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16 days ago

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A different student is given a 10.0g sample labeled CaBr2 that may contain an inert (nonreacting) impurity. Identify a quantity

from the results of laboratory analysis that the student could use to determine whether the sample was pure.

1 answer:

lions [1K]16 days ago

5 0

Answer:

Explanation:

The relevant property is density.

I hope this helps! :)

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1. Bailey wants to find out which frozen solid melts the fastest: soda, gatorade, or orange juice. She pours each of the three l

VMariaS [1037]

First scenario:

IV: soda, gatorade, orange juice, and water

DV: state of the liquids listed above

Control: freezer and ice tray

Second scenario:

IV: laundry detergent, water

DV: cleanliness of the squares post-wash

Control: chocolate, cloth type, cloth squares

Third scenario:

IV: type of water used, pea plant

DV: growth of the pea plant

Control: pots and daily water amount for the plant

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10 days ago

Read 2 more answers

Find the age ttt of a sample, if the total mass of carbon in the sample is mcmcm_c, the activity of the sample is AAA, the curre

castortr0y [927]

Answer:

Explanation:

In a desert cave, an artifact has been discovered. The anthropologists investigating this artifact want to determine its age. They note that the current activity level of the artifact is 9.25 decays/s, and the carbon mass present is 0.100 kg. To ascertain the artifact's age, they will employ specific constants:

r=1.2

The formula for carbon 14 activity is

$A=A_0e^{\lambda t}$

where,

$A_0$ is the initial activity of the substance

Now, solve for t

$-\lambda t=In\frac{A}{A_0}$

$t=-\frac{1}{\lambda} In(\frac{A}{A_0} )$

$=-\frac{1}{\lambda} In(\frac{A}{\lambda r(\frac{m_c}{m_a} )} )$

since,

$A_0=\lambda r(\frac{m_c}{m_a} )$

$=-\frac{1}{\lambda} In(\frac{A\ m_a}{\lambda r m_c} )$

Thus, the age of the artifact is

$=-\frac{1}{\lambda} In(\frac{A\ m_a}{\lambda r m_c} )$

$=-\frac{1}{1.21\times 10^{-4}} In(\frac{(9.25)(2.32\times 10^{-26}}{1.21\times 10^{-4}(\frac{1}{3.15569\times10^7} )(1.2\times 10^{-12})(0.100)}} )\\\\=6303.4 \ years$

to two significant figures = 6300 years

4 0

6 days ago

Calculate the number of grams of carbon dioxide produced from complete combustion of one liter of octane by placing the conversi

Tems11 [854]

Answer:

15.71g

Explanation:

The combustion equation that applies to hydrocarbons is

CxHy + (x+y/4) O2 = xCO2 + (y/2) H2O

In the case of octane, C8H18:

C8H18 + ( 8 + 18/4 ) O2 = 8CO2 + 9H2O

C8H18 + 50/4 O2 = 8CO2 + 9H2O

C8H18 + 25/2 O2 = 8CO2 + 9H2O

2C8H18 + 25 O2 = 16 CO2 + 18H2O (this is the balanced equation)

From this balanced reaction,

2 x 22.4 L of octane generates 16 [ 12 + (16 x 2)] of carbon dioxide

That means,

44.8 L of octane generates 704g of carbon dioxide

Thus, for 1L of octane, it produces 1 L x 704g/44.8 L = 15.71g of carbon dioxide

Consequently, 15.71g of carbon dioxide is produced from the complete combustion of 1 L of octane.

7 0

16 hours ago

Write the balanced molecular and net ionic equation for the reaction that occurs when the contents of the two beakers are added

alisha [964]

1) reacting hydrochloric acid with nickel:

Balanced molecular equation: Ni(s) + 2HCl(aq) → NiCl₂(aq) + H₂(g).

Ionic equation: Ni(s) + 2H⁺(aq) + 2Cl⁻(aq) → Ni²⁺(aq) + 2Cl⁻(aq) + H₂(g).

Net ionic equation: Ni(s) + 2H⁺(aq) → Ni²⁺(aq) + H₂(g).

In this reaction, nickel undergoes oxidation, changing from an oxidation state of 0 to +2, while hydrogen is reduced from +1 to 0 (H₂).

2) reacting sulfuric acid with iron:

Balanced molecular equation: Fe(s) + H₂SO₄(aq) → FeSO₄(aq) + H₂(g).

Ionic equation: Fe(s) + 2H⁺(aq) + SO₄²⁻(aq) → Fe²⁺(aq) + SO₄²⁻(aq) + H₂(g).

Net ionic equation: Fe(s) + 2H⁺(aq) → Fe²⁺(aq) + H₂(g).

In this scenario, iron is oxidized from an oxidation state of 0 to +2, while hydrogen experiences reduction from +1 to 0 (H₂).

3) hydrobromic acid reacting with magnesium:

Balanced molecular equation: Mg(s) + 2HBr(aq) → MgBr₂(aq) + H₂(g).

Ionic equation: Mg(s) + 2H⁺(aq) + 2Br⁻(aq) → Mg²⁺(aq) + 2Br⁻(aq) + H₂(g).

Net ionic equation: Mg(s) + 2H⁺(aq) → Mg²⁺(aq) + H₂(g).

This reaction sees magnesium oxidized from 0 to +2, and hydrogen reduced from +1 to 0 (H₂).

4) acetic acid reacting with zinc:

Balanced molecular equation: Zn(s) + 2CH₃COOH(aq) → (CH₃COO)₂Zn(aq) + H₂(g).

Ionic equation: Zn(s) + 2H⁺(aq) + 2CH₃COO⁻(aq) → Zn²⁺(aq) + 2CH₃COO⁻(aq) + H₂(g).

Net ionic equation: Zn(s) + 2H⁺(aq) → Zn²⁺(aq) + H₂(g).

Here, zinc gets oxidized from 0 to +2 (Zn²⁺), while hydrogen is reduced from +1 to 0 (H₂).

7 0

5 days ago

So, could you use easily use chromic acid to visualize spots when you are monitoring a reaction to make a ketone out of an alcoh

VMariaS [1037]

While the original inquiry is incomplete, the comprehensive question is:

Many chemicals can illustrate spots on a TLC plate that have been processed and dried. The permanganate used in the video creates yellow spots against a purplish background, taking advantage of the oxidizing capability of basic permanganate (MnO4), which outperforms chromic acid as an oxidizing agent. Chromic acid can also be employed to visualize spots, resulting in a green hue on the yellow background, indicating oxidation. So, can chromic acid be conveniently used to visualize spots when tracking a reaction converting an alcohol into a ketone? What observations are anticipated if one attempts this? Furthermore, if a small amount of alcohol is included in a solvent mixture for eluting your TLC plate, why must the plate be fully dried before visualizing the spots with an oxidizing agent like permanganate or chromic acid?

Answer:

Typically, using chromic acid to visualize spots during the conversion of alcohol to ketone is not feasible. The alcohol (substrate) will convert into its respective ketone due to the presence of chromic acid, causing the spots for the product and the reactant to align horizontally. This alignment complicates differentiation between the spots, making chromic acid unsuitable for this purpose.

It's vital to ensure that the plate is completely dry before observing spots with an oxidizing agent, even if alcohol is present in the solvent mixture. Incomplete drying could lead to oxidation of the alcohol by the oxidizing agent, resulting in transformation to carboxylic acid or ketone, thereby creating a new spot.

6 0

13 days ago