Mass number is the sum of protons and neutrons.
Atomic number is the total number of protons present.
Mass number = protons + neutrons
Atomic number = protons present.
From the above equations we can conclude that,
Atomic number= Mass number- neutrons.
Thus we can find out the atomic number by subtracting the number of neutrons from the mass number.
What is the conjugate base of H3PO4
Hey there!:
a conjugate base contains one less hydrogen atom and one more negative charge thant the acid that formed it . All acids have a conjugate base , all base have a conjugate acid, acids donate H⁺ when react.
Therefore:
H3PO4 -------------- H2PO4⁻
Hope that helps!
Which of the compounds above are strong enough acids to react almost completely with a hydroxide ion (pka of h2o = 15.74) or with a bicarbonate ion (pka of h2co3 = 6.37)? enter your answers as an alphabetized string, i.e. abc, not cba; enter none if none of the compounds are strong enough acids?
Pyridinium will react with both OH- and HCO3-, whereas the ketones will only react with concentrated OH-, while Butan-2-one cannot react with either of above.
a) Butan-2-one: cannot react with both hydroxide ion and bicarbonate.
b) Pyridinium: can react with both hydroxide ion and bicarbonate.
c) ketones : can only react with concentrated OH-
The mystery of periodic law was solved when __________ proposed his planetary atomic model of the atom, providing an understanding of the electronic structure of the elements and the organization of electrons into shells.
A) Bohr
B) Rutherford
C) Heisenberg
D) Schrödinger
Chris the Chemist was working in the lab, and he wanted to see what would happen if he put copper chloride into a Bunsen burner flame. As soon as he put it in the flame, it began to emit a green color. Which of these BEST describes this outcome?
A) The heat split the nucleus and created a new element.
B) As the copper chloride was heated, electrons were turned into neutrons.
C) As the electrons moved to a higher energy level, a photon of light is emitted.
D) When excited electrons return back to the ground state, a photon of light is emitted.
Boron has two naturally-ocurring isotopes. Boron-10 has an abundance of 19.8% and actual mass of 10.013 amu, and boron-11 has an abundance of 80.2% and actual mass of 11.009 amu. What is the average atomic mass for all isotopes of boron?
A) 10.0 amu
B) 10.5 amu
C) 10.511 amu
D) 10.812 amu
1. A) Bohr
2. D) When excited electrons return back to the ground state, a photon of light is emitted.
3. D) 10.812 amu
Hope this helps! :)
Answer:
1.A
2.D
3.D
Explanation:
1.We have to fill correct answer in blank space given in the question.
Bohr's postulates
1.Electron revolve in certain stable orbits around the nucleus without radiating any energy .The stable orbits or energy levels are called stationary orbits and these orbits at a certain discrete distance from the nucleus.
2.The stationary orbits are attained at distances for which the angular momentum is integral multiple of plank;s constant
L=mvr=nh
Where n is called principle quantum number
3.Electrons gain or lose energy when they jump from one energy lever to other energy lever or when higher energy level to low energy level.
Hence, the mystery of periodic laws was solved when Bohr proposed his planetary atomic model of the atom ,providing an understanding of the electronic structure of the elements and the organization of electrons into shells,
Option A is true.
2.When am electron absorb energy then the electrons jump from low energy level to high energy level .When the electron return from higher energy level to low energy level then it emit colored flame.
When Christ put copper chloride into Bunsen burner flame then it began to emit a green color because when excited electron returns back to the ground state , then photon of light is emitted.
Hence, option D is true.
3.Boron-10 has abundance 19.8% and actual mass of 10.013 amu and boron-11 has an abundance of 80.2% and actual mass of 11.009.
We have to find the average atomic mass for all isotopes of boron
Average atomic mass of boron =[tex]0.198\times 10.013+0.802\times 11.009[/tex]
Average atomic mass of boron=10.811792=10.812 amu
Hence, option D is true.
David is making lemonade he asked you could you some lemon juice and water the sugar starts to dissolve what can we do to speed up the dissolving process
We could (a) stir faster and (b) warm the mixture.
Stirring faster moves freshly-dissolved sugar away from the solid and allows new water molecules to contact with the surface,
Warming the mixture gives the water molecules more kinetic energy, so their collisions with the surface of the sugar will be more effective in removing the sugar molecules.
Which unit would be most appropriate for measuring the volume of water in a swimming pool? Liters or Kiloliters
The most appropriate for measuring the volume of water in a swimming pool is kilolitres.
Consider a pool that is 25 m long by 10 m wide with an average depth of 1.5 m.
