John Dalton’s atomic model described atoms as the smallest indivisible part of an element.
What are atomic models?Atomic models are models which are used to represent the structure of the atom.
Different scientists put forward different models to represent the atom.
One of the scientists was John Dalton.
The features of Dalton's atomic model includes:
atoms are the smallest particle of elements atoms are indivisible atoms of the same element were the same and atoms if different elements differed in all aspectsTherefore, John Dalton’s atomic model described atoms as the smallest indivisible part of an element.
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If 33.9 ml of h3po4 neutralizes 23.4 ml of 2.28 m koh, what is the molarity of the phosphoric acid?
Answer: 1.57 M
Explanation:
[tex]M_{A}V_{A}=M_{B}V_{B}\\(33.9)M_{A}-=(23.4)(2.28)\\M_{A}=\frac{(23.4)(2.28)}{33.9}=\boxed{1.57 \text{ M}}[/tex]
In a mixture of oxygen and nitrogen, 80% of the gas pressure is exerted by the nitrogen. if the total pressure is 2.0 atm, what pressure does the oxygen exert?
0.4 atm pressure exerted by oxygen if 80% of the gas pressure is exerted by the nitrogen.
What is pressure?Pressure is defined to be the amount of force exerted per area
80% of pressure is exerted by nitrogen gas.
So, 20% of pressure will be exerted by oxygen gas.
20% of 2.0 atm = 0.4 atm
Hence, 0.4 atm pressure exerted by oxygen if 80% of the gas pressure is exerted by the nitrogen.
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283.5 g of tin was heated from 25.6 to 107.5°C. How much energy was used to heat tin? (Specific heat capacity of Sn is 0.222 J/g x °C)
Answer: 5150 J
Explanation:
[tex]Q=mc \Delta T\\\\Q=(283.5)(0.222)(107.5-25.6)\\\\Q \approx \boxed{5150 \text{ J}}[/tex]
What is the percent yield if the quantity of reactants is sufficient to produce 0.86g of
NaCl but only 0.71g is obtained?
Taking into account definition of percent yield, the percent yield for the reaction is 82.56%.
Definition of percent yield
The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.
The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:
[tex]percent yield= \frac{actual yield}{theorical yield}x100[/tex]
where the theoretical yield is the amount of product acquired through the complete conversion of all reagents in the final product, that is, it is the maximum amount of product that could be formed from the given amounts of reagents.
Percent yield for the reaction in this case
In this case, you know:
actual yield= 0.71 gramstheorical yield= 0.86 gramsReplacing in the definition of percent yields:
[tex]percent yield= \frac{0.71 g}{0.86 g}x100[/tex]
Solving:
percent yield= 82.56%
Finally, the percent yield for the reaction is 82.56%.
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Hereditary information is stored inside the
Answer:Hereditary information is contained in genes, located in the chromosomes of each cell. Each gene carries a single unit of information. An inherited trait of an individual can be determined by one or many genes, and a single gene can influence more than one trait.
Explanation:
Can someone help??. This is super hard
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Current passes through a solution of sodium chloride. In 1. 00 second, 2. 68×1016na ions arrive at the negative electrode and 3. 92×1016cl− ions arrive at the positive electrode
The answer is the current passing between the electrodes is 10.56 mA., the direction of current is towards the negative electrode.
What is Electric Charge ?Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.
Electric charge can be positive or negative (commonly carried by protons and electrons respectively).
Like charges repel each other and unlike charges attract each other
Given that,
Number of sodium ions at the negative electrode, Na⁺ = 2.68 *10¹⁶
Number of chloride ions at the positive electrode,Cl⁻ = 3.92 *10¹⁶
(a) The current flowing in the circuit is due to the positive as well as negative charges such that total charge becomes:
Q= n e
Q = (Na⁺ +Cl⁻) e
Q= (2.68 *10¹⁶ +3.92 *10¹⁶) (1.6*10-19)
Q = 0.01056 C
The current is given by :
I=Q/t = 0.01056 /1 = 10.56mA
So, the current passing between the electrodes is 10.56 mA.
b) Since, positive ions are moving towards the negative electrode.
And, current is the flow of ions or electrons therefore, the direction of current is towards the negative electrode.
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The current is given by :
So, the current passing between the electrodes is 10.56 mA.
(b) The direction of electric current is towards negative electrodes.
If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been two half-lives? show your work
The rock will be 200 years old if there have been two half-lives.
What is the half life ?The half-life of a radioactive isotope refers to its decay period, which is the average lifetime of an atom before it disintegrates.
