Answer:
[tex]\rm MgBr_2 \cdot 6\, H_2O[/tex].
Explanation:
Let [tex]x[/tex] denote the number of [tex]\rm H_{2}O[/tex] formula units for every [tex]\rm MgCl_{2}[/tex] formula unit. The formula of the hydrate would be [tex]{\rm MgBr_2} \cdot x\, {\rm H_2O}[/tex].
Look up the relative atomic mass of each element on a modern periodic table:
[tex]\rm Mg[/tex]: [tex]24.305[/tex].[tex]\rm Br[/tex]: [tex]79.904[/tex].[tex]\rm H[/tex]: [tex]1.008[/tex].[tex]\rm O[/tex]: [tex]15.999[/tex].Formula mass:
[tex]\begin{aligned}M({\rm MgBr_{2}}) &= 24.305 + 2 \times 79.904 \\ &= 184.113\; \rm g\cdot mol^{-1}\end{aligned}[/tex].
[tex]\begin{aligned}M({\rm H_{2}O}) &= 2 \times 1.008 + 15.999 \\ &= 18.015\; \rm g\cdot mol^{-1}\end{aligned}[/tex].
The anhydrous compound would be [tex]\rm MgBr_{2}[/tex]. There was [tex]27.21\; \rm g[/tex] of this compound. Calculate the number of moles of formula units in that much of this compound:
[tex]\begin{aligned}n({\rm MgBr_{2}}) &= \frac{m({\rm MgBr_{2}})}{M({\rm MgBr_{2}})} \\ &= \frac{27.21\; \rm g}{184.113\; \rm g \cdot mol^{-1}} \\ &\approx 0.1478\; \rm mol\end{aligned}[/tex].
During heating, [tex]43.19\; \rm g - 27.21\; \rm g = 15.98\; \rm g[/tex] of water [tex]\rm H_{2}O[/tex] escaped from the hydrate. Calculate the number of formula units in that [tex]15.98\; \rm g[/tex] of [tex]\rm H_{2}O\![/tex]:
[tex]\begin{aligned}n({\rm H_{2}O}) &= \frac{m({\rm H_{2}O})}{M({\rm H_{2}O})} \\ &=\frac{43.19\; \rm g - 27.21\; \rm g}{18.015\; \rm g \cdot mol^{-1}} \\&= \frac{15.98\; \rm g}{18.015\; \rm g \cdot mol^{-1}} \\ &\approx 0.887\; \rm mol\end{aligned}[/tex].
In other words, approximately [tex]0.1478\; \rm mol[/tex] of [tex]\rm MgBr_{2}[/tex] formula units (and hence the same number of moles of [tex]{\rm MgBr_2} \cdot x\, {\rm H_2O}[/tex] formula units) contain approximately [tex]0.887\; \rm mol[/tex] of [tex]\rm H_{2}O[/tex] formula units. Calculate the ratio between the two:
[tex]\begin{aligned}x &= \frac{n({\rm H_{2}O})}{n({\rm MgBr_2})} \\ &\approx \frac{0.1478\; \rm mol}{0.887\; \rm mol} \approx 6\end{aligned}[/tex].
Hence, the formula of the hydrate would be [tex]\rm MgBr_2 \cdot 6\, H_2O[/tex].
Determinación de pH Expresa las siguientes concentraciones de [H+ ] en función del pH • [H+] = 0.001 M • [H+] = 0.002 M • [H+] = 2.45X10-4 M • [H+] = 5.2X10-9 M • [H+] = 0.04 M
Answer:
• pH = 3.0
• pH = 2.70
• pH = 3.61
• pH = 8.28
• pH = 1.40
Explanation:
El pH es una medida en química usada para determinar el grado de acidez o basicidad en una solución.
Se define como:
pH = -log₁₀ [H⁺]
El - logaritmo de la concentración molar de H⁺
Para las concentraciones de H⁺ dadas:
• [H+] = 0.001 M
pH = -log (0.001M) = 3
pH = 3.0
• [H+] = 0.002 M
pH = -log (0.002M)
pH = 2.70
• [H+] = 2.45X10-4 M
pH = -log (2.45X10-4 M )
pH = 3.61
• [H+] = 5.2X10-9 M
pH = -log (5.2X10-9 M)
pH = 8.28
• [H+] = 0.04 M
pH = -log (0.04M)
pH = 1.40
the first attempt to classify the elements was made by newlands true or false
Answer:
True. An English scientist by the name of John Newlands tried to classify the elements in a unique manner. He first started by arranging all the elements in a ascending order according to their atomic weights.
can someone send me something to get chemistry going ;);)
Answer:
Check out libretexts chemistry
Explanation:
It's basically an online free textbook for lots of subjects
highly recommended
Ok , whenever you wanna study chemistry , listen to music that you love. So each time you have to study chem , you will be excited bc u also wanna hear that music u love. Similarly , for every boring work you do , reward yourself for it. It helps , Im sure.
Thank you XD
URGENT PLEASE ELPP!!!Calculate the density of a piece of metal that has a mass of 2.5 × 102 kg and a volume of 4.1 × 103 m3.
Answer:
Density =mass/Volume
First of all let's find the mass
= 2.5 ×102kg
= 225kg
Then the volume
=4.1 × 103 m3
=422.3m3
225kg /422.3m3
=0.53279659
The density of a piece of metal that has a mass of 2.5 × 102 kg and a volume of 4.1 × 103 m3 will be 6.03 kg/m³ .
What do you mean by the density of a substance ?
Density is defined as the ratio of mass of the object to the volume of the object. Different substances have different densities.
The mathematical expression for density is as follows:
Density=Mass/Volume
The mass of a substance is expressed in kilograms and the volume is expressed in liter.
Thus, the unit of density is kg L⁻¹.
The density of a substance does not depend on the amount of the matter.
Thus, density is an intensive property.
To calculate the density -:
Given,
Mass= 2.5 ×102 kg=2550 kg
Volume=4.1 × 103 m³=422.3m³
Density=mass/volume
Density=2550/422.3
Density=6.03kg/m³
Hence, 6.03kg/m³ is the density of a piece of metal .
Learn more about density ,here:
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Select the items that describe a chemical property below. Choose THREE correct answers.
1:Heated iron can be hammered into a sword.
2:A handwarmer gets warm when it is opened and exposed to air.
3:Propane ignites to heat a grill.
4:Cotton is dyed red to make a dress.
5:A cylinder in an engine uses gasoline to move pistons.
6:Maple syrup is thicker than water.
Answer:
2:A handwarmer gets warm when it is opened and exposed to air.
3:Propane ignites to heat a grill.
4:Cotton is dyed red to make a dress.
Explanation:
The definition of a chemical property is when a property of characteristic of a substance that is observed during a reaction in which a chemical has been changed
P= f/a solve it for f
Answer:
Force = Pressure × Area
Explanation:
Easy, just invert the equation. Transpose the force variable over to the left of the equals sign, and transpose the pressure variable back to the right side.
Environmental scientists are unconcerned with methods to preserve natural resources.
Please select the best answer from the choices provided
T
F
Answer:
False
Explanation:
What is the PRECAUTION for an Irritant?
156. A solid metal sphere has a volume of 4.2 ft}. The mass
of the sphere is 155 lb. Find the density of the metal
sphere in grams per cubic centimeter.
Answer:
The answer is
0.59 g/cm³Explanation:
To find the density of the sphere we use the formula
[tex]Density \: = \frac{mass}{volume} [/tex]To find the density in g/cm³ first convert the mass into grams and the volume into cm³
For the mass we have
155 lb = 70306.82 g
For the volume
4.2 ft³ = 118930.76 cm³
Substitute the values into the above formula
That's
[tex]Density \: = \frac{70306.82 \: g}{118930.76 \: cm³} [/tex]We have the final answer as
Density = 0.59 g/cm³Hope this helps you
PLEASE HELP WILL GIVE BRAINLIEST!!!!
If the concentration of substance A of a reversible reaction in dynamic equilibrium increases, how will the equilibrium change?
A. It will shift to create more of substance A.
B. It will shift towards the reactants.
C. It will shift towards the products.
D. It will shift to create less of substance A.
Answer:
[tex]\boxed{It\ will\ shift\ to\ create\ less\ of\ substance\ A}[/tex]
Explanation:
If the concentration of any substance A in a dynamic equilibrium increases, The equilibrium will be shifted to its opposite side so that Substance A can be created less and the substance opposite to A can be created more so that a "dynamic equilibrium" can again be established.
What is the atomic number of neon?
Answer:
the atomic number of a neon is 10
What is the temperature of 0.5 moles of water vapor that occupies 120 dm3 and applies a pressure of 15,000 Pa to its container?
A. 433.21 K
B. 5.19 K
C. 7.52 K
D. 108.3 K
Reset Selection
Answer:
The answer is C. 7.52 K
Explanation:
hope it helps
Air is an example of a mixture because the elements and compounds that make up air retain their individual properties. T or F
Answer:
True
Explanation:
This is true because no chemical bonding or change was involved only mechanical mixing.
What u learned about the states of matter?
Answer:t
Explanation:
In everyday life, four states of matter are visible: solid, liquid, gas, and plasma.
Of course, matter also has other states, such as Bose-Einstein density and Fermion density, but these states are only observed under certain conditions.
A 1.30 L buffer solution consists of 0.107 M butanoic acid and 0.345 M sodium butanoate. Calculate the pH of the solution following the addition of 0.075 moles of NaOH . Assume that any contribution of the NaOH to the volume of the solution is negligible. The Ka of butanoic acid is 1.52×10−5 .
Answer:
The pH of the solution following the addition of 0.075 moles of NaOH is 5.7.
Explanation:
The equation of the buffer solution is the following:
C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq) (1)
The pH of the buffer solution can be found using the Henderson-Hasselbalch equation:
[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex] (2)
The NaOH added will react with butanoic acid tot produce sodium butanoate:
C₄H₇O₂H(aq) + OH⁻(aq) ⇄ C₄H₇O₂⁻(aq) + H₂O(l) (3)
[tex] n_{C_{4}H_{7}O_{2}H}_{i} = C*V = 0.107 M*1.30 L = 0.139 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.345 M*1.30 L = 0.449 moles [/tex]
[tex] n_{NaOH} = 0.075 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}H} = 0.139 moles - 0.075 moles = 0.064 moles [/tex]
[tex] n_{C_{4}H_{7}O_{2}^{-}} = 0.449 moles + 0.075 moles = 0.524 moles [/tex]
[tex]C_{C_{4}H_{7}O_{2}H} = \frac{0.064 moles}{1.30 L} = 0.049 M[/tex]
[tex] C_{C_{4}H_{7}O_{2}^{-}} = \frac{0.524 moles}{1.30 L} = 0.403 M [/tex]
Now, from equation (1) we have:
C₄H₇O₂H(aq) + H₂O(l) ⇄ C₄H₇O₂⁻(aq) + H₃O⁺(aq)
0.049 - x 0.403 + x x
[tex] Ka = \frac{[C_{4}H_{7}O_{2}^{-}][H_{3}O^{+}]}{C_{4}H_{7}O_{2}H} [/tex]
[tex]1.52 \cdot 10^{-5} = \frac{(0.403 + x)x}{0.049 - x}[/tex]
[tex]1.52 \cdot 10^{-5}*(0.049 - x) - (0.403 + x)x = 0[/tex]
By solving the above equation for x we have:
x = 1.85x10⁻⁶ = [H₃O⁺]
So, the concentration of butanoic acid and sodium butanoate is:
[tex][C_{4}H_{7}O_{2}^{-}] = 0.345 + 1.85 \cdot 10^{-6} = 0.345 M[/tex]
[tex][C_{4}H_{7}O_{2}H] = 0.049 - 1.85 \cdot 10^{-6} = 0.049 M[/tex]
Finally, from equation (2) we have:
[tex] pH = pKa + log(\frac{[NaC_{4}H_{7}O_{2}]}{[C_{4}H_{8}O_{2}]}) [/tex]
[tex]pH = -log(1.52 \cdot 10^{-5}) + log(\frac{0.345}{0.049}) = 5.7[/tex]
Therefore, the pH of the solution following the addition of 0.075 moles of NaOH is 5.7.
I hope it helps you!
According to the table, a 23-30 watt CFL provides __________ lumens and is equivalent to a ________ incandescent bulb.
Answer:
The correct options are;
1. 1,600
2. 100 Watts
A 23-30 watt CFL provides 1,600 lumens and is equivalent to a 100 Watts incandescent bulb
Explanation:
Brightness is measured in lumens and watts measure energy usage therefore with the use of an energy saving light bulb, the same lumination can be obtained at a lower energy usage.
According to a comparison chart for LED Lights vs. Incandescent Light Bulbs vs. Compact Fluorescents (CFLs) from USAI lightening website 23-30 watts CFL has a light output of 1,600 and is therefore produces enough light as a 100 Watts Incandescent Light Bulb
Also according to energy.gov website, CFLs save up to 75% energy such that a 23-30 watt CFL can produce the same illumination as a 100 watt incandescent bulb
Therefore we have, a 23-30 watt CFL provides 1,600 lumens and is equivalent to a 100 Watts incandescent bulb.
Answer:
1600 lumens, 100 watt incandescent
Explanation:
100% on edge (:
In the molecule 4H2O2 the number of hydrogen atoms is what
Answer:
Scientists
Explanation:
Scientists because they are the one who makes hypothesis.
45. The following data was collected for 3 compounds:
Mass of Nitrogen that combines with 1 g of Oxygen
Compound A 1.750 g
Compound B 0.8750 g
Compound C 0.4375 g
Show whether these are the same or different compounds. What chemical law is being observed here?
Answer:
The three compounds are different compounds
Explanation:
The mass of Nitrogen that combines with 1 gram of Oxygen in Compound A = 1.750 g
The mass of Nitrogen that combines with 1 gram of Oxygen in Compound B = 0.8750 g
The mass of Nitrogen that combines with 1 gram of Oxygen in Compound C = 0.4375 g
According to the law of multiple proportions, when atoms of two different elements react to form compounds, the masses of one of the elements that combines with a fixed mass of the other element are in small whole number ratios.
The ratio of the masses are;
Mass of Nitrogen in Compound B/(Mass of Nitrogen in Compound C = 0.8750/0.4375 = 2
Mass of Nitrogen in Compound A/(Mass of Nitrogen in Compound C = 1.750/0.4375= 4
Mass of Nitrogen in Compound A/(Mass of Nitrogen in Compound B = 1.750/0.8750= 2
Given that the masses of Nitrogen in the three compounds are in small whole number ratios, the three compounds, Compound A, Compound B, and Compound C are different compounds.
Need help :)….please
Answer:
i think B is correct
Explanation:
what is organic chemistry
Answer:
Organic chemistry
Explanation:
Organic chemistry is part of the chemistry that studies carbon compounds, which also use organic compounds, which have characteristics.
SOMEONE PLEASE HELP HURRY
I think the answer is A. I know it's Planet X.
A star is estimated to have a mass of 2.0 x 10 ^36kg. Assuming it to be a sphere of average radius of 7.0 x 10 ^5 km. Calculate the average density of the star in g/cm^3 and in lb/ft^3
Answer:
a) 1.392 x 10^6 g/cm^3
b) 8.69 x 10^7 lb/ft^3
Explanation:
mass of the star m = 2.0 x 10^36 kg
radius of the star (assumed to be spherical) r = 7.0 x 10^5 km = 7.0 x 10^8 m
The density of substance ρ = mass/volume
The volume of the star = volume of a sphere = [tex]\frac{4}{3}\pi r^{3}[/tex]
==> V = [tex]\frac{4}{3}*3.142*(7.0*10^8)^{3}[/tex] = 1.437 x 10^27 m^3
density of the star ρ = (2.0 x 10^36)/(1.437 x 10^27) = 1.392 x 10^9 kg/m^3
in g/cm^3 = (1.392 x 10^9)/1000 = 1.392 x 10^6 g/cm^3
in lb/ft^3 = (1.392 x 10^9)/16.018 = 8.69 x 10^7 lb/ft^3
A chemical equation is balanced when Group of answer choices the number of atoms of each element is the same in reactants and products. the charge on each atom is the same in reactants and products. the sum of the coefficients of the reactants is equal to the sum of the coefficients of the products. the total number of ions is the same in reactants and products. the total number of molecules is the same in reactants and products.
Answer:
a
Explanation:
A chemical equation is said to balanced only when the number of atoms of each element is the same in both reactants and products side. Rest all options are absurd. Hence, option a is correct.
Balancing of the reaction has no relation with coefficient, molecules or charge of the elements
which statement best describes a mole? it is 12 units of a given substance. it contains 6.02 1023 grams of sodium chloride. it is the mass of 12 carbon atoms. it contains 6.02 1023 particles of a given substance.
Answer:
The correct option is;
It contains 6.02 × 10²³ particles of a given substance
Explanation:
A mole of substance is the standard scientific unit of measurement for the quantity of the substance which is made up of a large number of small particles such as molecules, ions, atoms, electrons or other entities.
The General Conference on Weights and Measures defines the mole as the amount of a substance that contains 6.02214076 × 10²³ units of entities
The number 6.02214076 × 10²³, is also known as Avogadro's number.
The statement which correctly describes the mole is; it contains 6.02 × 10^23 particles of a given substance.
The mole refers to the amount of substance that contains the same number of elementary entities as 12 g of carbon - 12. According to Avogadro's law, the number of elementary entities in a substance is 6.02 × 10^23. These elementary entities could be atoms, ions, molecules etc.
Therefore, the statement which correctly describes the mole is; it contains 6.02 × 10^23 particles of a given substance.
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Doing my summer school work right now. Please help me pass I don’t want to take chemistry for the third time.
Answer:
13.B 0.15 M KBr
14.C 1 M C²h⁵OH
15.D 0.1 M C⁶H¹²o⁶
16.A 2 K² SO⁴
17.A 2 M K² SO⁴
18.D 0.028 M KBr
19.A 1 M Nal
20.B 0.1 M AICI³
help me please I will mark as brainliest for the first correct answer
Answer:
1. 3-methylpentane
2. 2-bromo-3-chloropentane
3. 2,2,4-trimethylpentane
Explanation:
1. CH3CH2CH(CH3)CH2CH3.
Methyl group is in the third carbon atom in the long chain. The organic compound has five(5) carbon atoms thus it is named as pentane.
Therefore the name of the compound is
3-methylpentane
2. CH3CH(Br)CH(Cl)CH2CH3
The compound has Chlorine and Bromine in the carbon chain. Chlorine is given as chloro-, Bromine is given as bromo, depending on the position in the carbon chain. Bromine is located in 2 carbon atom and chlorine is in third(3) carbon atom in the long chain. The long chain has five carbon atoms thus pentane.
Naming of the compound we begin with the on lowest in the alphabet. The name of the organic compound is therefore;
2-bromo-3-chloropentane
3. CH3CH(CH3)3CH(CH3)CH2CH3
In this long chained organic compound, methyl-group is found in 2,2 and 4th positions. Since this is still pentane, naming the organic compounds, we start with the one with the lowest carbon. Therefore this becomes;
2,2,4-trimethylpentane
I hope this helps you to know how to name the organic compounds.
Identify an element as a metal or a non-metal according to its position in the Periodic
Table
Answer:
Metals on the left of the Periodic Table.
Non-Metals on the top-right, plus Hydrogen.
b. What chemist finds
out how much nitrogen is in a sample of air
Chemical change example
Answer: burning paper
Explanation:
The paper burns in air to form smoke and ash. which makes it a chemical change.
Which statement about Schrödinger’s theory of the atomic model is true?
Answer:
it explain odds of finding the position of an electron.