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3 years ago

PLEASE HELP i’ll mark brainliest ( reporting fake answers)

Chemistry

1 answer:

kherson [118]3 years ago

6 0

Delta S reaction= Delta S products- Delta S reactants

don't forget to mulitiply by coefficients

also

here is a really slow way to do it

you know the moles of gas increased

so Delta S is positive

so its B or D

then just do the units digit to see which one match up

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What is the empirical formula for a compound which contains 67.1 zinc and the rest is oxygen

wolverine [178]

Answer:

The empirical formula is ZnO2

Explanation:

What is the empirical formula for a compound which contains 67.1% zinc and the rest is oxygen?

Step 1: Data given

Suppose the compound has a mass of 100.0 grams

A compound contains:

67.1 % Zinc = 67.1 grams

100 - 67.1 = 32.9 % oxygen = 32.9 grams

Molar mass of Zinc = 65.38 g/mol

Molar mass of O = 16 g/mol

Step 2: Calculate moles of Zinc

Suppose the compound is 100 grams

Moles Zn = 67. 10 grams / 65.38 g/mol

Moles Zn = 1.026 moles

Step 3: Calculate moles of O

Moles O = 32.90 grams / 16.00 g/mol

Moles O = 2.056 moles

Step 4: Calculate mol ratio

We divide by the smallest amount of moles

Zn: 1.026/1.026 = 1

O: 2.056/1.026 = 2

The empirical formula is ZnO2

To control this we can calculate the % Zinc for 1 mol

65.38 / (65.38+2*16) = 0.67.1 = 67.2 %

7 0

3 years ago

Question 3 (1 point) The extinction coefficient for copper sulfate in aqueous solution is 12 M-1.cm-1 at 800 nm. If the absorban

Troyanec [42]

Answer:

The concentration of the copper sulfate solution is 83 mM.

Explanation:

The absorbance of a copper sulfate solution can be calculated using Beer-Lambert Law:

A = ε . c . l

where

ε is the extinction coefficient of copper sulfate (ε = 12 M⁻¹.cm⁻¹)

c is its molar concentration (what we are looking for)

l is the pathlength (0.50 cm)

We can use this expression to find the molarity of this solution:

$c=\frac{A}{\epsilon.l } =\frac{0.5}{12M^{-1}cm^{-1}0.50cm } =0.083M=83mM$

3 0

3 years ago

assuming the magnesium ribbon wasn't sufficiently polished to remove a coating of magnesium oxie on the surface. how would this

Ira Lisetskai [31]

The magnesium ribbon wasn't sufficiently polished to remove a coating of magnesium oxie on the surface. how would this affect the volume of hydrogen gas produced? would this error cause the gas constant to be overestimated, underestimated, or remain unaffected?

1. Since, the magnesium ribbon wasn’t sufficiently polished to remove a coating of magnesium oxide on surface, the actual mass of magnesium taken will be less (as it also contains magnesium oxide). Hence, the number of moles of magnesium reacted and the number of moles of hydrogen produced will be less. Due to this, the volume of hydrogen gas produced will be less and the gas constant will be underestimated. R=\frac {PV}{nT} . Here n is calculated from weight of Mg taken but V is measured. Thus values of n will be same but the value of V will be lower. Hence, the value of R will be lower.

2. When droplets of water are remaining in the eudiometer tube, there volume will be added to the volume of hydrogen and the measured volume of hydrogen will be more than actual volume. Due to this, the value of the gas constant will be overestimated.

3. When small amount of hydrogen dissolves in water, the measured volume of hydrogen will be lower than the actual volume. This will underestimate the value of the gas constant.

4. When the temperature of the gas was underestimated, the value of the gas constant will be overestimated as the gas constant is inversely proportional to the temperature. {PV}

{nT}.

Magnesium is a chemical detail with the symbol Mg and atomic number 12. it is a glittery gray solid which stocks many bodily and chemical residences with the alternative 5 alkaline earth metals (institution 2 of the periodic desk).

This element is produced in huge, growing old stars from the sequential addition of three helium nuclei to a carbon nucleus. whilst such stars explode as supernovas, a lot of the magnesium is expelled into the interstellar medium wherein it may recycle into new big name structures. Magnesium is the eighth maximum abundant element inside the Earth's crust and the fourth maximum not unusual detail in the Earth (after iron, oxygen and silicon), making up 13% of the planet's mass and a big fraction of the planet's mantle. it's miles the 0.33 maximum abundant detail dissolved in seawater, after sodium and chlorine.

Learn more about Magnesium here:-brainly.com/question/25860912

#SPJ4

8 0

1 year ago

When aqueous ammonia is added to a solution containing Bi3+ and Cu2+ cations, ____________ occurs. A. Reduction to black bismuth

MissTica

Answer:

C. Precipitation of white bismuth hydroxide.

Explanation:

When aqueous ammonia is added to a solution that has Bi3+ and CU2+ cations, what we would have as a chemical result is the precipitation of white Bismuth hydroxide.

The chemical reaction for this can be written as,

Bi3+ + 2NH3 + 3H2O ⇌ Bi(OH)3(s) + 3NH4

Thank you!

6 0

3 years ago

The sp3 hybridization has what percent s character and what percent p character respectively?

Salsk061 [2.6K]

Answer:

The sp³ orbital hybridization has 25% s-character and 75% p-character.

Explanation:

Hybridization refers to the process of mixing of a given number atomic orbitals to form equal number of new hybrid orbitals. The three types of hybrid orbitals are sp³, sp² and sp.

The four sp³ hybridized orbitals are formed by the mixing of one s orbital and three p orbitals.

Thus s-character in a sp³ hybridized orbital = (1÷4)×100 = 25%

and p-character in a sp³ hybridized orbital = (3÷4)×100 = 75%

Therefore, the sp³ orbital hybridization has 25% s-character and 75% p-character.

8 0

3 years ago