In this question (t½) of rock is 100 years, which means that after 100 years half of the sample would have decayed and half would be left as it is.
after two half lives or 200 years , the rock will be 200 years old.
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Question 2
1 p
White phosphorus ignites easily. This is an example of _____ property
- physical
- neither
- chemical
- both
Answer:
Chemical properties because if it was physical property then it will glow in dark
Solve the combined gas law problem
P₁ = 1.5 atm
V₁ = 3.0 L
T₁=20.0 °C
P2 = 2.5 atm
V₂ = ? L
T2 = 30.0 °C
Combined gas equation: P1V1/T1 = P2V2/T2
Solving for V2:
V2 = P1V1T2/P2T1
T1 = 20 °C = 293.15 K
T2 = 30 °C = 303.15 K
V2 = (1.5 × 3.0 × 303.15)/(2.5 × 293.15)
V2 = 1.86 L
Based on table n, uranium-238 and uranium-235 have different
a)decay modes
b)half lives
c)number of protons
d)number of electrons
According to table N, the isotopes uranium-238 and uranium-235 have different half lives.
What are radioactive nuclides?Radioactive nuclides are those nuclides that are able to undergo radioactive decay. They have specific modes of decay that is peculiar to each isotope.
Hence, according to table N, the isotopes uranium-238 and uranium-235 have different half lives.
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Is Hibiscus tea good for ACNE?
Answer:
Y E S
Explanation:
Hibiscus tea has plenty of skin care qualities, from helping your natural levels of collagen and elastin to reducing breakouts to balancing oil production. Hibiscus is known for its rich level of antioxidants, including vitamin C and beta-carotene.
I hope this helps ✍(◔◡◔)
What is the molar mass of unknown gas has a mass of 153 g and occupies 15 L at a temperature of 300 K and a pressure of 2 atm.
135 g/mol
17 g/mol
125 g/mol
160 g/mol
125 g/mol is the molar mass of unknown gas. Hence, option C is correct.
What is an ideal gas equation?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
First, calculate the moles of the gas using the gas law,
PV=nRT, where n is the moles and R is the gas constant. Then divide the given mass by the number of moles to get molar mass.
Given data:
P= 2 atm
V= 15 L
n=?
R= [tex]0.082057338 \;L \;atm \;K^{-1}mol^{-1}[/tex]
T=300 K
Putting value in the given equation:
[tex]\frac{PV}{RT}[/tex]=n
n= [tex]\frac{2 \;atm\; X \;15 \;L}{0.082057338 \;L \;atm \;K^{-1}mol^{-1} X 300}[/tex]
Moles = 1.21866 moles
Now,
Moles =[tex]\frac{mass}{molar \;mass}[/tex]
1.21866 =[tex]\frac{153 g}{molar \;mass}[/tex]
Molar mass= 125.54 mole/gram
125 g/mol is the molar mass of unknown gas. Hence, option C is correct.
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What can you determine about the feasibility of a reaction if the enthalpy is positive and
the entropy is positive?
A. The Gibbs energy will always be positive, and the reaction will never be feasible.
B. The Gibbs energy will always be negative, and the reaction will always be feasible.
OC. The reaction could be feasible above a certain temperature.
D. The reaction will usually occur because it is unlikely the entropy will be greater than the enthalpy.
Reset Selection
If the enthalpy is positive and the entropy is positive, the Gibbs energy will always be positive, and the reaction will never be feasible.
What is the Gibbs Free Energy?The Gibb Free Energy is used to obtain the feasibility of a reaction. If the Gibbs free energy is positive the reaction is not spontaneous. If the value is negative, the reaction is spontaneous while a zero values indicates equilibrium.
From the equation;
ΔG = ΔH - TΔS, it follows that if the enthalpy is positive and the entropy is positive, the Gibbs energy will always be positive, and the reaction will never be feasible.
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How many moles of Unknown weak acid (HA) in a 100L solution are required to produce a solution with PH =2 ? Ka of the Unknown weak acid (HA)=5x10⁻³
a. 3x10⁻³
b. 0.3x10⁻³
c. 3
d. 0.3
The moles of unknown weak acid (HA) in a 100L solution are required to produce a solution with pH 2 is 0.002 moles.
