Answer:
Chlorine gas is produced
Explanation:
One of the methods of laboratory preparation of chlorine gas is to heat manganese dioxide with concentrated hydrochloric acid. The acid is oxidized by the manganese dioxide to liberate chlorine gas as follows;
MnO2(s) + 4HCl(aq) -------> MnCl2(aq) + 2H2O(l) + Cl2(g)
Hence, When manganese dioxide is heated with concentrated hydrochloric
acid, chlorine gas is liberated.
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(11) Deduce the number of dyes in food colouring H.
(iii) Suggest why food colouring F does not move during the experiment.
(iv) Explain which two food colourings contain the dye that is likely to be the most soluble the solvent.
(b) Determine which food colouring contains a dye with R, value closest to 0.67
Show your working.
Answer:
(ii) 1 dye
(iii) Food coloring F is insoluble in the solvent
(iv) 'E' and 'H'
(b) Food colouring G
Explanation:
Paper chromatography principle is based on the rates of migration of chemicals across a sheet of paper which are different and it consists of a stationary phase such as the water in the paper and a mobile phase such as the solvent resulting in the partitioning of the components of the mixture across the paper
The solution components are positioned to start in one place from where they migrate and separate out on the chromatography paper
(ii) The number of components into which the food colouring 'H' separates into = 1
Therefore, the number of dyes in food colouring 'H' = 1 dye
(iii) Food coloring 'F' does not move because it is insoluble in the solvent, which is the mobile phase
(iv) The food colouring that contains the dye that is likely to be most soluble in the solvent are does for which the dyes travel furthest, which are;
Food coloring 'E' and 'H'
(b) Using a similar question solution found on 'tutor my self' website, we have;
The [tex]R_f[/tex] values are given as follows;
[tex]R_f = \dfrac{Distance \ moved \ by \ dye}{Distance \ moved \ by \ solvent}[/tex]
The distance moved by the solvent = 5 units
The distance moved by dyes in food colouring 'E' and 'H' = 4 units
The distance moved by dye in food colouring 'G' = 3.3 units
The distance moved by the second dye in food colouring 'E' = 2.7 units
By inspection, we get;
[tex]R_f[/tex] dye in food colouring 'G' = 3.3/5 = 0.66,
Therefore, the dye with [tex]R_f[/tex] value closest to 0.67 is the dye in food colouring 'G'.
(hurry pls)Carl plugs in a lamp that has 0.67 of resistance and 8.1 volts running through it. What is the amount of current running through the lamp? C 543 A C 0.08 A C 12.09 A C743 A
Answer:
C)12.09 Ampere
Explanation:
V= IR
Where I= current of the system
R= resistance= 0.67 ohm
V= potential difference=8.1 volts
Substitute the values
8.1= I× 0.67
I= 8.1/0.67
=12.09 Ampere
What are the two limitations of earth plates
Answer:
The tectonic style and viability of modern plate tectonics in the early Earth is still debated. Field observations and theoretical arguments both in favor and against the uniformitarian view of plate tectonics back until the Archean continue to accumulate. Here, we present the first numerical modeling results that address for a hotter Earth the viability of subduction, one of the main requirements for plate tectonics. A hotter mantle has mainly two effects: 1) viscosity is lower, and 2) more melt is produced, which in a plate tectonic setting will lead to a thicker oceanic crust and harzburgite layer. Although compositional buoyancy resulting from these thick crust and harzburgite might be a serious limitation for subduction initiation, our modeling results show that eclogitization significantly relaxes this limitation for a developed, ongoing subduction process. Furthermore, the lower viscosity leads to more frequent slab breakoff, and sometimes to crustal separation from the mantle lithosphere. Unlike earlier propositions, not compositional buoyancy considerations, but this lithospheric weakness could be the principle limitation to the viability of plate tectonics in a hotter Earth. These results suggest a new explanation for the absence of ultrahigh-pressure metamorphism (UHPM) and blueschists in most of the Precambrian: early slabs were not too buoyant, but too weak to provide a mechanism for UHPM and exhumation.
Explanation:
Meera added blue copper sulphate crystals to some water in a beaker.
The copper sulphate dissolved in the water.
1 give one way meera could see that the copper sulphate had dissolved in the
Answer:
The solid crystals disappeared
Explanation:
When a soluble solid solute is added to water, the solid solute disappears after a little while. The disappearance of this solute indicates that the solute has been dissolved in water.
In this case, blue copper sulphate crystals are added to water, the blue crystals disappear leaving only a blue solution. The disappearance of these blue copper sulphate crystals indicates that the substance has dissolved in water.
Based on information from the periodic table, which statement is true for the
element cobalt?
Answer: (A) a cobalt atom contains 27 protons, and most cobalt atoms contain 32 neutrons.
Explanation: just answered the question and that was the correct answer
Answer: The answer is : A cobalt atom contains 27 protons and MOST neutral cobalt atoms contain 32 electrons
Explanation: I took the test
what do mars, pluto, and Jupiter have in common (science) in 8th grade.
Answer:
they are all planets
Explanation:
You are given 250 mL of a 12.0 M solution of KNO3. To obtain a 5.0 M, to what volume does the solution need to be diluted to?
600 ml
104.17 mL
0.24 mL
60 mL
Answer:
600 mL
Explanation:
molarity 1 * volume 1 = molarity 2 * volume 2. So this means 12 * 250 = 3000 and divide that by 5 to get 600 mL.
Find the hydroxide concentration of a LiOH soultion that has a pOH of 8.65.
[OH] = _____ (round to 2 decimal places)
Answer: i need help
Explanation:
17 moles of oxygen is equals to how many grams
17 × ( 2 × 16 ) = 17 × 32 = 544 grams
___________________________
Use the given Nernst equation and reaction to solve this problem. What is the potential of this cell with the given conditions?
2Li (aq) + F2(g) 2Li+(aq) + 2F- (aq)
E° = +5.92 volts
T = 200°C
[Li+] = 10.0 molar
[F-] = 10.0 molar
Answer:
The 2nd one is the one
Explanation:
and it isn't writen out all the way
What is the mass of disulfur pentoxide (S2O5)?
Answer: What is the mass of disulfur pentoxide (S2O5)?
Explanation:144.14g/mol
Select the correct structure that
corresponds to the name.
2,2-dimethyl-3-hexyne
A. CH3CH2C=CC(CH3)3
B. CH3CH(CH3)C = CCH(CH3)2
C. both
Answer: A
Explanation:
The correct structure of the name of the compound given is CH₃CH₂C=CC (CH₃)₃.
What is 2,2-dimethyl- 3- hexyne?Dimethyl hexyne is an organic compound. Its chemical formula is C8H14. The compound hexyne is used to make a complex compound, agrochemical, and pharmaceutical compounds.
Thus, the correct option is A, CH₃CH₂C=CC (CH₃)₃.
Learn more about 2,2-dimethyl- 3- hexyne
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Which of the following statements about alkynes is incorrect?
Alkynes are unsaturated hydrocarbons.
Alkynes have triple bonds.
Alkynes are saturated hydrocarbons.
Alkynes have carbon atoms.
Answer:
Alkynes are saturated hydrocarbons
Explanation:
Alkynes are groups of hydrocarbons that have the general formula of {Cn H2n - 2}. They have a triple carbon to carbon bond (C≡C) in their structure. Ethyne (HC≡CH) is the first member of the alkyne series.
Alkynes like alkenes are unsaturated hydrocarbons because of their triple and double carbon bonds respectively. Unsaturated hydrocarbons do not have a complete hydrogen atom in their structural composition. Hence, the statement that "Alkynes are saturated hydrocarbons" is FALSE.
how many atoms are in 4.5 moles of Al?
Explanation:
4.5×6.022×10²³
27.099×10²³
According to Avogadro's number, there are 27.10×10²³ atoms in 4.5 moles of Al.
What is Avogadro's number?Avogadro's number is defined as a proportionality factor which relates number of constituent particles with the amount of substance which is present in the sample.
It has a SI unit of reciprocal mole whose numeric value is expressed in reciprocal mole which is a dimensionless number and is called as Avogadro's constant.It relates the volume of a substance with it's average volume occupied by one of it's particles .
According to the definitions, Avogadro's number depend on determined value of mass of one atom of those elements.It bridges the gap between macroscopic and microscopic world by relating amount of substance with number of particles.
Number of atoms can be calculated using Avogadro's number as follows: mass/molar mass×Avogadro's number.As 1 mole =6.023×10²³ atoms , thus,4.5 moles =4.5×6.023×10²³ = 27.10×10²³ atoms.
Thus, there are 27.10×10²³ atoms in 4.5 moles of Al.
Learn more about Avogadro's number,here:
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what is the name of the shape that is a quadrilateral where all 4 sides are the same length
HELP QUICK
Answer:
Square
Explanation:
A square is a quadrilateral with r sides the same length
Ammonia gas (NH3) combines with oxygen gas (O2) to form diatomic nitrogen gas and water vapor. If 4.0 grams of ammonia react, how many liters of nitrogen gas are produced? The gas is collected at 32.00°C and a pressure of 2.6 atmospheres.
Answer:
1.13 L
Explanation:
First, we have to write the chemical equation for the reaction between ammonia gas (NH₃) and oxygen gas (O₂) to give nitrogen gas (N₂) and water (H₂O), as follows:
NH₃(g) + O₂(g) → N₂(g) + H₂O(g)
Then, we have to balance the equation (we write first the coefficient 2 for NH₃ to balance N atoms, then a coefficient of 3 for H₂O to balance H atoms, and finally 1/3 to balance the O atoms):
2 NH₃(g) + 3/2 O₂(g) → N₂(g) + 3 H₂O(g)
In the balanced equation, we can see that 1 mol of N₂ is produced from 2 moles of NH₃. We convert the moles of NH₃ to grams by using its molecular weight (MW):
MW(NH₃) = 14 g/mol N x 1 + (1 g/mol H x 3) = 17 g/mol
grams of NH₃ = 17 g/mol x 2 = 34 g
Thus, we have the stoichiometric ratio:
1 mol of N₂/2 mol NH₃ = 1 mol of N₂/34 g NH₃
To calculate how many moles of N₂ are produced from 4.0 of NH₃, we multiply the mass by the conversion factor:
4.0 g NH₃ x 1 mol of N₂/34 g NH₃ = 0.1176 moles N₂
Finally, we calculate the liters of N₂ gas by using the ideal gas equation:
PV = nRT ⇒ V = nRT/P
We introduce the data in the equation:
T = 32.00°C + 273 = 305 K
P = 2.6 atm
R = 0.082 L.atm/K.mol (is the gas constant)
n= 0.1176 moles
⇒ V = nRT/P = (0.1176 mol x 0.082 L.atm/K.mol x 305 K)/(2.6 atm)
= 1.13 L
When carbon disulfide, CS2, forms from its elements. Heat is absorbed. How much heat would be required to produce 5.0 moles of carbon disulfide
Answer:
5.9 × 10² kJ
Explanation:
When carbon disulfide, CS₂, forms from its elements, heat is absorbed. The corresponding value for the standard enthalpy of formation of carbon disulfide is 117.36 kJ/mol. The thermochemical equation that represents this process is:
C(graphite) + 2 S(s, rhombic) ⇒ CS₂(g) ΔH°f = 117.36 kJ/mol
117.36 kJ of heat are absorbed when 1 mole of CS₂ is formed. The amount of heat absorbed when 5.0 moles of CS₂ are formed is:
5.0 mol × 117.36 kJ/mol = 5.9 × 10² kJ
(10 POINTS!!!!!!!!!!!
What environmental change will take place when harmful substances get into the food and water supply of animals or plants?
A Climate change
B Increased predators
C Lack of food
D Pollution
need asap
Answer:
A climate change
Explanation:
the surrounding area would be effected in all ways imaginable, such as change in air, soil, water, plants, animals. and if you eat those said animals those harmful things can transfur into you
if an atom has 4 protons, 5 neutrons, and 4 electrons, what would its atomic mass be?
Answer:
4
Explanation:
If I remember correctly, the atomic # will always be the same as the # of electrons
What volume of water is needed to make 5.41 M solution with 47.71 moles of HCL?
Answer:
0.113 liters
Explanation:
5.41 M / 47.71 moles = 0.113 liters
what does the period number on the periodic table tell us?
Answer:
The period number on the Periodic table tells you the total number of orbits that the atom will have. In other words, the period number indicates the number of energy levels (or energy orbit) of an atom. For example, 1st period indicates that these elements possess 1 energy shell (or energy orbit).
Explanation:
why do we need to rinse the mouth before collecting the saliva
5). At what temperature (K) will 0.854 moles of neon gas occupy 12.3 L at 1.95
atmospheres?
Answer:
338.38 K
Explanation:
Applying,
PV = nRT............... Equation 1
Where P = pressure, V = Volume, R = Temperature, n = number of moles, T = temperature.
Make T the subject of the equation,
T = PV/nR............. Equation 2
From the question,
Given: P = 1.95 atm, V = 12.3 L, n = 0.854 moles
Constant: R = 0.083 L.atm/K.mol
Substitute these values into equation 2
T = (1.95×12.3)/(0.854×0.083)
T = 338.38 K
How would you find the density of a can of soda pop?
A. Find the mass of the can of soda pop and then multiply by the number of cubic centimeters in the can
B. Find the mass of the can of soda pop and then divide by the number of cubic centimeters in the can
C. Convert a gallon into cubic centimeters and then divide by the mass of the can of soda pop
D. Convert a gallon into cubic centimeters and then subtract the mass of the can of soda pop
Answer:
it's A.
Explanation:
have uh good day ma :)))))))
How many moles of aluminum are in 54 grams
What will the change in temperature be when 90 J are applied to 15 g of gold. (Cgold = 0.126 J/gºC)
Round your answer to the nearest whole number.
°C
E
3
4
5
Next
O
I 17
Answer:
48 °C
Explanation:
q = 90J
m = 15 g
C = 0.126 J/gºC
q = mct
90 = (15)(0.126)t
t = 47.62 °C = 48 °C
Answer:
Explanation:
Formula
E = m * c * Δt
Δt is what you seek.
Givens
E = 90 joules
m = 15 grams
c = 0.126
Solution
90 = 15 * 0.126 * Δt Divide by 15
90/15 = 15/15 * 0.126 * Δt
6 = 0.126 * Δt Divide by 0.126
6/0.126 = Δt
47.619 = Δt
Δt = 48 oC
Potassium hydroxide is partially soluble as shown by the
following reaction:
KOH(s) K+ (aq) + OH(aq)
What is the poH of a 3.32 x 10-5 M KOH solution?
pOH =
Your answer should be rounded to three significant figures. Do not Include
units in your answer.
Answer: 4.48 or 4.47
¿Cómo se llama el grupo IIA de la tabla periódica?
Answer:
los metales alcalinotérreos: berilio (Be), magnesio (Mg), calcio (Ca), estroncio (Sr), bario (Ba) y radio (Ra).
o simplemente llamado grupo 2A
Explanation:
Four satellites are in orbit around the Earth. The heights of their four orbits
are identical. The masses of the four satellites are given in the table. For
which satellite is the gravitational pull of Earth the strongest?
What is the frequency of a wave that has a wavelength of 0.50 m and a speed of 380 m/s?
Answer: f = 760 Hz
Explanation: speed = frequency · wavelength v = fλ.
frequency f = v/ λ = 380 m/s / 0.50 m = 760 Hz