When you calculate apercent recovery you may find sometimes that it islarger than 100%. Assuming this is NOT due to errors associated with zeroing the balance, subtracting the weight of the watch glass or weigh paper, or inaccuracies in the balance calibration, suggest a possible reason for this.
Answer:
Presence of impurities in the product.
Explanation:
Laboratory experience has shown that the percent yield obtained from a reaction may be greater than 100% if the product obtained from the reaction contains impurities that causes its mass to be greater than it actually would be if the product was pure.
A typical impurity that may be present in a product is the solvent used. This can be removed by evaporation of the solvent or by washing the product thoroughly.
Reaction of solid products with gases may also increase the percentage yield above 100%.
A football field is supposed to be exactly 120yd long, including the end zones. How many inches is this?
Answer:
4320 inches
Explanation:
math
A football field is supposed to be exactly 120yd long, including the end zones is 4320 inches.
What are zones?Zones are defined as a space that is physically or artificially isolated from other spaces. There are numerous sorts and sizes of zones.
Zones are also defined as a region that is designated as having a specific average annual minimum temperature, which is important for many plants to survive.
There are four types of zones.
The intimate spaceThe personal spaceThe social spaceThe personal spaceThe Torrid Zone, Temperate Zone, and Frigid Zone are the three temperature-based regions of the Earth.
Planting zones are predetermined areas based on the types of plants that thrive there.
Thus, a football field is supposed to be exactly 120yd long, including the end zones is 4320 inches.
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HELP FAST!!!
As a roller coaster car travels down a hill, which type of change in energy allows
it to speed up?
a) potential energy changing into heat energy
b) potential energy changing into kinetic energy
c) kinetic energy changing into heat energy
d) kinetic energy changing into potential energy
Answer:
B
Explanation:
Calculate the mass of sucrose necessary to make a 5% by mass sucrose solution if the solution contains 50.0 ml of distilled water. (Hint: the total mass of the solution is the mass of sucrose plus the mass of water.)
Answer:
2.6 g
Explanation:
Percent concentration = 5%
Volume of water = 50ml
Since 1ml of water = 1g of water
Mass of water= 50g
Let the mass of sucrose be x
Mass% = mass of solute/mass of solute + mass of solvent × 100
5= x/x+ 50 ×100
5/100 = x/x + 50
0.05 = x/x + 50
0.05(x + 50) = x
0.05x + 2.5 = x
2.5 = x - 0.05x
2.5 = 0.95x
x= 2.5/0.95
x=2.6 g
Ignore my writing, but I’m so confused on this. Please help me
Before this it was talking about sig figs, so I’m not sure if you’re supposed to use sig figs in this or not.
Explanation:
You are suppose to use sig figs.
How far will you travel in 180 seconds running at a rate of 6 m/s?
Answer:
1080 meters.
Explanation:
Calculate the mass of forsterite that contains a million oxygen atoms. Be sure your answer has a unit symbol if necessary, and round it to significant digits.
Answer:
2.33×10¯¹⁶ g of forsterite
Explanation:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ atoms. This equally means that 1 mole of forsterite (Mg2SiO4) contains 6.02×10²³ atoms.
1 mole of forsterite (Mg2SiO4) = (24×2) + 28 + (16×4)
= 48 + 28 + 64
= 140 g
Finally, we shall determine the mass of forsterite that contains a million oxygen atoms.
140 g of forsterite (Mg2SiO4) contains 6.02×10²³ atoms.
Therefore, Xg of forsterite (Mg2SiO4) will contain 1×10⁶ atoms of oxygen i.e
Xg of forsterite (Mg2SiO4) =
(140 × 1×10⁶) /6.02×10²³
= 2.33×10¯¹⁶ g
Therefore, 2.33×10¯¹⁶ g of forsterite contains a million oxygen atoms..
The mass of forsterite that contains a million oxygen atoms is 5.67 × 10^-17 g.
The chemical formula of forsterite is Mg2SiO4. Now, molar mass of forsterite is; 2(24) + 28 + 4(16) = 140 g/mol
Next, we have to obtain the number of oxygen atoms that are found in 1 mole of forsterite as follows;
Number of oxygen atoms in 1 mole = 1 × 4 × 6.02 × 10^23 = 24.08 × 10^23 atoms
Now;
If 1 mole of forsterite contains 24.08 × 10^23 atoms oxygen atoms
x moles of forsterite contains 1 × `10^6 atoms
x = 1 mole × 1 × `10^6 atoms/24.08 × 10^23 atoms
x = 4 × 10^-19 moles
Mass of forsterite that contains a million oxygen atoms = 4 × 10^-19 moles
× 140 g/mol = 5.67 × 10^-17 g
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What is the correct answer with the appropriate significant digits?6.25 x 19.50
why diamond has a high melting point
Explanation:
Each carbon atom is covalently bonded to four other carbon atoms in diamond. A lot of energy is needed to separate the atoms. This is because covalent bonds are strong. This is the reason why diamond has a high melting point.
