Explanation:
Gold (AU)................
Chromium is manufactured by heating a mixture of chromium(III) oxide with aluminium powder.
Cr2O3(s) + 2Al(s) → 2Cr(s) + Al2O3(s)
a=Calculate the mass of aluminium needed to react with 50 g of Cr2O3.
b=Calculate the mass of chromium produced from 50 g of Cr2O3.
c=Calculate the mass of chromium produced from 5 kg of Cr2O3.
d=Calculate the mass of chromium produced from5 tonnes of Cr2O3.
Note: 1 tonne = 1,000,000 g
Ar: Cr = 52, O = 16, Al = 27
PLEASE HELP!!
A scientist places a pH meter in a sample of concentrated potassium hydroxide (KOH). The scientist slowly adds nitric acid (HNO3) to the KOH and monitors the pH. Describe how the pH and hydronium ion concentration will change in the solution as the acid is added.
Answer:
pH of the solution will decrease & hydronium ion concentration will increase in the solution as the acid is added.
Explanation:
Help this is for marks, who ever answers get brainliest
Answer:
Coal
Explanation:
thx for points :D
Answer:
Coal
Explanation:
your welcome<3
If 220 mL of a 12.0 M HCl solution is diluted to 1000 mL, what will be the concentration of the new solution?
Answer:
2.64 M
Explanation:
Use the dilution equation M1V1 = M2V2, where:
M1 = 12.0 M HCl
V1 = 220 mL HCl
M2 = ?
V2 = 1000 mL HCl
(12.0 M HCl)(220 mL HCl) = M2(1000 mL HCl)
M2 = 2.64 M HCl
Calculate the Rf value of compounds X and Y based on information (X travels 0.5.0 cm, Y travels 1.0 cm from the origin line; the solvent front is 3.0 cm). Comment on the polarity and separation of X and Y on the TLC plate.
Answer:
Retention factor or [tex]R_f[/tex] value is defined as the ratio of distance traveled by the unknown to the distance traveled by the solvent front.
[tex]R_f=\frac{\text{ distance by unknown}}{\text {distance by solvent}}[/tex]
Putting in the values we get:
[tex]R_f_{X}=\frac{0.50cm}{3.0cm}=0.16[/tex]
[tex]R_f_{Y}=\frac{1.0cm}{3.0cm}=0.33[/tex]
As the [tex]R_f[/tex] value of Y is more than X , it follows that Y compound will be retained less strongly than the compound X. Thus Y is more polar than X.
Unit 4.2 quiz chemistry
Answer:
H₂SO₄ is the correct answer sorry im late
Help bestie pls help ASAP thank you
Explanation:
heyyyyyyyyy how are you sure
Four students are gathering information on elements to determine their identity.
Student 1 counts both neutrons and electrons.
Student 2 counts the number of neutrons.
Student 3 counts the number of valence electrons.
Student 4 counts the number of protons.
Which of the following students will correctly identify the element based on their
data?
Answer:
Student 4
Explanation:
In the structure of the atom of an element, there are protons, electrons and neutrons. The number of protons in the atom of such element determines the atomic number of the element. For example, if Calcium contains 20 protons, the atomic no of Calcium will be 20. Since this is so, it means that the identity of an element on the periodic table can be known using the number of protons/atomic no.
According to this question, four students are gathering information on elements to determine their identity. Based on the explanation above, it takes only the number of protons = atomic no. of the element to identify it. Hence, student 4, who counts the number of protons will correctly identify the element using his/her data.
In the reaction 2 H, Ł02 → 2 H, O, what is the mole ratio of hydrogen to water?
A 2:2
B 2:1
C 1:2
D 4:4
A
because both have 2's in front of them
Use the following balanced reaction to solve:
P4 (s) + 6H2 (g) → 4PH3 (g)
How many grams of phosphorus trihydride will be formed by reacting 60 L of Hydrogen gas with an excess of P4?