V = lwh = 25 m × 10 m × 1.5 m = 375 m³
1 L = 1 dm³, so
V = 375 m³ × (10 dm/1 m)³ = 375 000 dm³ = 375 000 L = 375 kL
Thus, the cubic metre or kilolitre is more appropriate, because it gives more manageable numbers (i.e., between 0.1 and 1000)
Final answer:
The volume of water in a swimming pool is best measured in kiloliters due to the large amount of water pools hold, making it a more suitable and manageable unit than liters.
Explanation:
The most appropriate unit for measuring the volume of water in a swimming pool is kiloliters. When considering the size of a swimming pool and the large amount of water it holds, liters would be too small to effectively express this volume. Instead, using kiloliters, which represent thousands of liters, provides a more manageable and accurate measurement for such a substantial quantity of liquid.
It's important to select a unit that best corresponds with what is being measured. Since a swimming pool requires a significantly more substantial capacity for water compared to everyday containers, kiloliters are far more suitable than liters, which might be used for measuring smaller volumes, such as in a car's fuel tank. Hence, for the volume of a swimming pool, kiloliters are the ideal metric unit of capacity.
Soluble ionic compounds that dissociate naerly completely when dissolved are classified as _______.
A. Weak electrolytes
B. Insoluble
C. Dilute compounds
D. Strong electrolytes
The answer is D. Strong electrolytes
Strong electrolyte is a solute or solution that completely or almost completely dissociates when in solution. These are good conductors of electricity only when in molten/aqueous solution.
Strong electrolyte(aq) → Cation+(aq) + Anion−(aq)
If a plant produces 9.31 mol of C6H12O6, how many moles of H2O are needed?
Answer;
55.86 moles
Explanation;
Six molecule of H2O is needed for every molecule of C6H12O6 to be produced.
This means the ratio of H2O: C6H12O6 is 6:1
Let H2O mole= X
Therefore...
X/9.31 = 6/1
X= 6 x 9.31
X = 55.86 moles
55.86 moles of H2O are needed to produce 9.31 moles of C6H12O6.
How to get the chemical formulaThe chemical formula for glucose (C6H12O6) indicates that there are 6 moles of water (H2O) needed for every mole of glucose produced. Therefore, to find out how many moles of water are needed for 9.31 moles of glucose (C6H12O6), you can multiply the number of moles of glucose by the ratio of moles of water to moles of glucose:
Number of moles of H2O = Number of moles of C6H12O6 × (6 moles of H2O / 1 mole of C6H12O6)
Number of moles of H2O = 9.31 moles × 6
Number of moles of H2O = 55.86 moles
So, 55.86 moles of H2O are needed to produce 9.31 moles of C6H12O6.
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(30 points) What is the relationship between the atomic numbers and atomic radii of the elements in the group? Propose an explanation for this relationship? Is this consistent with the periodic trends you’ve learned about?
**y is atomic radius and x is atomic number**
The relationship is r = 2.5Z + 130.
From your graph, I estimate the slope of the line to be:
[tex]\text{slope} = \frac{\Delta y }{\Delta x } = \frac{260-130}{56-4} = \frac{130}{52} = 2.5\\[/tex]
The y-intercept ≈ 130.
So, the equation for the line is
r = 2.5Z + 130.
The relation tells us that the atomic size increases as the atomic number increases.
This makes sense because, as you go down a Group, you are adding electrons to the next shell further out.
When entering coefficients to balance equations, recall that just writing the symbol implies "1." Therefore, if a coefficient of "1" is required, choose "blank" for that box. Balance the following reaction. MgCl2 + AgNO3 → AgCl + Mg(NO3)2
The balanced equation is MgCl₂ +2AgNO₃ ⟶ 2AgCl + Mg(NO₃)₂
Step 1. Start with the most complicated-looking formula [Mg(NO₃)₂].
Put a 1 in front of it and balance its atoms.
MgCl₂ +AgNO₃ ⟶ AgCl + 1Mg(NO₃)₂
Step 2. Balance Mg.
1MgCl₂ +AgNO₃ ⟶ AgCl + 1Mg(NO₃)₂
Already balanced —1 atom each side.
Step 3. Balance N.
We have 2 N on the right-hand side and 1 N on the left. We need 2 N on the left. Put a 2 in front of AgNO₃.
1MgCl₂ +2AgNO₃ ⟶ AgCl + 1Mg(NO₃)₂
Step 4: Balance O
Done. We have 6 O on the left and 6 O on the right.
Step 5. Balance Ag.
We have 2 Ag on the left, so we need 2 Ag on the right. Put a 2 in front of AgCl.