What is the equation of the acid dissociation constant, Ka?The acid dissociation constant of an acid is given by the formula below:
[tex]K_a= \frac{[A^{-}][H_3O^{-}]}{[HA]}[/tex]
Where
Ka = 5x10⁻³ pH = 2[H3O+] = 10^-2Volume of solution = 100 mL or 0.1 LSince, the Ka is given at equilibrium concentrations, [H3O+] = [A-]
[A-] = 10^-2
Making [HA] subject of the formula:
[tex][HA]= \frac{[10^{-2}][10^{-2}]}{5 \times 10^{ - 3} } = 0.02[/tex]
Moles of acid = 0.1 × 0.02 = 0.002 moles
Therefore, the moles of unknown weak acid (HA) in a 100L solution are required to produce a solution with pH 2 is 0.002 moles.
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What is a chemical property? Give an example.
Answer:
A chemical property example is fire.
Explanation:
Hope this helps!
Submit the answers to the checkpoint questions in the text box with the Lesson Review.
Part A Checkpoint
Directions: Complete each of the following questions.
(PICTURE FOR THE FIRST QUESTION)
1. Indicate the kind of energy represented in each example below:
a. Burning fuel in a car
b. Exploding an atomic bomb
c. Current moving in a wire
d. Tires sliding on pavement when brakes are applied
e. Football player running for a touchdown
2. All forms of energy except nuclear fission come from the _________.
3. Energy is ______________.
Energy is the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other forms.
The detonation of an atomic bomb releases enormous amounts of thermal energy, or heat, achieving temperatures of several million degrees in the exploding bomb itself. This thermal energy creates a large fireball, the heat of which can ignite ground fires that can incinerate an entire small city.
When the circuit is complete, there is a flow of charge (electric current). The electrons moving through the wire transfer energy to the wire in the form of heat. The particles in the wire, therefore, have more kinetic energy and so the temperature increases.
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Answer:ss
Explanation:ss
Which of these factors should remain constant in a simulation of natural
selection?
OA. The ratio of females to males
OB. The individuals observed
OC. The number of generations studied
OD. The population observed
SUBMIT
list three properties of water that are related to hydrogen bonding
What is the name of cuo? explain how you determined the bond type and the steps you used to determine the naming convention for the compound.
The name of CuO is Copper(II) oxide have the two most common oxidation states of copper are +2 and +1.
What is copper oxide used for?Copper oxide is a trace element for the zootechnical and agricultural sector. Cupric oxide is also used as a raw material for the production of catalysts and pigments in the field of ceramics, glass and plastics.
This compound makes two different types of bonds being the hydrogen bond when it's a hydrogen and covalent bond when we have an oxygen or a nitrogen.
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Are these structure form a week bases?
Answer:
Explanation:
I have only answered the blue boxed parts:
Amines are weak bases because they can accept protons from other things.
Sugars is neither acidic nor basic (cuz its not ionic)
Carboxylic acid are weak acids (not bases) cuz they donate protons to other things.
What is the change in the freezing point of water when 35.0 g of sucrose is
dissolved in 300.0 g of water?
Kf of water = -1.86°C/mol
molar mass sucrose = 342.30 g/mol
ivalue of sugar = 1
A. -0.183°C
B. 0.0606 °C
C. 0.217°C
D. -0.634°C
From the calculations, we can see that, the change in the freezing point is -0.634°C.
What is freezing point?The term freezing point refers to the temperature at which a liquid is changed to solid.
Given that;
ΔT = K m i
Number of moles sucrose = 35.0 g/ 342.30 g/mol = 0.1 moles
molality = 0.1 moles/ 300.0 * 10^-3 Kg
= 0.33 m
Thus;
ΔT = -1.86°C/mol * 0.33 m * 1
= -0.634°C
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Use the following equation to answer the following question
3 H2 + Na2 —-> 2 NH3
a) Determine the limiting reactant when 5.78 g of H2, and 6.28 g N2 are reacted to make NH3 you expect to get out of the chemical reaction.
Answer: nitrogen
Explanation:
Converting 5.78 g of hydrogen to moles, we know that the formula mass of hydrogen is about 2(1.00794)=2.01588 g/mol, so 5.78 grams is about 5.78/2.01588=2.867 mol.Converting 6.28 g of nitrogen to moles, we know that the formula mass of nitrogen is about 2(14.0067)=28.0134 g/mol, so 6.28 grams is about 6.28/28.0134 = 0.22417 mol.From the equation, we know that for every 3 moles of hydrogen consumed, 1 mole of nitrogen is consumed.
Considering the hydrogen, the reaction can occur 2.867/3=0.955 times.Considering the nitrogen, the reaction can occur 0.22417 times.Therefore, nitrogen is the limiting reactant.