Answer: 60.7 g of [tex]PH_3[/tex] will be formed.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given volume}}{\text{Molar volume}}[/tex]
[tex]\text{Moles of} H_2=\frac{60L}{22.4L}=2.68moles[/tex]
The balanced chemical reaction is
[tex]P_4(s)+6H_2(g)\rightarrow 4PH_3(g)[/tex]
[tex]H_2[/tex] is the limiting reagent as it limits the formation of product and [tex]P_4[/tex] is the excess reagent.
According to stoichiometry :
6 moles of [tex]H_2[/tex] produce = 4 moles of [tex]PH_3[/tex]
Thus 2.68 moles of [tex]H_2[/tex] will produce=[tex]\frac{4}{6}\times 2.68=1.79moles[/tex] of [tex]PH_3[/tex]
Mass of [tex]PH_3=moles\times {\text {Molar mass}}=1.79moles\times 33.9g/mol=60.7g[/tex]
Thus 60.7 g of [tex]PH_3[/tex] will be formed by reactiong 60 L of hydrogen gas with an excess of [tex]P_4[/tex]
How can you determine if elements have the same properties?
Answer:
You will know if elements have the same properties if they are in the same column (up and down) on the periodic table.
Explanation:
Ex: Lithium and a hydrogren has the same properites bcause they are both on the same line/column. Columns are up and down the table and rows are left and right. Hope this helps
Potassium chlorate, a common oxidizing agent in fireworks and matchheads, undergoes a solid-state disproportionation reaction when heated:
4KClO3 (s) ⟶ Δ3KClO4 (s) + KCl (s).
Use ΔHf ° and S° values to calculate ΔG_sys ° (which is ΔGrxn °) in kJ at 25°C for this reaction.
Answer:
Explanation:
[tex]\text{From the information given:}[/tex]
[tex]\text{The chemical reaction is : } 4 KClO_{3(s)} \to 3 KClO_{4(s)} + KCl_{(s)}[/tex]
[tex]\text{To find} \ \Delta G^0_{rxn}\ \text{using the formula}: \\ \\ \Delta G^0_{rxn} = \sum n_p \times \Delta _f G^0 (Products) - \sum n_R \times \Delta _fG^0 ( Reactants) \\ \\ where; n_p = \text{no of moles of products } \ and; \\ \\ n_R = \text{no of moles of reactants }[/tex]
[tex]\implies G^0_{rxn} = 3 \times \Delta _fG^0 [KClO_4{(s)}] + \Delta_fG^0[KCl_{(s)}] - 4 \times \Delta _f G^0 [ KClO_3 (s) ][/tex]
[tex]\Delta _fG^0 \ values \ at \ 25^0 \ C (298 \ K) are\ given \ as:\\\\ \Delta _fG^0 [KClO_4(s)] = -303.09 \ kJ \\ \\ \Delta _fG^0 [KCl(s) ] = - 409.14 \ kJ \\ \\ \Delta_f G^0 [KClO_3_{(s)}] = -296.25 \ kJ \\ \\ replacing \ the \ above \ values \ into \ equation (1) ; then:\\ \\ \\\Delta G^0_{rxn} = 3 *(-303.09) + (-409.14) - 4*(-296.25) \ kJ \\ \\ = (-909.27 - 409.14 + 1185) \ kJ \\ \\ = -133.41 \ kJ \\ \\ \mathbf{\Delta G^0_{rxn} = -133.4 \ kJ }[/tex]
The standard free energy change of the reaction is -133 kJ.
