucleus.
C
Dalton recognized the presence of protons in the nucleus.
Answer:
A. Dalton recognized that tiny atoms combined to form complex structures.Which of the following is the source of energy for nuclear energy?
Select one:
O a. Nuclear fusion
O b. Nuclear fission
OC. Nuclear Inclusions
O d. Nuclear Reactions
Answer:
b. Nuclear fission
Explanation:
The types of projection that are useful for making maps of the United States are called __________. (Choose 2)
Answer:
Mercator projection, geologic projection
Why are engineers called applied scientist?
Answer:
Applied science is a discipline that is used to apply existing scientific knowledge to develop more practical applications, for example: technology or inventions. In natural science, basic science (or pure science) is used to develop information to explain phenomena in the natural world.
Answer:
• Because engineers apply science and its theories into practical situation
Take an example of;
→ A generator: When creating a generator, electromagnetic induction theorem is applied. [ self and mutual inductance ]
→ A plane: The wings are made in considerance of Bernoulli principle and viscous drag
[tex].[/tex]
Velocity has both speed and direction, so it is a what
Answer: Velocity is a mathematical vector. That means it has both a magnitude (speed) and a direction. Scientists need to consider an object’s velocity to calculate its momentum — its velocity multiplied by its mass. Scientists use measures of velocity in everything from figuring out how much rain is falling to sending a rocket to space.
Explanation: Hope this help:)
Which is a valid velocity reading for an object?
45 m/s
45 m/s north
0 0 m/s south
0 m/s
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Sunt
Mark this and retum
iii. According to the law of conservation of energy, what can change? (1 point) FAKES WILL BE REPORTED I EILL GIVE U BRAINLIEST
Answer:
Nothing can change because energy can't be made or destroyed
Explanation:
Name and Title:
Include your name, instructor's name, date, and name of lab.
Objectives(s):
In your own words, what is the purpose of this lab?
Hypothesis:
In this section, please include the if/then statements you developed during your lab activity. These statements reflect your predicted outcomes for the experiment.
Procedure:
The materials and procedures are listed in your virtual lab. You do not need to repeat them here. However, you should note if you experienced any errors or other factors that might affect your outcome. Using your summary questions at the end of your virtual lab activity, please clearly define the dependent and independent variables of the experiment.
Data:
Record the composition of each of your compounds below. Be sure to include the number of atoms for each element. An example has been supplied for you.
Compound Name Chemical Formula Sodium (Na) Atoms Calcium (Ca) Atoms Hydrogen (H) Atoms Oxygen (O) Atoms Carbon (C) Atoms Chlorine (Cl) Atoms
Ex: Sodium
hypochlorite NaClO 1 0 0 1 0 1
Conclusion:
Your conclusion will include a summary of the lab results and an interpretation of the results. Please answer all questions in complete sentences using your own words.
Using two to three sentences, summarize what you investigated and observed in this lab.
Why do you believe knowing how elements and compounds react together is essential in everyday matters?
Some elements are more "reactive" than other elements; why do you think this is?
Choose one of the compounds from the table and explain how you know the numbers of atoms in your formula.
Is it possible for two different compounds to be made from the exact same two elements? Why or why not? With a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?
Answer:
I dont know your intructors name also do this yourself we dont know what the lab is
Explanation:
If repeated measurements agree closely but differ widely from accepted value these measurements are?
d. precise, but not accurate
What mass of glucose would you need (in g) to have 0.8 mol, given that the molar mass of glucose is 180 g mol-1?
Explanation:
Mass of glucose = moles × molar mass
∴ Mass of glucose = 0.8 mol × 180 g mol⁻¹
= 144 g
∴ the mass of glucose you need to have 0.8 mol of glucose = 144 g
LIST TWO REASONS WHY WE SHARE OUR RESULTS A SCIENTIFIC INVESTIGATION
Publishing results of research projects in peer-reviewed journals enables the scientific and medical community to evaluate the findings themselves. It also provides instructions so that other researchers can repeat the experiment or build on it to verify and confirm the results.
In a varve, summer is represented by _____.
sediment from melting glaciers being deposited in lakes
clay from wind-blown dust
ash from nearby volcanoes
None of these
Answer:
answer b
Explanation:
i took the test
Answer:
Hey let's talk here if you want
For X + Y → XY, if [XY] is increasing at a rate 0.10 M s-1, predict the rate of depletion of both reactants.
what is daltons theroy
Answer:
A theory of chemical combination, first stated by John Dalton in 1803. It involves the following postulates: (1) Elements consist of indivisible small particles (atoms). (2) All atoms of the same element are identical; different elements have different types of atom. (3) Atoms can neither be created nor destroyed.
Explanation:
BaCO3(s) → BaO(s) + CO2(g)
(a) A student heated a 10.0 g sample of barium carbonate until it was fully decomposed.
(i) Calculate the number of moles of barium carbonate the student used.
moles of barium carbonate =
number of moles = mass
molar mass
BaCO3 molar mass = 197.34 g/mol
mass = 10g
n = 10/197.34
n = 0.05moles.
The number of moles of barium carbonate used are 0.05moles.
. What is the total number of protons, neutrons,
and electrons in a cadmium, Cd, atom that has
a mass number of 112?
PLEASE I NEED HELP
Answer:
# of Proton: 48
# of Electron: 48
# ofNeutron: 64
Explanation:
The atomic number of cadmium is 48.
∴ atomic number = protons = electrons = 48.
Neutrons = mass number - atomic number
∴ Neutrons = 112 - 48 = 64.
⇒ number of protons= 48; neutrons= 64; electrons=48
WILL MARK AS BRAINLIEST IF CORRECT
The temperature of an enclosed gas at constant pressure changes from 400 K to 100 K atm. What happens to the volume of the gas?
a
The volume will increase to 4 times its original volume.
b
The volume will stay the same.
c
The volume will decrease to 1/2 of its original volume.
d
The volume will decrease to 1/4 of its original volume.
e
The volume will increase to 2 times its original volume.
Answer:
a
Explanation:
they are directly proportional. if one goes down the other goes up while pressure is constant
Can someone help please?
Copper occurs naturally as a mix of two isotopes: Copper-63 with a mass of 62.930 amu and copper-65 with a mass of 64.928 amu. The percent abundance of copper-63 is 69.09%.
Calculate the atomic mass of copper.
Answer: 63.55
Explanation:
The attached chart shows the calculation. The orange line points to the % abundance of Cu-65, which is the difference of 100% less the % Abundance of Cu-65 (since there are only 2 isotopes).
The weighted average contribution of each istope is calculated (blue arrow) and then summed to find the atomic mass of copper.