Explanation:
Above we have simply looked the condition that where we put decimal point that gives your needed answer after round off.
For example:
we have to make 2 s.f from 345 so we kept decimal after 3 and we rounded off to make 3.5 from 3.45
Hope you got it
_________ is the mechanical separation of a mixture based upon the sizes of the mixtures components.
Answer:
Sieving
Explanation:
Sieving is a mechanical separation technique which depends on the relative sizes of particles in the mixture.
A mesh is used to discriminate between particle sizes. Particles in the mixture which are larger than the mesh size do not pass through the sieve, hence particles whose size is less than that of the mesh are separated from the rest of the particles in the mixture.
The typical capacity for human lungs is approximately 5800 mL. At a temperature of 37C (average body tempurature) and pressure of 0.98 atm, how many moles of air do we carry inside our lungs?
Answer:
0.22 moles of air we carry inside our lungs.
Explanation:
An ideal gas is a theoretical gas that is considered to be composed of point particles that move randomly and do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.
The gas laws are a set of chemical and physical laws that allow determining the behavior of gases in a closed system. The parameters evaluated in these laws are pressure, volume, temperature and moles.
The ideal gas law is an equation that relates the variables pressure P, temperature T and volume V if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases as follows:
P * V = n * R * T
In this case:
P= 0.98 atmV= 5800 mL= 5.8 L (being 1,000 mL= 1 L)n= ?R= 0.082 [tex]\frac{atm*L}{mol*K}[/tex]T= 37 C= 310 K (being 0 C= 273 K)Replacing:
0.98 atm* 5.8 L= n* 0.082 [tex]\frac{atm*L}{mol*K}[/tex] * 310 K
Solving:
[tex]n=\frac{0.98 atm* 5.8 L}{0.082 \frac{atm*L}{mol*K} *310 K}[/tex]
n= 0.22 moles
0.22 moles of air we carry inside our lungs.
A jeweler has five rings, each weighing g, made of an alloy of silver and gold. She decides to melt down the rings and add enough silver to reduce the gold content to . How much silver should she add
Complete question :
A jeweler has five rings, each weighing 18 g, made of an alloy of 10% silver and 90% gold. She decides to melt down the rings and add enough silver to reduce the gold content to 75%. How much silver should she add?
Answer:
Kindly check explanation
Explanation:
Given the following :
Weight of each alloy = 18g
Initial % of Silver = 10% = 0.1
Initial % of Gold = 90% = 0.9
New % of gold = 75% = 0.75
Hence, new % of silver will be (1 - 0.75) = 0.25
Let the amount of silver to be added = s
Hence,
Initial gold content = final gold content + added silver
18 * 0.9 = 0.75(18 + s)
16.2 = 13.5 + 0.75s
16. 2 = 13.5 + 0.75s
16.2 - 13.5 = 0.75s
2.7 = 0.75s
s = 2.7 / 0.75
s = 3.6
S = 3.6
Hence the amount of silver needed per ring in other to reduce the gold content = 3.6g
Total for the 5 rings = (3.6 * 5) = 18g
Select the foods below that make up the 8 most common allergens.
Select all that apply and then click Submit.
Milk
Apples
Soda Pop
Peanuts
Soy
Nuts
Eggs
Fish
Reset
Chicken
Shellfish
Wheat
Broccoli
Search blue bottle experiment, read over the reaction, and explain why the colorless solution turns blue
and how it then turns back to colorless. answer
Answer:
An alkaline solution of glucose acts as a reducing agent and reduces added methylene blue from a blue to a colourless form.
Should your height be measured in meters or centimeters
Your height should be measured in meters. Centimeters is much too small of a unit to measure the several feet most people are.
In carbon dioxide (CO2), how many grams of oxygen (O) would there be if there are 24 grams of carbon (C)?
Answer:
64g of Oxygen
Explanation:
Firstly, carbon and oxygen react to form CO2 as follows;
C + O2 => CO2
According to the equation, one mole of C reacts with one mole of O2 to give one mole of CO2
Since molar mass of C= 12g/mol, O= 16g/mol
One mole of (C) contains 12g
One mole of O2 contains 16(2) = 32g
Hence, If there are 24g of C, there would be 24 × 32 / 12
= 768/12
= 64g
Hence, there would be 64g of oxygen if there are 24g of Carbon
What is the answer to this question
Answer:
hypothesis
Explanation:
a hypothesis is a prediction that you make about an experiment.
The accepted value for the molar volume of a gas is 22.4 L. Sarah’s experimental data indicated that a mole of a gas had a volume of 19.6L. What was her percent error?
Answer:
12.5%.
Explanation:
The following data were obtained from the question:
Accepted value = 22.4 L
Experimental value = 19.6L
Percentage error =.?
Percentage error can be obtained by using the following formula:
Percentage error = |Experimental value – Actual value | / actual value × 100
Percentage error = |19.6 – 22.4|/22.4 × 100
Percentage error = 2.8 /22.4 × 100
Percentage error = 280/22.4
Percentage error = 12.5%
Therefore, the percentage error of Sarah is 12.5%
Convert 3.48 Km into millimeters. The correct answer with correct units is:
A.)0.000000348M
B.)3. 4800 Mm
C.)3,480,000 mm
D.) 3, 480,000,000 mm
Answer:
C- 3480000mm
Explanation:
3480000mm
convert 0.00043 dam to hm
Which statements differentiate DNA and RNA? Check all that apply.
Answer:
A:DNA is a double helix, and RNA is a single strand.
C:DNA is involved only in transcription, and RNA is involved in both transcription and translation.
E:DNA does not have uracil as a nitrogen base, but RNA does have uracil as a nitrogen base.
Explanation:
I did the test an Edge.
Why was lake Lenore chosen
Answer:
Dude just watch the video
Explanation:
An object measures 6.2cm x 13.7cm x 26.9cm. Which value is the length of the object?
Answer:
Explanation:
The length is usually the longest side.
That would mean that 26.9 is the length.
Question 2
Which statement describes a change of matter that I DIFFERENT from the others?
A
Peroxide breaking down into water and oxygen
B
Bubbles forming when a pot of water is heated
A pair of jeans soaked in water drying after hanging outside
D
A block of ice decreating in size due to a change in temperature
Answer:
A. Peroxide breaking down into water and oxygen
Explanation:
Generally when it comes to changes, there are physical and chemical changes. In physical changes, there are no new substances been formed, however in chemical change new substances are formed.
A. Peroxide breaking down into water and oxygen
This is a chemical change.
B . Bubbles forming when a pot of water is heated
This is a physical change
C. A pair of jeans soaked in water drying after hanging outside
This is a physical change
D . A block of ice decreasing in size due to a change in temperature
This is a physical change.
Only option A is different from the rest,hence this is the answer.
PLEASE HELP I HAVE THIS TEST TOMORROW AM GIVING MORE POINTS THAN I SHOULD!
An unlit match contains approximately 1,000 J of chemical energy. When it burns, the match releases thermal energy and light energy. After it has burned, the remaining match contains 250 J of chemical energy. If the thermal energy was measured to be 400 J, how much light energy did the match emit?
Answer:
match emit 350 J light energy.
Explanation:
By law of conservation of energy, total energy before and after reaction for an isolated system remains constant.
Total energy for unlit match = 1000 j
When it burns type of energy released
thermal energy = 400 j
light energy --> it value is unknown which we have to find
also remaining match has 250 joule of chemical energy
applying law of conservation of energy
energy before match was unlit = energy after match was lit
1000 j = thermal energy + light energy + chemical energy of remaining match
1000 J = 400 J + light energy + 250 J
light energy = 1000 J - 400J - 250J
light energy = 350 J
Thus, match emit 350 J light energy.
0.15 m acetic acid/sodium acetate aqueous buffer at ph 4.5 is diluted to a concentration of 0.1 m with the addition of water what is the pH of the resulting buffered solution
Answer:
Explanation:
A mixture of a weak acid and its conjugate base (or a mixture of a weak base and its conjugate acid) is called a buffer solution, or a buffer. Buffer solutions resist a change in pH when small amounts of a strong acid or a strong base are added (Figure 1). A solution of acetic acid and sodium acetate (CH3COOH + CH3COONa) is an example of a buffer that consists of a weak acid and its salt. An example of a buffer that consists of a weak base and its salt is a solution of ammonia and ammonium chloride (NH3(aq) + NH4Cl(aq)).
The pH of the resulting buffer solution is 6.60.
How to calculate pH of acidic buffer solution?pH of acidic buffer solution is calculated by Henderson equation which is,
pH =pK[tex]_a[/tex] +log[salt]/log[acid]
As the buffer is diluted the concentration is reduced to half, that is
[acid]=0.075 M
[salt]=0.02 M pK[tex]_a[/tex]=4.74
substituting these values in Henderson's equation for acid buffers,
pH=4.74+log[0.075]/[0.02]
=6.6071
Thus, the pH of resulting buffer solution is 6.6071.
Acid buffers consist of a solution of weak acid and its salt.A commonly used acid buffer is prepared by mixing acetic acid and sodium acetate.
Henderson equation is used to calculate pH of buffer solution and ratio of salt to acid to prepare acid solution. pK[tex]_a[/tex] for acid buffers is constant.
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Which of the following is considered to be a chemical property of matter?
Answer: Meteorhpayne
Explanation: Correct me if im wrong :(
Q: A wind-up toy that is not wound up...
(drag the check on one)
does not have energy.
has potential energy.
has kinetic energy
has both kinetic and potential energy
S
A wind-up toy that is not wound up will have Potential Energy Hence, The correct option is Option (B)
What is potential energy ?Potential energy is that the energy control by associate object due to its position relative to alternative objects, stresses among itself, its charge, or alternative factors.
The total energy of a mechanical toy is given as follows ;
Total Mechanical Energy = Kinetic Energy + Potential Energy
During the winding up of the coil, the total energy becomes the kinetic energy
The total energy at the point of winding up of the coil = The kinetic energy supplied to the toy by winding the coil
From the first law of thermodynamics, energy can not be created nor destroyed however may be modified from one type to a different
Due to the coil being prevented from unwinding, the kinetic energy stored as Potential energy of the toy
When the toy is operated it then unwinds the coil bringing about motion and converting back the potential energy to kinetic energy by itself as if it was alive.
Therefore, A wind-up toy that is not wound up will have Potential Energy Hence, The correct option is Option (B)
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Frank drank 2 liters of soda. How many mL of soda did he drink?
Answer:
2000 mL
Explanation:
1 L = 1000 mL
Therefore,
2 L = 2 x 1000 mL = 2000 mL
In a chemical processing plant, a reaction chamber of fixed volume V0 is connected to a reservoir chamber of fixed volume 4V0 by a passage containing a thermally insulating porous plug. The plug permits the chambers to be at different temperatures. The plug allows gas to pass from either chamber to the other, ensuring that the pressure is the same in both. At one point in the processing, both chambers contain gas at a pressure of 1.00 atm and a temperature of 27.0°C. Intake and exhaust valves to the pair of chambers are closed. The reservoir is maintained at 27.0°C while the reaction chamber is heated to 400°C. What is the pressure in both chambers after that is done? 50. Why is the following situation impossible?
Answer:
Explanation:
The two chambers are at temperature of 27° and pressure of 1 atm . Now temperature of second chamber is increased to 400°C so its pressure will be increased but pressure of chamber whose temperature remains at 27°C will remain unaltered . Hence the pressure of chamber at 27°C will be at 1 atm.
The volume of second chamber is 4 V₀ , temperature changed from 27 + 273 = 300 k to 400 + 273 = 673 K , initial pressure was 1 atm . Let final pressure be P
From gas law formula
1 x 4 V₀ / 300 = P x 4 V₀ / 673
P = 1 x 673 / 300
= 2.24 atm .
The pressure of the chamber at 400°C will be 2.24 atm.
An air mass that originates over land in central america is most likely
Answer: An air mass that originates over land in Central America is most likely warm & dry.
A true statement about mass is that
A. as the force of Earth's gravity on an object increases the object's mass increases.
B. mass is expressed in pounds
C. mass if often measured with a spring scale. D. mass is determined by comparing the mass of an object with a set of standard masses tha catalanse
Answer:
d
Explanation:
A: mass never increases or decreases. It is a value that is the same everywhere in the universe. A is not correct.
B: it can be but that is not the only unit that can be used
C: A spring scale measures force not mass.
D: The answer to this question is D if the word at the end is balance.
If you drop an object with a mass of 3.66 grams and a volume of 4 mL into a beaker containing dish soap, would it float or sink? Dish soap has a density of 0.93 g/mL
While burning coal and charcoal, you notice that coal releases more heat than charcoal. That means that the... 1. elastic energy 2.gravitational energy 3.chemical potential energy is 1.lower 2. higher in charcoal than in coal
Answer:
3). Chemical potential energy
1). lower in charcoal than in coal.
Explanation:
Chemical potential energy is defined as the energy that can be absorbed or stored in a substance's chemical bonds. It can be released when there is a change in the number of particles of the substance.
As per the question, coal releases more heat than charcoal because 'the chemical potential energy of charcoal is lower than the coal' and hence, the latter would release more heat on burning i.e. the energy that was absorbed in the chemical bonds of the substance. Hence, option 3 and 1 are the correct answers.
Scientific predictions can best be described as: a Problems you expect to identify b Questions you expect to ask c Experiments you expect to run d Evidence you expect to find
Answer:
Explanation:a
Scientific predictions are best described as consistent data that are presented in the form of if and then. It is a solution to the problem that may be identified. Thus, option a is correct.
What is scientific prediction?Scientific prediction is a statement that describes the events of the future that are not always correct or incorrect. In scientific research, the experiment is conducted based on the hypothesis to draw conclusions and results that are expected.
The expected results are said to be scientific predictions when they are represented in the form of "if and then" before the analysis of the experimental method and its result are done. It is an account of the events that may possibly take place under specific conditions.
Therefore, option A. scientific prediction is an expected problem.
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HELP BRAINLIESTTTT
What best describes the bonding in a water molecule? (1 point)
a
An oxygen atom shares an electron pair with each H atom.
b
An oxygen atom shares a single electron with each H atom.
c
An oxygen atom receives an electron from each H atom.
d
An oxygen atom transfers an electron to each H atom.
Answer:
l guess c is the answer
Explanation:
it is true because in oxygen does not share any atoms with hydrogen
Answer:
A
Explanation:
taking test currently
iron is a metal that rusts in the presence of oxygen and water. mild steel is used for ...1... and is prevented from rusting by ...2...chemistry igcse
Answer and Explanation:
Used as a construction frame material and for bending metal works because they are rigid and strong.Galvanising or coating the surface would prevent rusting.N.B.: Mild steel is steel that has low carbon content, also called carbon steel.
I hope this explanation was helpful.
Answer:
car bodiespaintingExplanation:
Mild steel is used in making car body parts because it is malleablePainting mild steel prevents moisture and oxygen from reaching the metalWhich of these describes a natural phenomenon or relationship that always occurs under specific conditions a) theory b) law Group of answer choices
Answer:
B). Law
Explanation:
A law is defined as the statement of an observed order, sequence, or relationship of a natural phenomenon which is invariable or always true under certain specific conditions while the theory is characterized as the explanation of this observed phenomenon and prediction of the new facts or phenomenon which was previously not observed to set out the new laws or principles of something. Thus, the theory is the base for the formation of law and hence, option B is the correct answer.
Define Chemotherapy
Explanation:
the treatment of disease by the use of chemical substances, especially the treatment of cancer by cytotoxic and other drugs.