Answer:
Based on the periodic law
Explanation:
All the elements on the periodic table were constructed based on the periodic law.
Henry Moseley in the 1900s re-stated the periodic law by changing the basis of the law from atomic weight to atomic number. The present periodic law is therefore "the properties of elements are a periodic function of their atomic number".
The atomic number is the number of protons in an atom. Based on the graduation of atomic number on the periodic table, elements are classified into groups and periods.The system brings molecules to the cells. It includes blood vessels and the heart.
respiratory system
digestive system
circulatory system
nervous system
Which of the following statements about elements and atoms is true?
Answer:
the first one
Explanation:
What is evidence that a chemical change has happened?
O A. The temperature of a substance increases or decreases.
B. The amount of matter increases.
C. A substance changes into a new kind of substance.
O D. You observe a color change.
The temperature of the water vapor (H,0) inside a pressure cooker increased from 295 K to 395 K. AS
the sample is heated, the pressure of the water vapor went from 21.0 kPa to
Answer:
P₂ = 28.12 KPa
Explanation:
Given data:
Initial temperature = 295 K
Final temperature= 395 K
Initial pressure = 21.0 KPa
Final pressure = ?
Solution:
According to Gay-Lussac Law,
The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.
Mathematical relationship:
P₁/T₁ = P₂/T₂
Now we will put the values in formula:
21.0 KPa / 295 K = P₂/395 K
P₂ = 21.0 KPa× 395 K / 295 K
P₂ = 8295 KPa. K /295 K
P₂ = 28.12 KPa
Which of these is not true about weight
A:it is measurement of how heavy an object is
B:it is always the same mass,regardless of gravity
C:it is affected by objects mass and the force of gravity
D:it’s is commonly measured in pounds
Answer:
its b beacuse different things have different mass
Fe (s) + Pb(NO3), (aq) —> ___
Type of reaction: _____
Answer:
lead , chemical
Explanation:
Which three statements about forces are true?
A. Some forces cause objects around us to move,
B. Force can cause changes in the motion and energy of matter,
C. Every force can be identified as one of the fundamental forces,
D. Force is the ability to change motion and transfer matter,
E. Some forces keep objects around us from moving,
Answer:
A. Some forces cause objects around us to move,
C. Every force can be identified as one of the fundamental forces,
D. Force is the ability to change motion and transfer matter,
Explanation:
Force basically is defined as pull or push on a body. Forces are known to cause the change in motion of a body as the amount of force applied is attenuated.
Every known force in the universe can be traced to the four fundamental forces which are gravitational force, electromagnetic, strong and weak forces. Force enables a body to change its motions by acceleration.A 200.0-mL sample of helium gas is in a cylinder with a movable piston at 110 kPa and 275 K. The piston is pushed in until the sample has a volume of 95.0 mL. The new temperature of the gas is 310. K. What is the new pressure of the sample?
51.1 kPa
261 kPa
249 kPa
274 kPa
Answer:
P₂ = 261 KPa
Explanation:
Given data:
Volume of sample = 200 mL
Initial pressure = 110 KPa
Initial temperature = 275 K
Final volume = 95 mL
Final temperature = 310 K
Final pressure = ?
Solution:
Formula:
P₁V₁/T₁ = P₂V₂/T₂
P₂ = P₁V₁T₂ /T₁ V₂
P₂ = 110 KPa× 200 mL× 310 K /275 K × 95 mL
P₂ = 6820000 KPa / 26125
P₂ = 261 KPa
Please help meee! It would be awesome if you can!
Answer:
3) the north Pacific Ocean
Explanation:
Maritime polar air is defined officially as: Maritime polar (mP) air masses are cool, moist, and unstable. Some maritime polar air masses originate as continental polar air masses over Asia and move westward over the Pacific, collecting warmth and moisture from the ocean
Basically it's the North Pacific Ocean because of the higher latitude and colder air temperature
Which is most likely the result of millions of metal atoms crowding together so that molecular orbitals become combined?
The formation of bands in a crystal
Explanation:
- hope that helped :)
Question: How hot is the sun?
Answer:
5,778 K
Explanation:
help which is the right answer
Answer:
936g/mol
Explanation:
To find the molar mass of a molecule, you find the sum of the molar masses of each atom in the molecule.