1MgCl₂ +2AgNO₃ ⟶ 2AgCl + 1Mg(NO₃)₂
The balanced equation is
MgCl₂ +2AgNO₃ ⟶ 2AgCl + Mg(NO₃)₂
Answer:
1,2,2,1
Explanation:
Jamie hears a high-pitch sounds that then charges to a low pitch sound what is most likely occurring
Assuming that the source generates pitch at a constant frequency, the source is likely to be continuously moving away from Jamie the observer.
Doppler Shift describes the observation that relative movements between the source and receiver would alter the apparent wavelength of both acoustic and electromagnetic radiation.
Waves from a source moving towards an observer are compressed. A stationary observer would find the wavelength shorter and hence the frequency higher than they actually are at the source. Similarly, waves coming from a retreating source are stretched and experience an apparent decrease in frequency.
A low-pitch corresponds to a low vibration frequency and hence long wavelength. The observation that wavelength appears to be increasing corresponds to the scenario that sound waves are being stretched when there's an increase in the separation between the source and the observer.
How many oxygen atoms are in 10 formula units of AI2(SO4)3
Answer:
120 Oxygen atomsData given
Formula unit of AL2(SO4)3 =101 formula unit of AL2(SO4)3 contain oxygen atoms = 1210 formula unit of AL2(SO4)3 contain oxygen atoms = 12 × 10 1 formula unit of AL2(SO4)3 contain oxygen atoms = 120there are 120! because:
04 multiplied by 3 to make 12,
and since there are 10 units,
you multiply 12 by 10,
you get 120 oxygen atoms!
Name the type of crystalline solid formed from the following structural units and describe how the solid is formed.
A. Metal atoms
B. Nonmetal atoms
Metal atoms form metallic solids whose properties stem from positively charged metal ions embedded in a sea of delocalized electrons. Nonmetal atoms typically form covalent network solids which are continuous networks of nonmetal atoms bonded by covalent bonds.
Explanation:The type of crystalline solid formed from Metal atoms is called metallic solid. Metallic solids are formed when positively charged metal ions are embedded in a sea of delocalized electrons leading to strong metallic bonding and a regular packed structure. The properties of metallic solids such as heat and electrical conductivity malleability and ductility are due to this arrangement.
On the other hand the type of crystalline solid formed from Nonmetal atoms generally forms covalent network solids. These are formed when nonmetal atoms are bonded together through covalent bonds in a continuous network. Diamonds (carbon atoms) and quartz (silicon and oxygen atoms) are examples of covalent network solids.
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Explain how you can use Boyle's law to determine the new volume of gas when it's pressure is increased from 170 to 5:40 the original volume of gas is one leader assume the temperature and number of particles are consistent what is the new volume
The Boyle's Law states an inverse relationship between the pressure of a gas and its volume when its temperature stays constant.
For the question
Initial Volume [tex]V_1 = 1 \; \text{L}[/tex]Initial Pressure [tex]P_1 = 170[/tex]Final Pressure [tex]P_2 = 540[/tex][tex]T_1/T_2 = P_1/P_2[/tex]
Thus
[tex]V_2 = V_1 \cdot (P_1 / P_2) = 0.315[/tex]
A sample of an ideal gas is cooled from 50.0 degrees celsius to 25.0 degrees celsius in a scaled container of constant volume. Which of the following values for the gas will decrease?
1. The average molecular mass of gas.
2.The average distance between the molecules.
3. The average speed of molecules.
Answer: 3- The average speed of the molecules would reduce.
It has been mentioned that the container in which the ideal gas is cooled from 50 degree Celsius to 25 degree Celsius has constant volume. Since the volume of the container is constant, the molecular mass would remain the same. Also since the volume is constant even though the gas is cooled down,the average distance between the molecules would remain the same.
Since the temperature is reduced from 50 degree Celsius to 25 degree Celsius, the movement and the kinetic energy associated with the gas molecules would reduce. Hence the average speed of the molecules would reduce.
How many grams of a 1000-gram radioactive sample are left after 3 half-lives?1000 grams 500 grams 250 grams 125 grams 2000 grams
The answer is 125 gms.
Help!!!! How are the properties and safety concerns of these two chemicals Barium Sulfate and Barium sulfide different? Are they similar?
Barium Sulfate [tex]\text{BaSO}_4[/tex] is chemically stable and safe for human consumption.
Barium Sulfide [tex]\text{BaS}[/tex] is toxic and shall be handled with care.
ExplanationBarium ions [tex]\text{Ba}^{2+}[/tex] ions can damage cell membranes and are thus toxic to the human body.
Barium ions in barium sulfate, however, are held tightly in ionic lattice and barely dissolve in water. Barium sulfate thus stay intact and give rise to no harmful [tex]\text{Ba}^{2+}[/tex] ions when orally ingested.