Consider the interaction of two hydrogen ls atomic orbitals of the same phase. Which statements below is an incorrest description of this interaction? A) A sigma bonding molecular orbital is formed. B) The molecular orbital formed is lower in energy than a hydrogen 1s atomic orbital. C) The molecular orbital formed has a node between the atoms. D) The molecular orbital formed is cylindrically symmetric. E) A maximum of two electrons may occupy the molecular orbital formed.
Answer:
B) The molecular orbital formed is lower in energy than a hydrogen 1s atomic orbital.
Explanation:
When two atoms of hydrogen come close to each other , there is formation of molecular orbital . Due to overlap of 1 s orbital of one and 1 s orbital of another atom , two molecular orbitals are formed . One of these molecular orbital has energy less than 1 s atomic orbital . It is called 1 s sigma bonding molecular orbital . The other molecular orbital has energy more than 1 s atomic orbital . It is called antibonding molecular orbital . Two electrons occupy bonding sigma molecular orbital .
So , the statement that "the molecular orbital formed is lower in energy than a hydrogen 1s atomic orbital " is wrong .
A runner competed in a 5-mile run. How many yards did she run?
a-8800 yards
b-8800 miles
с-8657 yards
270kJ are needed to keep a 75 watt light bulb burning for 1 hour. How many kilocalories are needed to burn this light bulb for 3 hours?
Answer:
For 1 hour 75w light bulb requires 270 kj for burning
for 3 hours 75 w light bulb requires 270*3 = 810kj for burning
Explanation:
Which is a symbol that represents SI units for temperature.
A. 'C
B. g
C. L
D. 'F
Answer:
A.'C
Explanation:
Please answer my question
Answer:
the answer would be a
Explanation:
Jade wants to measure the thickness of a copper wire. She wound the copper wire 30 times around a pencil and used a ruler to measure the length of the wound wire as shown in the figure.
Section of ruler is shown next to a pencil with a wire wound around it. The markings on the ruler are from zero to two centimeters. There are two small markings, one is between zero and one and the other is between one and two. The length of the entire wound wire starts at zero and goes to the small marking which is exactly between one and two.
Which of these is the most accurate thickness of the copper wire? (1 point)
0.001 cm
0.005 cm
0.01 cm
0.05 cm
Answer: 0.05
Explanation:Divide the length (1.5 cm) by the number of turns (30)
The direct proportion rule allows you to find that the correct answer for the result of the thickness of the copper wire is:
0.05 cm
Copper is a strong material with which the cross section is constant, therefore the copper wire has a constant thickness, which is why when making a full turn it advances the same amount
When Jade wound thirty times (n = 30) it has the same diameter each time, therefore with a direct rule of proportions we can find the thickness of the wire.
If in 30 laps we have 1.5 cm, in one lap we have?
[tex]x= 1 turn ( \frac{1.5 cm}{30 turn} )[/tex]
x = 0.05 cm
In conclusion using a direct rule of proportions we can that the correct answer for the result of the thickness of the copper wire is:
0.05 cm
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In order to find the density of an object, Maria is trying to measure its volume. However, the object does not fit in the
tool she is using. To solve this problem, Maria decides to break apart the object.
Will Maria be able to find density following this method? Why or why not?
O Yes, if she measures the volume and mass of all the pieces of the object, she should be able to calculate density
O Yes, if she measures the volume and mass of one of the pieces of the object, she should be able to calculate
density.
O No, once the object is broken apart and the shape has been altered, it is not possible to calculate the volume of
the whole object to find density.
O No, once the object is broken apart and the shape has been altered, it is not possible to calculate the mass of the
object to find density.
Answer: She needs to divide the mass by the volume to find the density of the object.
Explanation:
5.
Which statement is false?
Chemistry explains many aspects of nature.
Knowledge of chemistry allows the public to make informed decisions.
A 5.0g sample of MgCl2 may contain measurable amounts of other compounds as impurities. Which of the following quantities is (are) needed to determine that the sample is pure MgCl2 ?
