Answer:
1224.7
Explanation:
Each lb is 453.59
Based on the conversion factor, a person loses 2.70 lb in two weeks loses 1225.8 g
How can we concer from pounds, lb to grams?The conversion factor from pounds to grams is given as follows:
1 pound = 454 gTherefore, 2.70 pounds can be converted to grams as follows:
270 lb = 2.70 × 454 g/ 1 lb
270 lb = 1225.8
Thus, a person loses 2.70 lb in two weeks loses 1225.8 g
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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%.
PLEASE HELP WITH PAGE 1 FOR QUESTIONS 1, 2, 3 WITH THE GRAPHING THANK YOU.
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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Question: In experiment your teacher has provided you with a sample of sandy, salty, ocean water and
asked you to separate the components of the mixture. In no more than four sentences, state if the
sample is a homogeneous or heterogeneous mixture, with supporting evidence, and describe how you
would accomplish the task.
Answer:
Explanation:
Homogeneous mixture is a mixture in which the components of the mixture are in the same proportion throughout any sample extracted from the mixture while an heterogeneous mixture is a mixture in which the components of the mixture differ in term of proportion when different samples of the mixture are extracted and compared.
For example, a sandy water will have some parts (usually the bottom) of the mixture with more sand than other parts of the mixture, hence, it (sandy water) is a heterogeneous mixture. While salty and ocean water has it's salt dissolved in the same proportion throughout the water in the mixture, hence salty and/or ocean water is a homogeneous mixture.
Sandy water can be separated by filtration (i.e using a filter paper to separate the sand from the water when the mixture is poured over a filter paper) while salty and ocean water can be separated by distillation (i.e boiling of the mixture so the water molecules can boil and move through a tube as gas or steam into another container where they are cooled and converted back to liquid or water while leaving the solid salt component of the mixture in the boiling tube).
Which of the following would a chemist be most likely to study? A. what happens when a moving car comes to a stop B. what happens when iron rusts in the presence of water C. what happens when ice melts to form liquid water D. what happens when light reflects from a shiny surface
Answer:
B. what happens when iron rusts in the presence of water
Explanation:
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 .
Does pineapple belong in pizza
Answer:
No no no and no no no no no no
Answer:
This is quite a controversial question ahaha. Personally, I think pineapple on pizza is good sometimes. depends on the day though.
Explanation:
To me it is a good combination of sweet and salty. The pineapple is also pretty refreshing.
You 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!
what is the first step to solving a problem ?
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
Normal human body temperature is 98.6 °F. This is equivalent to °C or K is :___________.
Answer:
74ifhdyteuyteutyruf
5.
Which statement is false?
Chemistry explains many aspects of nature.
Knowledge of chemistry allows the public to make informed decisions.
A beaker cannot be used for measuring the volume of a liquid because _____.
Answer:
Data obtained can't be accurate.
Explanation:
A beaker can't be used for measuring the volume of a liquid because they did not calculate volume of a liquid accurately and precisely. The marks present on the beaker are not accurate, it is just an estimate so by measuring the volume of any liquid using beaker give us a false data so that's why beaker are not used for the measurement of a volume.
Pre-lab Assignment
1. Student A measures an object and records a value of 1.5 cm. Student B measures the same object
and records a value of 1.50 cm. They have both done their measurements correctly. Why do these
measurements differ?
a. They aren't different.
b. Person A used a ruler with markings every 0.1 cm. Person B used a ruler with markings every
0.01 cm.
c. Person A used a ruler with markings every 1 cm. Person B used a ruler with markings every 0.1
cm.
d. Person A rounded their measurement.
2. When multiplying or dividing measured numbers, we use the measurement with the least number of
significant figures to determine the number of significant figures (sf) in our answer. For example:
3.5 cm x 4.75 cm - 17 cm? (even though the calculator gives 16.675) Solve the following problems
assuming all are measured numbers. Report the correct number of significant figures.
a. 7.00 x 15.00 =
b. 40.2.1.901 =
c. (0.003)(13.2) =
d. 1.590+ 0.3975 =
Answer:
1. d. Person A rounded their measurement
2) a. 105.
b. 76.4
c. 0.04
d. 1.988
Explanation:
1. Measuring an object is done with the least precise one. Person A recorded 1.5cm while Person B recorded 1.50cm of the same object. This measurement differs in the sense that Person A rounded up their measurement to 2 significant figures (1.5) while Person B recorded their answer as three significant figures (1.50).
2. During multiplication and division, the result is written as the measurement in the lowest significant figure.
a. 7.00 x 15.00 = 105. Calculator showed 105.00, which is 5 s.f (two zeros after decimal point are significant). The least significant figure is 3, hence 105.00 is rounded up to 105.
b. 40.2.1.901 = 76.4; The calculator answer of this operation is 76.420200 but since the lowest significant figure is 3. We round up our answer to 3 s.f i.e. 76.4
c. (0.003)(13.2) = 0.04. For this operation, calculator answer is 0.0396, however, the lowest significant figure in the question is 1 i.e. 0.003. Note that the two zeros before 3 are insignificant. Hence, our answer will be rounded up to 1 s.f i.e. 0.04
d. 1.590+ 0.3975 = 1.988. the calculator answer to this operation is 1.9875. However, the least significant figure in the question is 4 i.e. 1.590. hence, the answer will be rounded up to 4 s.f which is 1.988.