Fatty acids can be ____________ , meaning they contain double bonds, or they can be ____________ , meaning they contain no double bonds
Match the phase to the correct definition.
1.
Anaphase
2.
Prophase
3.
Metaphase
4.
Telophase
a.
Chromosomes line up at the center of the cell.
b.
The DNA is organized into connected rods called chromosomes.
c.
New cells begin to form.
d.
The chromosomes are separated and move to opposite sides of the cell.
Answer:
1.) Anaphase ------> D.) The chromosomes are separated and move to opposite sides of the cell.
2.) Prophase -------> B.) The DNA is organized into connected rods called chromosomes.
3.) Metaphase -------> A.) Chromosomes line up at the center of the cell.
4.) Telophase ------> C.) New cells begin to form.
Select all the correct answers.
A red-hot iron nail is immersed in a large bucket of water. Although the nail cools down sufficiently to be held bare-handed, the temperature of the water barely increases. Which properties keep the water temperature from changing much?
The properties which keep the water temperature from changing much are;
water's high specific heat capacitythe large mass of waterWhat is specific heat capacity?The specific heat capacity is the property of a substance that shows how much its temperature changes when it is exposed to heat.
Thus, the properties which keep the water temperature from changing much are;
water's high specific heat capacitythe large mass of waterMissing parts:
A red-hot iron nail is immersed in a large bucket of water. Although the nail cools down sufficiently to be held bare-handed, the temperature of the water barely increases. Which properties keep the water temperature from changing much?
A.) water's high heat conductivity
B.) water's high specific heat capacity
C.) the iron nail's high heat conductivity
D.) the large mass of water
E.) the iron nail's high specific heat capacity
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Answer: waters high specific heat capacity the large mass of water
Explanation:
i got it right
Calculate the pKa of lactic acid (CH3CH(OH)COOH) given the following information. 3.005 grams of potassium lactate are added to 100. mL of a 0.500 M lactic acid solution producing a pH of 3.526.
Answer:
[tex]\displaystyle \text{p} K_a \approx 3.856[/tex]
Explanation:
Because 3.005 grams of potassium lactate is added to 100. mL of solution, its concentration is:
[tex]\displaystyle \begin{aligned} \left[ \text{KC$_3$H_$_5$O$_3$}\right] & = \frac{3.005\text{ g KC$_3$H_$_5$O$_3$}}{100.\text{ mL}} \cdot \frac{1\text{ mol KC$_3$H_$_5$O$_3$}}{128.17 \text{ g KC$_3$H_$_5$O$_3$}} \cdot \frac{1000\text{ mL}}{1\text{ L}} \\ \\ &= 0.234\text{ M}\end{aligned}[/tex]
By solubility rules, potassium is completely soluble, so the compound will dissociate completely into potassium and lactate ions. Therefore, [KC₃H₅O₃] = [C₃H₅O₃⁺]. Note that lactate is the conjugate base of lactic acid.
Recall the Henderson-Hasselbalch equation:
[tex]\displaystyle \begin{aligned}\text{pH} = \text{p}K_a + \log \frac{\left[\text{Base}\right]}{\left[\text{Acid}\right]} \end{aligned}[/tex]
[Base] = 0.234 M and [Acid] = 0.500 M. We are given that the resulting pH is 3.526. Substitute and solve for pKₐ:
[tex]\displaystyle \begin{aligned} (3.526) & = \text{p}K_a + \log \frac{(0.234)}{(0.500)} \\ \\ 3.526 & = \text{p}K_a + (-0.330) \\ \\ \text{p}K_a & = 3.856\end{aligned}[/tex]
In conclusion, the pKₐ value of lactic acid is about 3.856.
Calculate the molarity of a Ba(OH)2 solution if 1950 mL is completely titrated by 26.1 mL of 0.505 M HNO3
Answer: 0.01 M
Explanation:
[tex]M_{A}V_{A}=M_{B}V_{B}\\(26.1)(0.505)=(1950)M_{B}\\M_{B}=\frac{(26.1)(0.505)}{1950} \approx \boxed{0.01 \text{ M}}[/tex]
Compare and contrast nuetrons,protons, and electrons
Match the following terms:
Answer:
See below ~
Explanation:
A to B
⇒ Solid Phase
==========================================================
B to C
⇒ Melting
==========================================================
C to D
⇒ Liquid Phase
==========================================================
D to E
⇒ Vaporizing
============================================================
E to F and beyond
⇒ Gas Phase