Answer:
The mass of Mg and the mass of Cl in the sample
Explanation:
We have that the sample's is purity is simply the mass of Mg and the mass of Cl in the sample
From the Question we are told that
Mass of MgCl2 =5g
Therefore
What we need to determine that the sample's is purity is simply the mass of Mg and the mass of Cl in the sample because
the mass of MgCl should be equal to mass of Mg and mas of Cl
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Which of the following statements does not correctly characterize the rate of evaporation of a liquid?
I. Increases with increasing temperature because molecules have higher kinetic energies.
II. Increases with increasing surface area of the liquid because more molecules are located at the 54. surface.
III. Increases with stronger intermolecular forces because molecules in the liquid repel each other more.
a. I only
b. IIl only II only
c. II and III only
d. I and II only
Answer:
d. I and II only
Explanation:
Evaporation is the breakaway of liquid molecules through the surface of a liquid, into the surrounding atmosphere in the form of a gas. Evaporation increases with temperature, since the molecules posses more kinetic energy to break through the liquid surface barrier at a higher temperature. Also, an increase in the surface area puts more of the molecules of the liquid close to the interface of the liquid and the surrounding atmosphere, increasing their chances of breaking away. An increase in the intermolecular forces between the molecules of the liquid will only decrease the rate of evaporation, since more energy will be required by the liquid molecules to break free from the bond between them and their neighboring molecules.
Which of the changes are chemical changes?
Ocean water becomes colder; the density of ocean water increases or decreases?
Answer:
the density increases
Explanation:
Coz high temperature makes water less dense. As water gets warmer, its molecules spread out, so it becomes less dense. As it gets colder, it becomes denser
What contributions led to the acceptance of the heliocentric model of the solar system
Answer:
It was just on a way and scienticts cant really "delete" it from galaxy so they descided accepting it and study it.
Explanation:
Answer:
In 1543 he further developed the heliocentric model. Copernicus was able to work out the arrangement of the known planets and how they move around the sun.
Explanation:
hope this helps:)
Calculate ΔHrxn for the following reaction:
5C(s)+6H2(g)→C5H12(l)5C(s)+6H2(g)→C5H12(l)
Use the following reactions and given ΔH values:
C5H12(l)+8O2(g)→ 5CO2(g)+6H2O(g) ΔH= -3505.8 kJ
C(s)+O2(g)→CO2(g) ΔH= -393.5 kJ
2H2(g)+O2(g)→ 2H2O(g) ΔH= -483.5 kJ
Answer:
ΔH = 87.8kJ
Explanation:
You can determine ΔH of a reaction from the sum of similar reactions (Hess's law). In the problem with the given ΔH:
1. C5H12(l)+8O2(g)→ 5CO2(g)+6H2O(g) ΔH= -3505.8 kJ
2. C(s)+O2(g)→CO2(g) ΔH= -393.5 kJ
3. 2H2(g)+O2(g)→ 2H2O(g) ΔH= -483.5 kJ
5 times 2. + 3 times 3:
5C(s) + 8O2(g) + 6H2(g) → 5CO2(g) + 6H2O(g)
ΔH= 5*(-393.5 kJ) + 3*(-483.5 kJ) = -3418kJ
Now, this reaction - 1:
5C(s)+6H2(g) → C5H12(l) ΔH= -3418kJ - (-3505.8kJ)
ΔH = 87.8kJYou may want to reference (Page) Section 12.4 while completing this problem. Enter the balanced chemical equation for the complete combustion of each of the following hydrocarbons found in gasoline used to start a fire:________.
Part A. liquid nonane
Express your answer as a chemical equation including phases.
Part B. liquid isopentane (2-methylbutane)
Express your answer as a chemical equation including phases.
Part C. liquid 3-ethyltoluene
Express your answer as a chemical equation including phases.
Answer:
See explanation
Explanation:
In this question, we have to remember that in all combustion reactions we will have Oxygen as reactive ([tex]O_2[/tex]) and the products are Carbon dioxide ([tex]CO_2[/tex]) and Water ([tex]H_2O[/tex]). Additionally, for the states, we will have (l) for the liquid state and (g) for the gas state. So, we can analyze each reaction:
Part A.
The formula for nonane is [tex]C_9H_2_0[/tex], with this in mind we can write the combustion reaction:
[tex]C_9H_2_0_(_I_)~ +~ O_2~->~CO_2_(_g_)~ +~H_2O_(_g_) [/tex]
When we balance the reaction we will obtain:
[tex]C_9H_2_0_(_I_)~ +~14 O_2_(_g_)~->~9CO_2_(_g_)~ +~10H_2O_(_g_) [/tex]
Part B.