Barium sulfide can dissolve in water at significant quantities to produce barium [tex]\text{Ba}^{2+}[/tex] ions and sulfide [tex]\text{S}^{-2}[/tex] ions. Barium ions are toxic aforementioned whereas sulfide ions can undergo hydrolysis to produce hydrogen sulfide, a weak acid that evolves and behaves as a toxic gas.
[tex]\text{BaS} \; (s)\to\text{Ba}^{2+} \; (aq) + \text{S}^{2} \; (aq)\\\text{S}^{2-}\; (aq) + 2\; \text{H}_2\text{O} \; (l) \rightleftharpoons \text{H}_2\text{S} \; (g) + 2 \; \text{OH}^{-} \; (aq)[/tex]
How do earthquakes happen ?
A. Because of a release of pressure from plate movement
B. Only because of a volcanic eruption
C. Because of motion of ocean waves
D. Only because of a lack of pressure between plates
it is A. Because of a release of pressure from plate movement
It’s A. Because the tectonic plates move by the movements of the earths crust
An aqueous solution contains the following ions: Cl-, K+, Mg{2+}, NO3{-}, SO4{2-}. Is a precipitate likely to form? If so, giv ethe formula of the precipitate.
A. MgSO4
B. MgCl2
C. K2SO4
D. No precipitate will form.
D. No precipitate will form.
You must recall the pertinent solubility rules:
Salts of Group 1 elements (K⁺) are soluble. Salts containing nitrate ion (NO₃⁻) are soluble. Salts containing chloride ion (Cl⁻) are generally soluble. Most sulfate (SO₄²⁻) salts are soluble.The only ion not included in the list is Mg²⁺.
However, according to the rules, Mg(NO₃)₂, MgCl₂, and MgSO₄ are soluble.
Thus, there is no precipitate.
According to solubility rules, no precipitate is expected to form from the ions listed in the question (Cl-, K+, Mg²⁺, NO³⁻, SO₄²⁻), the correct answer is D. No precipitate will form.
To determine if a precipitate will form in an aqueous solution containing Cl-, K+, Mg²⁺, NO³⁻, SO₄²⁻, we should apply the solubility rules for ionic compounds. MgSO₄ and K₂SO₄ are generally soluble (Sulfates are generally soluble except for those of barium, calcium, and lead).
MgCl₂, being composed of a Group 2 cation and the chloride anion, is also soluble. However, we must check for the potential formation of a hydroxide precipitate, since that was not explicitly excluded in the original question. Given that hydroxides are typically insoluble except for those of alkali metals and some Group 2 metals (Ca, Sr, and Ba), if hydroxide ions were present, one could expect to see a precipitate of Mg(OH)₂.
However, since the question does not provide information about the presence of hydroxide ions in the solution, and based on the ions listed, no precipitate is expected according to the solubility rules. Therefore, the correct answer is D. No precipitate will form.
Draw the electric field lines between two negatively charged particles. According to Coulomb's law, how would the electrical force between these particles change if they were moved farther apart?
Here we have to draw the electric field between two negatively charged particles and the effect of distance on it have to discuss.
The electric field between the two negatively charged particle are shown in the figure. There will be repulsion between the same charge particle. As the distance between the charged particle increases the force of repulsion will decreases.
The force of attraction between two charged particle was described by Coulomb, which is known as coulomb's inverse square law.
As per the law the force of attraction or repulsion between two charged particles is proportional to the multiplication of the charge and inversely proportional to the square of the distance between the particles.
Mathematically it can be represented as -
the force F ∞ q₁ × q₂ (q is the charge of the particles) and F ∞ [tex]\frac{1}{r^{2} }[/tex] (r is the distance between the two charge particles)
By combining F ∞ [tex]\frac{q_{1}q_{2}} {r^{2} }[/tex]
Or, F = ∈⁻¹ [tex]\frac{q_{1}q_{2}} {r^{2} }[/tex] (where ∈ = permittivity of the medium)
Thus as per the law as the distance (r) increases the force of repulsion between the two negatively charged particle will increase.
Thus the electric field between two negative charge particle is shown and the effect of distance on it explained.
As the distance [tex](\text{r})[/tex] increases the force of repulsion between two charged particle will increase.
Explanation:
Given information:
The electric field line is drawn between two negatively charged particle.
Now, as we know
According to coulomb's law, the force of attraction or repulsion between two charged particle is proportional to the product of the charge and inversely proportional to the square of the distance between the particles.
As:
[tex]F = k. (q_1.q_2)\\F=k.(1/r^2)\\[/tex]
Where [tex]k[/tex] is the permittivity of the medium.
Now, according to the law as the distance increases the force of repulsion between two charged particle will increase.
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