From the reaction equation, we have; 4KClO3 ⇄ 3KClO4 (s) + KCl (s). The standard free energy of formation of each specie is given below;
ΔG°f KClO3 = -296.35 kJ
ΔG°f KClO4 = -303.09 kJ
ΔG°f KCl = -409.14 kJ
Hence;
ΔG°rxn = [3(-303.09)] + ( -409.14)] - [(4( -296.35))]
ΔG°rxn = (-909.27) + (-409.14) - (-1185.4)
ΔG°rxn = -133 kJ
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Unit 4.2 quiz chemistry
A student places 2 mL of 2% ethanolic silver nitrate solution into test tube. They add 2 drops of an unknown compound into the test tube while gently mixing. After five minutes, the student heated the test tube in a water bath and a white precipitate formed. They added 2 drops of 1 M nitric acid to the mixture which was cooled to room temperature and still noticed the precipitate did not dissolve in response to the nitric acid. What compound is most likely the unknown
Answer:
hi
Explanation:
i am smart but i need this app cuz some are realy hard
1/5 divided by 3/4 fraction
Answer:
4/15
Explanation:
we can write out an equation by doing (1/5 ÷ 3/4) and then switch the sign to multiplication and we can keep the first fraction the same (in this case 1/5) and then we flip the second fraction BUT when we flip the second fraction upside-down we have to change the symbol to multiplication (1/5x4/3)
then after that all we do is multiply the denominators and numerators :)
1 x 4 = 4
_______
5 x 3 = 15
answer would be 4/15
In order to determine the answer to a chemistry problem, a student first converted the given percentages to mole by assuming the sample size was 100 grams. Then the student divide by the smallest mole amount of the elements present. Finally the student used the ratios to write a formula. Which of the following best describes the problem the student likely solved?
a. Determined percent composition
b. None of the above
c. Determining molecular formula
d. Determining empirical formula
Answer: d. Determining empirical formula
Explanation:
Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.
Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.
Step 1: If percentage are given then we are taking total mass is 100 grams. So, the mass of each element is equal to the percentage given.
Step 2 : convert given masses into moles
Step 3 : For the mole ratio, divide each value of moles by the smallest number of moles calculated
Step 4: The mole ratio gives the empirical formula of the compund.
The correct value of m, n, x and y to obtain a balanced equation is?
m B2O3(s) + n HF(l) → x BF3(g) + y H2O(l)
a.
m=1, n=1, x=1 and y=1
b.
m=1, n=6, x=2 and y=3
c.
m=1, n=1.5, x=1 and y=1
d.
m=2, n=12, x=4 and y=6
Answer:
d
Explanation:
answer d makes the equation balance
What type of solution would have a pH of 8 ?
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Answer: Weak base
Explanation:
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Answer and Explanation:
Solutions that have a pH of 8 would be considered a Weak Base.
This is because a weak base is a base that, upon dissolution in water, does not dissociate completely.
Solutions/liquids that have a pH higher than a pH of 7 are basic solutions, while solutions/liquids that have a pH lower than a pH of 7 are acidic solutions.
When the pH level is closer to 7, it is weak, and when it is far from 7, like if it is 1 or 12, then it is a strong acid/base.
#teamtrees #PAW (Plant And Water)
A liquid is placed in a closed container and time passes until
the level of the liquid is constant
The general situation described by the rate of evaporation is
equal to the rate of condensation called a:
a
state balance
b static equilibrium
chemical balance
d dynamic equilibrium
Answer: Dynamic equilibrium
Explanation:
Mass of watch glass + filter paper = 105.98 g
Mass of watch glass + filter paper + crystallized product = 109.03 g
Mass of uncrystallized product (show work) =
Mass of methyl benzoate = 3.08 g
Volume of nitric acid used = 2.0 mL
Theoretical yield based on each of the starting materials
(Please use two Dimensional Analysis (DA) equations, one for the maximum amount of product obtainable from the amount of methyl benzoate you used and the other from the concentrated nitric acid, then use the lesser of the two to determine the Limiting Reagent; you must determine the number of moles in 2.00 mL of concentrated nitric acid [concentration 69.0% (w/w), and density (1.42 g/mL)].