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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what is the mass of an electron is
Answer:
the rest mass of an electron is 9.1093837915
Answer:
Fundamental properties. The invariant mass of an electron is approximately 9.109×10−31 kilograms, or 5.489×10−4 atomic mass units. On the basis of Einstein's principle of mass–energy equivalence, this mass corresponds to a rest energy of 0.511
How many protons and neutrons does iron-56 have? Question 10 options: 26 protons and 56 neutrons 26 protons and 26 neutrons 30 protons and 56 neutrons 26 protons and 30 neutrons
Answer:
Protons: 26
Neutrons: 30
Explanation:
Measured value 28.7053 cm, which has six significant figures. Round the measurement to five significant figures
Answer:
28.705 cm
Explanation:
Hello,
In this case, for rounding the number to five significant figures we must "cut" it at 5 so we hide the 3, therefore it turns out:
28.705 cm.
Moreover, we must realize that since such 3 is less than five, we do not modify the previous five to six, case which would happen if that three has changed to five or more.
Regards.
The TV weather forecaster announces that one location has a 30% chance of rain tomorrow and a 35% chance of hail. What is the probability that it will rain or hail in this location?
Answer: 65%
Explanation:
When in probability and the outcome is mutually exclusive which means that either one or the other will happen then the probabilities of the events should be added up.
P(A or B) = P(A) + P(B)
P(Rain or Hail) = P(Rain) + P(Hail)
P(Rain or Hail) = 30% + 35%
P(Rain or Hail) = 65%
What has the smallest mass,proton neutron or electron ?
Explanation:
Hey there!!
The answer is Electrons.
Electrons are the small part of an atom that revolves around the nucleus of an atom.
Hope it 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 = 87.8kJ270kJ 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:
Water drops that fall on a smooth surface tend to form rounded drops or beads. Then, if you touch a piece of paper to the drop, water appears to move up into the paper on its own. Identify and describe the properties of water that explain this phenomenon.
Answer:
Surface tension
Capillary action
Explanation:
Surface tension is the force acting along the surface of the liquid causing the liquid surface to behave like a stretched elastic skin. Surface tension causes the water drops that fall on a smooth surface to form rounded drops or beads.
If you touch a piece of paper to the drop, water appears to move up into the paper on its own due to capillarity. Capillarity is the tendency of a liquid to rise or fall in a narrow tube.
A protein has an isoelectric point (pI) of 9. Which of the following statements best describes the state of this protein in aqueous solution at pH 7?
A. The side chains of the protein's basic residues will be mostly uncharged
B. The side chains of the protein's acidic residues will be mostly protonated
C. The protein will have no net charge
D. The protein will have a net positive charge
E. The protein will have a net negative charge
Answer:
The correct option is D
Explanation:
From the question we are told that
The pH of the aqueous solution is [tex]pH = 7[/tex]
The isoelectric point is [tex]pl = 9[/tex]
From the data given we see that the
[tex]pH[/tex] is below [tex]pl[/tex]
So the protein will have a net positive charge
A protein has an isoelectric point (pI) of 9, the statement which best describes the state of this protein is that the protein will have a net positive charge.
What is isoelectric point?Isoelectric point of any susbatnce is the pH of the substance where net charge on that substance will be zero, i.e. no. of positive charged ions will equal to the number of negative charged ions.
In the question it is given that value of isoelectric point (pl) of protein is 9 and given value of pH is 7. It means that isoelectric point is higher that given pH so the protein molecule should bear a positive charge on it. If pH value is greater than pl value then molecule will bear a negative charge.
Hence option (D) is correct.
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Chocolate candy melting in your hand is what type of heat transfer
Why is important to only change one variable in a controlled experiment
A variable within a scientific experiment is something that is changed (i.e. it varies). There should be only one manipulated variable within a scientific experiment so that the experimenter can be certain it is this variable which causes a pattern in the resultant data, if any exists at all.
HOPE IT HELPS PLZ BRAINLIEST
1. Why is it important to know the names and appearance of lab equipment before doing laboratory work? 1. So you will score higher on the lab test. 2. So you quickly obtain your laboratory supplies before lab. 3. So you can follow the lab instructions clearly. 4. So you can make sure everything has been cleaned before beginning the lab procedure.
Answer:
1. because what if you do a incorrect ion? it would be all wrong! 2. you dont get it quickly because! you might get the wrong equipment. 4. yep! no food or drinks!
Explanation:
hope this helps ☻︎
5. Three solution A, B and C have pH 2, 8 and 7 respectively.
A. Which one of these will turn blue litmus paper into red.
B. Which one of these will turn china rose indicator into green
C. Which one of these will not change colour of any indicator
Answer:
A. The solution with a pH of 2 will turn the litmus paper red
B. The solution with a pH of 8 will turn the China rose indicator green
C. The solution with a Ph of 7 will not change the color of the blue litmus indicator or of the China rose indicator
Explanation:
Blue litmus paper will only change color if it is dipped into an acidic mixture which turns it red. It will not change color at all in a basic or neutral Ph solution.
China rose turns dark pink in an acidic solution and green in a basic solution. However it has no change in color with a neutral solution.
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
Calculate the PE of an object that has a mass of 2kg that is resting on a 6m table. HELP ME PLEASE I REALLY NEEEEED HELP!!!! 21 POINTS PLEASSEEEE
Answer:
Calculate the unknown variable in the equation for gravitational potential energy, where potential energy is equal to mass multiplied by gravity and height; PE = mgh. Calculate for different gravity of different enviornments - Earth, the Moon, Jupiter, or specify your own. Free online physics calculators, mechanics, energy, calculators.
Explanation: