Rafiq should expose one piece under the lamp for 10 days while keeping the other in the darkness.
What are the elements in this experiment?In this experiment, it is essential to have a control group and an experimental group.
Control group: This is the population that does not receive a "treatment" or in this case the piece of fabric that is not exposed to light. It is essential to have this element because it works as a reference.Experimental group: This is the population that receives a special "treatment" or in this case the piece of fabric that must be exposed to light to test if there is a color change.Which experiment design is the best for Rafiq?Based on the previous ideas, the best for him is to keep one piece of clothing in the darkness (control group), while exposing the other to the light of the lamp (experimental group).
In this way, he can determine if there is a real change of color by comparing both pieces after 10 days.
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Where are chlorofluorocarbons (CFCs) found? Why were they banned?
Answer:
A gaping hole in the ozone layer over Antarctica was discovered in the mid 1980s. The international community agreed the Montreal Protocol in 1987, which banned most of the offending chemicals.
Hope this helps..what is the boiling point of a 0.321 m aqueous solution of NaCl. Enter your rounded answer with 3 decimal places.
Answer:
∆T = imK
∆T = Change in boiling point (B.P.)
i = van't Hoff factor = 2 for NaCl (Na+ and Cl2_
m = molality = 0.321 m
k = boiling point constant for water = 0.512 deg/m
∆T = (2)(0.321)(0.512) = 0.329 degrees
Since the normal B.P. for water is 100ºC, the new boiling point of this solution is 100 + 0.329 = 100.329ºC
So Our Answer is 100.329ºC
The boiling point of the 0.321 m NaCl solution has been 100.329 degrees Celsius.
The boiling point has been defined at the temperature at which the liquid started to convert to gas.
The van't Hoff factor has been a value of the number of ions formed by the dissociation of 1 formula unit of a compound.
The change in the boiling point of the sample, ([tex]\Delta T[/tex]) has been given by:
[tex]\Delta T=imK[/tex]
Where, the van't Hoff factor for NaCl, i =-2
The molality of the sample, m =0.321 m
The boiling point constant of water, [tex]K=0.512\;^\circ m^-^1[/tex]
Substituting the values for change in temperature ([tex]\Delta T[/tex]):
[tex]\Delta T=2\;\times\;0.321\;\times\;0.512\;^\circ C\\\Delta T=0.329\;^\circ C[/tex]
The change in the temperature of the water on the addition of NaCl has been 0.329 degrees Celsius.
The initial temperature of the water has been 100 degrees Celsius. The new temperature (T) of the NaCl solution has been:
[tex]T=100\;+\;0.329\;^\circ \text C\\T=100.329\;^\circ \text C\\[/tex]
The new boiling point of the NaCl solution has been 100.329 degrees Celsius.
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Cylinder A and Cylinder B are sealed, rigid cylinders with movable pistons. Each cylinder contains 500. milliliters of a gas sample at 101.3 kPa and 298 K. Cylinder A contains H2 and cylinder B contains N2. Explain, in terms of collisions between gas molecules and the walls of the container, why pushing the movable piston farther into cylinder B at constant temperature would increase the pressure of the N2 gas.
Answer:
The pressure of N₂ gas in cylinder B when compressed at constant temperature increases due to the increase in the frequency of collision between the gas molecules with themselves and with the wall of their container caused by a decrease in volume of the container.
Explanation:
Gas helps to explain the behavior of gases when one or more of either temperature, volume or pressure is varying while the other variables are kept constant.
In the gas cylinder B, the temperature of the given mass of gas is kept constant, however, the volume is decreased by pushing the movable piston farther into the cylinder. According to the gas law by Robert Boyle, the volume of a given mass of gas is inversely proportional to its pressure at constant temperature. This increase in pressure is due to the increase in the frequency of collision between the gas molecules with themselves and with the wall of their container caused by a decrease in volume of the container. As the cylinder becomes smaller, the gas molecules which were spread out further become more packed closely together, therefore, their frequency of collision increases building up pressure in the process.
In terms of collisions between gas molecules and the walls of the container, the reason why pushing the movable piston farther into cylinder B at constant temperature would increase the pressure of the N2 gas is due to the fact that;
The movement of the piston farther into the cylinder would lead to an increase in the number of collisions per unit area between the N2(nitrogen) molecules and the internal walls of the cylinder. The movement described above would lead to creation of greater pressure because the more the collisions, the higher the pressure.The image showing the two cylinders are missing and so i have attached it.
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Worth 50 points. Please answer correctly
Answer:
question 2 is false
Explanation:
6 is D
2CuO+2NH3------ 3Cu + 3H2O+ N2. Given that the relative molecular mass of copper oxide is 80, what volume of ammonia is required to completely reduce 120 g of Copper oxide? ( Cu=64, O=16, N=14)
Volume of Ammonia(NH₃) = 22.4 L
Further explanationGiven
Reaction
3CuO+2NH₃⇒ 3Cu + 3H₂O+ N₂
In the problem, the CuO coefficient should be 3 not 2
M CuO = 80
mass CuO = 120 g
Required
The volume of NH₃
Solution
mol CuO :
[tex]\tt mol=\dfrac{mass}{M}\\\\mol=\frac{120}{80}\\\\mol=1.5[/tex]
From the equation, mol ratio CuO : NH₃ = 3 : 2, so mol NH₃=
[tex]\tt \dfrac{2}{3}\times 1.5=1~mol[/tex]
Assume at STP(0 °C, 1 atm) ⇒1 mol = 22.4 L, then volume of NH₃=22.4 L
Convert each into decimal form. a) 1.056 x 10-3 b) 0.560 x 102
Answer:
A. 7.56
b. 57.12
Explanation:
Hope that's right have a nice day :)
A chipmunk (mass of approximately 1 kg) does push-ups by using a force of 5 N to elevate its center-of-mass by 6 cm in order to do 0.70 Joule of work. If the chipmunk does all this work in 2 seconds, what is its power?
Answer:
Approximately [tex]0.35\; \rm W[/tex] on average.
Explanation:
There are multiple to find power:
Power [tex]P[/tex] is equal to the product of force [tex]F[/tex] and the speed [tex]v[/tex] at which that force moves the object. That is: [tex]P = F \cdot v[/tex].On the other hand, average power [tex]P[/tex] is also equal to the rate at which work [tex]W[/tex] is done. In other words, average power [tex]P\![/tex] is the average work done in unit time. If work [tex]W\![/tex] is done in time [tex]t[/tex], the average power would be [tex]P = W / t[/tex].The question did not state the speed at which the arm of the chipmunk moves. However, the question did state the work done ([tex]W = 0.70\; \rm J[/tex]) and the time required ([tex]t = 2\; \rm s[/tex]).
Therefore, the equation [tex]P = W / t[/tex] seem to be more suitable.
[tex]\begin{aligned}&P\\ &= \frac{W}{t} \\ &= \frac{0.70\; \rm J}{2\; \rm s} \approx 0.35\; \rm W\end{aligned}[/tex].
which equation represents the process of cellular respiration?
Answer:
C 6 H 12 O 6 + 6 O 2 --> 6 CO 2 + 6 H 2 O + ATP is the complete balanced chemical formula for cellular respiration.
Answer:
C6H12O6 + 6O2 -> 6CO2 + 6H2O + 38ATP
Explanation:
glucose + oxygen gas -> carbon dioxide + water + ATP
Write the formula iron 11 bromide
Answer:
FeBr2
Explanation:
this isn't really an explanation but it's helpful so here, iron(II) bromide is an inorganic compound with the chemical formula FeBr₂. The anhydrous compound is a yellow or brownish-colored paramagnetic solid. Several hydrates of FeBr₂ are also known, all being pale colored solids.
How many grams are in 2.5 moles of PO4?
Cooks sometimes marinate meat in liquid before cooking, which helps soften the meat and adds flavor. A cook places a whole
steak and 16 oz. of marinating liquid in a bowl, and then marinates the mixture overnight in the refrigerator. Many changes would
* speed up this rate of marination. Which of these would slow it down?
Answer:D
Explanation:
Answer:
C) adding 16 oz. of water to the marinating liquid
Explanation:
Adding 16 oz. water to the marinating liquid would decrease the concentration of the marinating liquid and slow down the rate of reaction. The other answer choices would increase the rate of reaction.
NEEED HELP ASAP
Metals are ductileYou can pull or draw them into a wire. The ductility of a material is a / a *
A) chemical property
B) extensive property C)intensive property
D) reactive property
which atmospheric gas is used by plants and given off by animals
What is the correct order of the scientific method?
Answer:
make an observationask questionsform a hypothesispredict your hypothesistest your hypothesis predictionmake new modifications to your hypothesis (repeat the steps)Explanation:
I hope this helps! :)))
PLZ HELP ASAP THIS IS DUE LIKE RIGHT NOW
Answer:it's either the first or second one
Explanation:
the layers of the earth
How many moles of helium gas are present in 120 liters of STP
96.5 grams of gold has a volume of 5 cm, what is the density of gold?
Answer:
9.3
Explanation:
The first thing to do to solving this problem is putting mass over volume, 96.5g / 5cm^3. When you divide, you should get 1. Hope I helped.
manganese atom has 30 neutrons and atomic number 25
determine the electron cloud charge of manganese
Answer:
25
Explantion:
atomic no. = no. of eletron
Hydrogen gas is trapped by water displacem ent in a test tube at 25 o C and left to sit until vapor -liquid equilibrium is reached. The total pressure of the trapped gas in th e test tube is 102.0 kPa. What pressure is exerted by the hydrogen gas that was trapped over water?
Answer:
Therefore, the pressure exerted by the hydrogen gas that was trapped over water is 108.8 kPa
Explanation:
The law of partial pressure by Dalton, in a mixture of gases which do not react chemically together, the total pressure is equal to the sum of the partial pressures of the individual gases.
According to this law, the total pressure exerted by the gases above the displaced water is equal to the sum of the partial pressure of water vapor and the partial pressure of hydrogen gas: Ptotal = pH₂ + pH₂O
Therefore, pH₂ = Ptotal - pH₂O
Vapor pressure of water at 37°C = 3.17 kPa; Ptotal = 102.0 kPa
pH₂ = (102.0 - 3.17) kPa
pH₂ = 98.8 kPa
Therefore, the pressure exerted by the hydrogen gas that was trapped over water is 108.8 kPa
I need help with chemistry question?
Answer:
2Al + 3Na2SO4 -----> Al2(SO4)3 + 6 Na
Explanation:
Product should be Al2(SO4)3
Because Al contains +3 charge
And SO4 contains -2 charge
To balance this postive and negative charge we multiple +3 with 2 and -2 with 3
Ratan started business with cash Rs 50000
Answer:
what's the question here then ?????
Explanation:
nepal ????
Consider the balanced chemical
reaction below. When the reaction was
carried out, the calculated theoretical
yield for iron was 365 grams, but the
measured yield was 278 grams. What
is the percent yield?
Fe2O3 + 3C0 2Fe + 3C02
Explanation:
Percentage yield = (278/365) * 100% = 76.16%.
Answer:
[tex]\boxed {\boxed {\sf 76.2 \% }}[/tex]
Explanation:
A percent yield helps measure how successful or precise a reaction was. It is ratio of measured yield to theoretical yield as a percent. The formula is:
[tex]percent \ yield=\frac{actual \ yield}{theoretical \ yield } *100[/tex]
For this reaction, the measured/actual yield was 278 grams, while the theoretical yield was 365 grams.
[tex]actual = 278 \ g \\\theoretical= 365 \ g[/tex]
Substitute the values into the formula.
[tex]percent \ yield =\frac{278 \ g}{365 \ g} *100[/tex]
Divide first. The grams (g) will cancel out.
278 g/365 g= 278/365=0.7616438356[tex]percent \ yield =0.76164383561*100[/tex]
Multiply.
[tex]percent \ yield=76.1643835616[/tex]
The original measurements both had 3 significant figures, so we should round our percent yield to 3 sig figs. In this case, that is the tenths place.
The 6 in the tenth place tells us to round the 1 up to a 2.
[tex]percent \ yield \approx 76.2[/tex]
The percent yield is about 76.2 %
SOMEONE HELP ME PLEASE ILL GIVE BRAINLY
Answer:
true
Explanation:
just did it
Use the periodic table to identify the number of valence electrons available for bonding for each of the following elements.
Answer: Edgy, 2020
Explanation: <3
Answer:
refer to picture below :)
Explanation:
What is the molecular formula of the molecule that has an empirical formula of CH2O and a molar mass of 120.12 g/mol
Answer:
C4H8O4
Explanation:
Let (CH20)x
C=1*12.01=12.01 (12.01, 1.01, 16.00 Avg mass of elements)
H=2*1.01=2.01
O=1*16.00=16.00
12.01 + 2.01 + 16.00 = 30.03
120.12/30,03=4
==> (CH2O)4 = C4H8O4
The molecular formula of the molecule that has an empirical formula of [tex]CH_2O[/tex] is equal to [tex]C_4H_8O_4[/tex].
Given the following data:
Empirical formula = [tex]CH_2O[/tex]Molar mass = 120.12 g/mol.Scientific data:
Molar mass of oxygen = 16 g/mol.Molar mass of hydrogen = 1 g/mol.Molar mass of carbon = 12 g/mol.To determine the molecular formula of the molecule that has an empirical formula of [tex]CH_2O[/tex]:
First of all, we would find the molar mass of [tex]CH_2O[/tex]:
[tex]CH_2O =12 +(1\times2)+16\\\\CH_2O =30\;g/mol[/tex]
For molecular formula:
[tex](CH_2O)n = 120.12\\\\30n = 120.12\\\\n=\frac{120.12}{30}[/tex]
n = 4.0
[tex](CH_2O)_4 = C_4H_8O_4[/tex]
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Apple juice can be classified as which of the following?
O A compound
An Element
O A mixture
O A pure substance
Answer:
mixture
Explanation:
Answer:
Mixture
Explanation:
1. A 50 gram sample of a radioisotope decays to 12.5 grams in 14.4 seconds. What is
the half-life of this isotope?
Answer:
Half life = 7.2 seconds
Explanation:
[tex]from \: decay \: equation \\ 2.303 log( \frac{n.}{nt} ) = kt \\ 2.303 log( \frac{50}{12.5} ) = k \times 14.4 \\ k = \frac{2.303 log( \frac{50}{12.5} )}{14.4} \\ k = 0.096288 {s}^{ - 1} \\ since \: half \: life = \frac{ ln(2) }{k} \\ half \: life = \frac{ ln(2) }{0.096288} \\ half \: life = 7.2 \: seconds[/tex]
How many moles of oxygen are in a sample of 29.1 moles of coal (C135H96O9NS)?
Answer:
2.19moles
Explanation:
mole = mass ÷ molar mass
Molar Mass of the compound, C135H96O9NS =
12(135) + 1(96) + 16(9) + 14 + 32
= 1620 + 96 + 144 + 14 + 32
= 1906g/mol
Next, we calculate the mass percent of Oxygen in the compound
O9 = 16(9) = 144g/mol
144/1906 × 100
= 0.0755 × 100
= 7.55%
This means that there are 0.0755g of Oxygen in 1 mole of the coal compound.
Hence, in 29.1 moles of coal, there would be 29.1 × 0.0755
= 2.19moles of Oxygen
What chemical process occurs in cells to release energy?
A.
Oxidation
B.
Respiration
C.
Pespiration
D.
Nutrition
Answer:
B. Respiration
Explanation:
cellular respiration is the process where cells use glucose (C6H12O6) and oxygen gas (O2) to make carbon dioxide (CO2) water (H2O) and ATP, which is energy
formula:
C6H12O6 + 6O2 -> 6CO2 + 6H20 + 38ATP
If 4.2 g of water is actually produced, what is the percent yield?
Answer:
23.33%
Explanation:
from
percent yield=(mass÷total mass )×100%