This compound has 40 carbon atoms, 60 Hydrogen atoms, 10 Nitrogen atoms, 12 Oxygen atoms, and 2 Sulphur atoms.
The molar mass of:
Carbon is 12g/molHydrogen is 1g/molNitrogen is 14g/molOxygen is 16g/molSulphur is 32g/mol[tex](12 \times 40) + (60 \times 1) + (14 \times 10) + (16 \times 12) + (32 \times 2) = 936[/tex]
C - chemical change
P- physical change
(Pls help me)
Answer:
Burning wood is a chemical change. Burning wood is an example of a chemical reaction in which wood in the presence of heat and oxygen is transformed into carbon dioxide, water vapour, and ash.
Baking an apple pie is a physical change because the apples in the pie start changing physically and the pie crust starts hardening and rising up.
Explanation:
Conversion factor 1 calorie (kicalorie) = 1000 calories
Answer:correct
Explanation:
The large calorie, food calorie, or kilocalorie (Cal, calorie or kcal) is the amount of heat needed to cause the same increase in one kilogram of water. Thus, 1 kilocalorie (kcal) = 1000 calories (cal).
What Happens When extra Solute is added to unsaturated ,saturated and supersaturated solution
of water is 36.0 g. If any more NaCl is added past that point, it will not dissolve because the solution is saturated. If more solute is added and it does not dissolve, then the original solution was saturated. If the added solute dissolves, then the original solution was unsaturated.
What type of stress occurs when a rock mass is pushed in opposite directions?
Answer:
Shear stress
Explanation:
Answer:
C-Shearing
Explanation:
Shearing is a type of stress caused when a rock mass is pushed in opposite directions Rocks break and split apart and change shapes. Shearing is common at transform boundaries
What is the product of the synthesis reaction between calcium and iodine?
Answer:
The product of the synthesis reaction is CaI.
Explanation:
In chemistry, chemical equations are the representation of chemical reactions between elements, compounds, substances, or molecules.
They are written using element symbols (and sometimes including their current state of matter).
Therefore, if we wanted to show the reaction of sodium and chlorine to make sodium chloride, or table salt, we would illustrate it as such:
[tex]\bullet \ \text{Na + Cl} \rightarrow \text{NaCl}[/tex]
A synthesis reaction in chemistry is the combination of two or more elements, compounds, molecules, or substances to make one compound, molecule, or substance.
The parent equation for a synthesis reaction is:
[tex]\bullet \ \text{A + B}\rightarrow \text{AB}[/tex]
Therefore, we need to find out what the element symbols are for both calcium and iodine.
If we reference a periodic table, we will see that calcium is atomic number 20 and has the symbol Ca.
Additionally, when we locate iodine, we will see that it is atomic number 53 and has the atomic symbol I.
Now, we just need to create the reaction equation.
[tex]\text{Ca + I}\rightarrow \text{?}[/tex]
We know that we are dealing with a synthesis reaction, or a combination, so the elements will combine to make one substance.
With this information, we can make an equation:
[tex]\text{Ca + I} \rightarrow \text{CaI}[/tex]
Therefore, the product of the synthesis reaction is CaI.
Note: Please note that "I" is an uppercase i.
Describe the two types of mechanical energy
Answer:
Kinetic energy and potential energy
Explanation:
kinetic energy is when the energy is active and potential energy is when it is about to be active
write the correct representation of an element x which contains 12 electrons and 16 neutrons
Answer:
²⁸Mg
Explanation:
12 electrons means it is a Mg;
A typical Mg has 12 neutrons, but this has 16 hence it must be an isotope with 4 extra neutrons.
Chemistry, please help
Answer:
yeap this substance can conduct electricity
Explain the saying, “Rome was not built in a day
Answer:
What is the Rome was not built in one day with speech
Ella makes this table to organize her notes on whether atoms gain or lose energy during the changes of state.
A 2-column table with 2 rows. The first row has entries Gain Energy, Lose Energy. The second row has entries nothing, nothing.