Required:
a. Identity of the Limiting reagent (LR) based on the above two DA equations = __________
b. Max amount of product obtainable from the LR = ___________
c. Mass of the product you obtained: ____________
Answer:
Explanation:
Mass of uncrystallized product = (Mass of watch glass + filter paper + crystallized product) - (Mass of watch glass + filter paper)
Mass of uncreystaliized product = 109.03 gm - 105.98 gm
Mass of uncrystaliized product = 3.05 gm
For methyl benzoate;
mass = 3.08 g
no of moles = 3.08 g/ 136.15 g/mol = 0.0226 mole
It is possible for the formation of 1 mole of nitro methyl benzoate from a mole of methyl benzoate.
moles of nitro methyl benzoate that can be formed from 0.0226 moles of methyl benzoate = 0.0226 moles
∴
mass of nitro methyl benzoate = 0.0226 mol × 181.15 gm /mol
mass of nitro methyl benzoate = 4.098 gm
For HNO_3 solution:
mass = 1.42 gm/ml × 2.0 ml
mass = 2.84 gm
Mass of HNO3 in 2.84 gm solution[tex](69\% w/w)= 2.84 gm * \dfrac{69}{100 }[/tex]
= 1.9596 gm
Moles of HNO3 = [tex]\dfrac{ 1.9596 \ gm }{ 63.01 gm /mol}[/tex]
= 0.0311 mole
1 mol of HNO_3 can be formed from 1 mole of nitro methyl benzoate
Thus; moles of nitro methyl benzoate that can be formed from 0.0311 mole of HNO_3 = 0.02256 mole
The mass for nitro methyl benzoate can now be determined as:
= 0.0311 mole × 181.5 gm/mole
= 5.634 gm
Since the mass formed from methyl benzoate is lesser, then methyl benzoate serves as the limiting reagent.
The mass obtainable from the LR = 4.098 gm
the ideal of stationary orbit was first given by?
Answer:
Neil Bohr
Explanation:
Thank me latur✊
PLEASE HELP:
iron reacts with nitrogen to form iron(III) nitride
Answer:
[tex]2Fe +N_{2} -> 2FeN[/tex]
Explanation:
Iron is Fe, nitrogen is N. Nitrogen is diatomic, which means it occurs as a molecular pair by itself. Iron III nitride has a chemical formula of FeN because nitrogen has a charge of 3-, and iron III tells us the iron has a charge of 3+ so you just need one of each to make the charges balance and the compound neutral.
When iron reacts with nitrogen to form iron(III) nitride, the balanced chemical equation of this reaction is as follows:
2 Fe + N₂ → 2FeN
What is balanced chemical equation ?The term balanced chemical equation is defined as a chemical equation in which mass is conserved and there are equal numbers of atoms of each element on both sides of the equation.
The chemical equation must be balanced in order to obey the law of conservation of mass. When the number of different atoms of elements in the reactants side equals the number of atoms in the products side, the chemical equation is balanced.
Nitrogen is diatomic, that means it occurs as a molecular pair by itself. Iron III nitride has a chemical formula of FeN because nitrogen has a charge of 3-, and iron III tells us the iron has a charge of 3+ .
Thus, iron reacts with nitrogen to form iron(III) nitride.
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Radiation from which type of decay has the most energy?
A. Alpha decay
B. Electromagnetic decay
C. Beta decay
D. Gamma decay
Pls answer quick
Answer: D
Explanation:
Radiation from gamma decay has the most energy and the correct option is option D.
What is Radioactive Decay?To become more stable, the nuclei undergo radioactive decay. In this process, the nuclei give off energy and may also emit charged particles of matter.
Types of radioactive decay include alpha, beta, and gamma decay. In alpha and beta decay, both particles and energy are emitted. In gamma decay, only energy, in the form of gamma rays, is emitted.
In the gamma decay, a nucleus changes from a higher energy state to a lower energy state through the emission of electromagnetic radiation.
Therefore, Radiation from gamma decay has the most energy and the correct option is option D.
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What is the other product for this reaction? Hbr + NaOH —> ( select 2)
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Answer: HBr + NaOH = nabr + h2o
Explanation:
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g You are given a 1.25 gram mixture of calcium nitrate and calcium chloride. You dissolve this mixture in 200.0 mL of water and add an excess of 0.300 M silver nitrate. You collect and dry the white precipitate which forms and find it has a mass of 0.535 grams. Calculate the percent calcium chloride by mass in the original mixture.
