Answer:
07.
Explanation:
Answer:
7
Explanation:
We call these different isotopes of nitrogen. There are always 7 protons because the nucleus is always a nitrogen nucleus (Z=7). Since different isotopes of an element have different numbers of neutrons (but always the same number of protons) they have different mass numbers.
Which of the following is a CHEMICAL CHANGE?
A- Buttering Toast
B- Melting ice Cream
C-An egg gives off a rotten smell
D-sugar is dissolved into water
E- baking soda mixed with vinegar forms bubbles
F- boiling water forms bubbles
G-Iron turns red as it rusts
H-Iron turns red as it is heated
Answer:
G, but I think that theres more than one answer
Fe (s) + Pb(NO3), (aq) —> ___
Type of reaction: _____
Answer:
lead , chemical
Explanation:
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.
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
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:
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).
How many molecules are in 210 grams of CO2?
Answer:
30 molecules
Explanation:
easy
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.
Can someone help me click the picture
Answer:
A product
B coefficient
C script
D rectant
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
Arrange the following in order of increasing atomic radius: Mg, Na, P, Si, and Ar.
Answer:
Ar, P, Si, Mg, Na
Explanation:
Ar=106pm
P=107pm
Si=111pm
Mg=141pm
Na=166pm
Na>Mg>Si>P>Ar is the order of increasing atomic radius.
What are elements?Elements are the simplest substances which cannot be broken down using chemical methods.
Atomic radii vary in a predictable way along or across the periodic table. The atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus we can say that helium is the smallest element, and francium is the largest.
Ar=106pm
P=107pm
Si=111pm
Mg=141pm
Na=166pm
Hence, Na>Mg>Si>P>Ar is the order of increasing atomic radius.
Learn more about elements here:
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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.
Help pls!! Due in 30 mins!
Which equation represents a single replacement reaction?
1. 2Al(s) + 3Cl2(g) → 2AlCl3(s)
2. 2Al(s) + 6HCl(aq) + 2AlCl3(aq) + 3H2(g)
3. 2AlCl3(s) → 2Al(s) + Cl2(g)
4. AlCl3(aq) + 3KOH(aq) + Al(OH)3(s) + 3KCl(aq)
2. 2Al(s) + 6HCl(aq) + 2AlCl3(aq) + 3H2(g) represents a single replacement reaction
Further explanationA single replacement reaction is a chemical reaction in which one element replaces the other elements of a compound to produce new elements and compounds
Not all of these reactions can occur. We can use the activity series(voltaic series), which is a list of elements that can replace other elements below / to the right of them in a single replacement reaction.
1. 2Al(s) + 3Cl2(g) → 2AlCl3(s)
Syntesis/combination reaction
2. 2Al(s) + 6HCl(aq) ⇒2AlCl3(aq) + 3H2(g)
Single replacement reaction
3. 2AlCl3(s) → 2Al(s) + Cl2(g)
Decomposition reaction
4. AlCl3(aq) + 3KOH(aq) + Al(OH)3(s) + 3KCl(aq)
Double replacement reaction
In a single replacement reaction, one element replaces another one. The reaction that shows the single replacement reaction is:
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
Single replacement reaction:It is a chemical reaction in which one element of the reactant compound replaces the other elements of another compound to form a new molecule.In these reactions, a more active element replaces the less active element.
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
In the given reaction, aluminum replaces the hydrogen from hydrochloric acid to form Aluminum chloride.
Therefore, the reaction that shows the single replacement reaction is:
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
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Which of the following is a true difference between protons and neutrons?
a
the have different masses
b
they are in different locations in the atom
c
the proton identifies the atom and the neutrons does not
d
all of the choices are true
Answer:
D
Explanation:
Chemistry, please help
Answer:
yeap this substance can conduct electricity
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:
What separation method collects vapor
Answer:
evaporation and distilation
Explanation:
Which of the following statements about elements and atoms is true?
Answer:
the first one
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]
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 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
Explain the saying, “Rome was not built in a day
Answer:
What is the Rome was not built in one day with speech
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)
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 :)
what is the needed electrons for CLO3-
Question: How hot is the sun?
Answer:
5,778 K
Explanation:
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:
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
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.
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