Which changes of state should she place in the column titled "Lose Energy"?
freezing, boiling, and melting
melting, vaporization, and sublimation
sublimation, deposition, and condensation
freezing, deposition, and condensation
Answer:
D
Explanation:
I took the test
Answer:
D took the test
Explanation:
what is the physical state of the fuel in a lighter?why happens if you press the lighter in order to let the fuel to flow out
Answer:
It is a liquid gas
Explanation:
The spark of the lighter starts the fire which is exposed to the liquid gas in the lighter
7. Calculate the average atomic mass of bromine. One isotope of bromine has an atomic mass of 78.92amu and a relative abundance of 50.69%. The other major isotope of bromine has an atomic mass of 80.92amu and a relative abundance of 49.31%.
Answer:
Average atomic mass = 79.9 amu.
Explanation:
Given data:
Average atomic mass of Bromine = ?
Atomic mass of 1st isotope = 78.92 amu
Relative abundance of 1st isotope = 50.69%
Atomic mass of 2nd isotope = 80.92 amu
Relative abundance of 1st isotope = 49.31%
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (50.69×78.92)+(80.92×49.31) /100
Average atomic mass = 4000.45 + 3990.16 / 100
Average atomic mass = 7990.61 / 100
Average atomic mass = 79.9 amu.
which is not a redox reaction?
a. Formation of ammonium sulphate from ammonia and sulphuric acid
b. formation of nitrogen monoxide from ammonia
c. formation of sulphuric acid from sulphur
d. formation of zinc from zinc sulphide
help me please
Answer:
D. formation of zinc from zinc sulphide
Explanation:
A redox reaction could be explained as an artificial reaction in which electrons are moved between two reactants partaking in it. This substitution of electrons can be recognized by examining the variations in the oxidation states of the reacting classes. The generation of hydrogen fluoride is an illustration of a redox reaction. We can crack the reaction down to investigate the oxidation and loss of reactants.
what is the needed electrons for CLO3-
Calculate the number of moles of Na+ ions in 25g of sodium carbonate?
Explanation:
First, we need to calculate the number of moles of sodium carbonate we have in a 25 g sample. To calculate this, we will
find the molar mass of sodium carbonate (Na2CO3):
⇒ 2 × Molar mass of sodium + Molar mass of carbon + 3×molar mass of oxygen
⇒ 2 × 23 + 12 + 3 × 16
⇒ 46 + 12 + 48
⇒ 106g/mol
Thus, the molar mass of Na2CO3 is 106g/mol.
Therefore, number of moles = 25 ÷ 106
=> 0.2358 mol
Now, we know that every mole of Na2CO3 have 0.2358 moles of Na+ ions. Hence, total moles of Na2CO3 is 0.4716 moles
Number of ions present = 6.022 × 1023 × 0.4716 mol = 2.84 × 1023ions
The molar mass of sodium carbonate is 106 g/mol. One mole of sodium carbonate gives 2 Na+ ions. Thus number of moles in 25 g of sodium carbonate is 0.47 moles.
What is sodium ions?Sodium ion Na+ is formed by the lose of one electron from the sodium metal. Sodium has one valence electron and it will reacts with other atoms by donating this electron and gaining a positive charge.
The molecular formula of sodium carbonate is Na₂CO₃. Therefore, one mole of sodium carbonate will give two moles of Na+ ions. The molar mass of sodium carbonate is 106 g/mol.
The number of moles of 25 g of sodium carbonate is calculated as follows:
Number of moles = 25 /106
= 0.235 moles.
It is clear that one mole of Na₂CO₃ gives two moles of sodium ions.Then, number of moles of sodium ions given by 0.235 moles of sodium carbonate is calculated as follows:
number of moles of Na+ = 0.235 × 2
= 0.47 moles
Hence, the number of moles of Na+ ions produced by 25g of sodium carbonate is 0.47 moles.
To find more about sodium carbonate, refer the link below:
https://brainly.com/question/28901831
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What is the role of CdKs? to create enzymes that produce chemical changes to signal the cell to move to the next phase of the cell cycle to build structural components of DNA and energy-rich substances to activate the cyclins that cause progression of the cell cycle
Answer:
It’s b
Explanation:
Answer:
Regulation of the cell cycle is carried out by which of the following? Check all that apply.
CdKs
cyclins
What is the role of CdKs?
to signal the cell to move to the next phase of the cell cycle
Explanation:
How many molecules are in 210 grams of CO2?
Answer:
30 molecules
Explanation:
easy
Which is most likely the result of millions of metal atoms crowding together so that molecular orbitals become combined?
Answer:
(The Formation Of Bands In A Crystal)