Answer:
16.51%
Explanation:
The reaction that takes place is
CaCl₂(aq) + 2AgNO₃(aq) → 2AgCl(s) + Ca(NO₃)₂(aq)Meaning that the white precipitate that formed is AgCl. Now we convert 0.535 g of AgCl into moles, using its molar mass:
0.535 g ÷ 143.43 g/mol = 0.00373 mol AgClThen we convert 0.00373 moles of AgCl into moles of CaCl₂, using the stoichiometric coefficients:
0.00373 mol AgCl * [tex]\frac{1molCaCl_2}{2molAgCl}[/tex] = 0.00186 mol CaCl₂We convert moles of CaCl₂ into grams, using its molar mass:
0.00186 mol CaCl₂ * 110.98 g/mol = 0.206 gFinally we calculate the percent of CaCl₂ by mass in the original mixture:
0.206 g / 1.25 g * 100% = 16.51%The percent calcium chloride by mass in the original mixture is 16.4%
The equation of the reaction between calcium nitrate and silver chloride is:
[tex]\mathbf{CaCl_2 + 2AgNO_3 \to 2 AgCl+Ca(NO_3)_2}[/tex]
Given that;
the weight mass of the white precipitate formed is = 0.535 gramsthe number of moles of the precipitated AgCl is:
= 0.535 g / 143.32 g/mol
= 0.0037 moles
From the above reaction, If 2 moles of AgCl are formed by 1 mole of CaCl2
Then, 0.0037 moles of AgCl will form (0.0037 × 1)/2 moles of CaCl2.
0.0037 moles of AgCl will form 0.00185 moles of CaCl2.
Now, we can say that the number of moles of CaCl2 present in the mixture is = 0.00185 moles
Mass amount of CaCl2 present = 0.00185 moles × 110.98 g/mol
Mass amount of CaCl2 present = 0.205 grams
Finally, the mass percentage [tex]\mathbf{=\dfrac{0.205}{1.25}\times 100\%}[/tex]
= 16.4%
Therefore, we can conclude that the percent calcium chloride by mass in the original mixture is 16.4%
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This timeline woulchre useful to someone who was writing a report titled
What is 2AI(s) + FeO3(s) = Ai2O3(s) + 2Fe(s)
Answer:
it's a double displacement Reaction.
Solid iron is mixed with a solution of copper (I) nitrate to form iron (III) nitrate solution and metal copper. (what is the equation)
Answer:
Fe + 3CuNO₃ → Fe(NO₃)₃ + 3Cu
Explanation:
Solid Iron = FeCopper (I) nitrate = CuNO₃ (Nitrate, NO₃⁻, always has a charge of -1).Iron (III) nitrate = Fe(NO₃)₃ (That way the compound has an overall neutral charge)Metal Copper = CuWriting the equation using symbols leaves us with:
Fe + CuNO₃ → Fe(NO₃)₃ + CuIt is not balanced yet. Now we balance the NO₃ species on the left side:
Fe + 3CuNO₃ → Fe(NO₃)₃ + CuFinally we balance the Cu species on the right side:
Fe + 3CuNO₃ → Fe(NO₃)₃ + 3CuWhat is the name of this molecule?
Answer:
pentanoic acid
Explanation:
it has 5 carbon atoms which gives it the parent name pent, and its attached to the ester group
If a mechanical wave has a frequency of 0.147 Hz and a wavelength of 12.05 m, what is the velocity of the wave? (round to the hundredths place)
Answer:
0.147 Hz because I took the test
The velocity of a wave is the product of its frequency and wavelength. The velocity of wave with 0.147 Hz and 12.05 m is 1.77 m/s.
What is frequency ?The frequency of a wave is the number of wave cycles per unit time. Frequency is the inverse of time period of the wave. It is inversely proportional to the wavelength. Unit of frequency is Hz which is equivalent to s⁻¹.
The wavelength of a wave is the distance between two consecutive crests or troughs. The wavelength λ, and frequency ν of a wave is related to the velocity v of the wave as follows:
v = νλ
Given that,
frequency = 0.147 Hz
wavelength = 12.05 m
then, velocity = 0.147 Hz × 12.05 m = 1.77 m/s.
Therefore, the velocity of the mechanical wave is 1.77 m/s.
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