The formula for 2-methylbutane is [tex]C_5H_1_2[/tex], with this in mind we can write the combustion reaction:
[tex]C5H12_(_I_)~ +~O_2_(_g_)~->~CO_2_(_g_)~ +~H2O_(_g_) [/tex]
When we balance the reaction we will obtain:
[tex]C5H12_(_I_)~ +~8O_2_(_g_)~->~5 CO_2_(_g_)~ +~6 H2O_(_g_) [/tex]
Part C.
The formula for 3-ethyltoluene is [tex]C_9H_1_2[/tex], with this in mind we can write the combustion reaction:
[tex]C_9H_1_2_(_I_)~+~O_2_(_g_)~->~CO_2_(_g_)~+~H2O_(_g_)[/tex]
When we balance the reaction we will obtain:
[tex]C9H12_(_I_)~ +~12O_2_(_g_)~->~9CO_2_(_g_)~ +~6H2O_(_g_)[/tex]
See figure 1 for further explanations.
I hope it helps!
Can a smoothie be separated by physical means ?
Answer:
No because the sugar that went to it dissolved and the fruits are very blended in. It depends what smoothie it is because you can evaporate a strawberry smoothie and have only the strawberry mix instead of the water or milk.
Explanation:
Is it true you will often have more control over the setting when photographing a pet versus a wild animal
Answer: Sí
Explanation: ya que una mascota es inofensiva, pero para fotografiar a un animal salvaje, debes esperar pacientemente el momento perfecto
Hydrogen reacts with nitrogen monoxide to form dinitrogen monoxide (laughing gas) according to the equation: H2O(g) + 2NO(g) rightarrow O + H2O(g)NO (M) 0.30 0.60 0.60H2 (M) 0.35 0.35 0.70Rate (M/L/s) 3.822 x 103 1.529 x 10-2 3.058 x 10-2 A) Determine the rate law according to the following data. B) Determine the rate constant (in mol-2. L2. s-1).C) Determine the orders with respect to each reactant.
Answer:
A. [tex]r=k[NO]^2[H_2][/tex]
B. [tex]k=0.121\frac{L^2}{mol^2*s}[/tex]
C. Second-order with respect to NO and first-order with respect to H₂
Explanation:
Hello,
In this case, for the reaction:
[tex]H_2O(g) + 2NO(g) \rightarrow N_2O + H_2O(g)[/tex]
The rate law is determined by writing the following hypothetical rate laws:
[tex]3.822x10^{-3}=k[0.3]^m[0.35]^n\\\\1.529x10^{-2}=k[0.6]^m[0.35]^n\\\\3.058x10^{-2}=k[0.6]^m[0.7]^n[/tex]
Whereas we can compute m as follows:
[tex]\frac{3.822x10^{-3}}{1.529x10^{-2}} =\frac{[0.3]^m[0.35]^n}{[0.6]^m[0.35]^n} \\\\0.25=(0.5)^m\\\\m=\frac{log(0.25)}{log(0.5)} \\\\m=2[/tex]
Therefore, the reaction is second-order with respect to NO. Thus, for hydrogen, we find n:
[tex]\frac{1.529x10^{-2}}{3.058x10^{-2}} =\frac{[0.6]^2[0.35]^n}{[0.6]^2[0.7]^n} \\\\0.5=(0.5)^n\\\\n=\frac{log(0.5)}{log(0.5)}\\ \\n=1[/tex]
A) Therefore, the reaction is first-order with respect to H₂. In such a way, we conclude that that the rate law is:
[tex]r=k[NO]^2[H_2][/tex]
B) Rate constant is computed from one kinetic data:
[tex]k=\frac{1.529x10^{-2}\frac{mol}{L*s} }{(0.6\frac{mol}{L} )^2(0.35\frac{mol}{L})}\\\\k=0.121\frac{L^2}{mol^2*s}[/tex]
C. As mentioned before, reaction is second-order with respect to NO and first-order with respect to H₂.
Best regards.
The order with respect to NO has been 2, while the order with respect to water has been 1.
The rate law has been the representation of the chemical concentration responsible for determining the rate of the reaction. The balanced chemical equation has been:
[tex]\rm H_2O\;+\;2\;NO\;\rightarrow\;N_2O\;+\;H_2O[/tex]
A. The rate equation for the reaction has been:
Rate = Rate constant [tex]\rm [H_2O]^m\;[NO]^n[/tex]
Where, m and n are the rate of the respective reactants.
The rate with respect to NO from the given data can be given as:
The ratio of Rate 1 to rate 2 with concentration of NO
[tex]\rm \dfrac{3.822\;\times\;10^-^3}{1.529\;\times\;10^-^2}[/tex] = [tex]\rm \dfrac{[0.3]^m\;[0.35]^n}{[0.6]^m\;[0.35]^n}[/tex]
m = 2
The rate of reaction with respect of NO has been 2.
The rate of reaction with water concentration has been:
[tex]\rm \dfrac{1.529\;\times\;10^-^2}{3.058\;\times\;10^-^2}[/tex] = [tex]\rm \dfrac{[0.6]^m\;[0.35]^n}{[0.6]^m\;[0.7]^n}[/tex]
n = 1
The rate of reaction with respect of water has been 1.
The rate law for reaction has been:
Rate = k [tex]\rm [H_2O]^1\;[NO]^2[/tex]
B. The rate constant can be given as:
Rate = 3.822 [tex]\rm \times\;10^-^3[/tex]
Concentration of NO = 0.6
Concentration of water = 0.35
The rate constant from the rate law can be given as:
3.822 [tex]\rm \times\;10^-^3[/tex] = k [tex]\rm [0.6]^2\;[0.35][/tex]
k = 0.121 [tex]\rm mol^-^2\;L^2\;s^-^1[/tex]
C. The order with respect to NO has been 2, while the order with respect to water has been 1.
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How does heat conduction work in the metal brownie pan?
The heat from the oven heats up the metal pan, and the metal pan transfers the heat to the brownies.
What is heat conduction?Heat conduction is defined as the transfer of heat in an object from the area of hotter region to the area of cooler region through microscopic particles and movement of electrons within the body.
All the objects such as metal brownie pan that is capable of conducting heat is called the term thermal conductivity.
Examples of metals that are good conductors of heat include the following Gold, Silver, Copper, Aluminium, Iron.
Therefore, is can be concluded that the oven heats up the metal pan, and the metal pan transfers the heat to the brownies.
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How do you determine the last digit in any measured number
Answer:
Explanation:
The last number in a measured number is always an estimated digit.
8. An example of an atom that has no charge is one that has
A. 2 protons, 2 electrons, and 1 neutron.
B. 3 protons, 2 electrons, and 1 neutron.
C. 1 proton, 2 electrons, and 3 neutrons.
D. 3 protons, 1 electron, and 3 neutrons.
Please help ASAP, thank you
Answer:
A. 2 protons, 2 electrons, and 1 neutron .
Answer:
A 2 protons, 2electrons,1 neutron
Use the observation in the first column
Observation Questions
At 4 °C, Substance E has a Which has a higher boiling point
vapor pressure of 86. torr and Substance A. Substance E
F has a vapor pressure of 136. torr. B. Substance F
C. Neither, E and F have the
same boiling point.
The enthalpy of vaporization of Substance At any temperature where both
C is smaller than that of Substance D. substances are liquid which has
has the higher vapor pressure?
A. Substance C
B. Substance D
C. Neither, C and D have the
same vapor pressure
Which has a higher vapor pressure?
At 1 atm pressure Substance A boils at A. Substance A
129. °C and Substance B B. Substance B
boils at 154. °C. C. Neither, A and B have the
same vapor pressure.
Answer:
A. Substance E
A. Substance C
A. Substance A
Explanation:
Given that:
At 4 °C, Substance E has a vapor pressure of 86. torr and Substance F has a vapor pressure of 136. torr
Which has a higher boiling point?
A. Substance E
B. Substance F
C. Neither,EandF have the same boiling point
The vapor pressure varies inversely proportional to the boiling point.
[tex]\mathbf{vapor \ pressure \ \ \alpha \ \ \dfrac{1}{boiling \ point}}[/tex]
Therefore, the lower the vapor pressure, the higher the boiling point.
At 4°C, Substance E with a lower vapor pressure of 86. torr will have a higher boiling point from the given information.
2.
Recall that :
[tex]\mathbf{vapor \ pressure \ \ \alpha \ \ \dfrac{1}{enthalpy \ of \ vaporization}}[/tex]
therefore, the lower the enthalpy of vaporization, the higher the vapor pressure at any given temperature.
Given that:
Substance C has an enthalpy of vaporization smaller than that of substance D. Then, substance C has a higher vapor pressure.
3.
We've earlier said that:
The vapor pressure varies inversely proportional to the boiling point.
[tex]\mathbf{vapor \ pressure \ \ \alpha \ \ \dfrac{1}{boiling \ point}}[/tex]
Therefore, the lower the vapor pressure, the higher the boiling point.
As such, Substance A will have a higher boiling point.