Cellular respiration is? (Single choice.)
A. a chemical reaction that converts energy from food molecules by way of oxygen into a usable energy called ATP.
B. a chemical reaction that converts carbon dioxide and water into glucose and oxygen.
C. a chemical reaction that converts that occurs only in animals.
D. a chemical reaction that occurs only in plants.

Answer:

B) What is the weight of the sample?

Explanation:

The least useful question for the student to identify the sample is "What is the weight of the sample?"

To identify a sample, it is important to know its solubility (homogenous or heterogenous), chemical properties such as melting and boiling point, and whether sample is attracted towards the magnet or not to know the nature of the sample.

Weights is the least useful characteristic of a sample that can help to identify the sample.

Hence, the correct answer is "B) What is the weight of the sample?".

Answer:

1. Volume of box is 314500 cm³.

2. Volume of box 126900 cm³.

3. Mass of sample is 6.309 g.

4. Density of aluminum is 2.7 g/mL.

5. Volume of sample is 31.9 mL.

Explanation:

1. Determination of the volume of the box

Length (L) = 125 cm

Width (W) = 37 cm

Height (H) = 68 cm

Volume (V) =?

V = L × W × H

V = 125 × 37 × 68

V = 314500 cm³

2. Determination of the volume of the box

Length (L) = 423 cm

Width (W) = 12 cm

Height (H) = 25 cm

Volume (V) =?

V = L × W × H

V = 423 × 12 × 25

V = 126900 cm³

3. Determination of the mass of the sample.

Mass of weigh boat = 1.326 g

Mass of weigh boat + Sample = 7.635 g Mass of the sample =?

Mass of Sample = (Mass of weigh boat + Sample) – (Mass of weigh boat)

Mass of Sample = 7.635 – 1.326

Mass of Sample = 6.309 g

4. Determination of the density of aluminum.

Volume of water = 10 mL

Mass of aluminum = 14.74 g

Volume of water + aluminum = 15.46 mL

Density of aluminum =?

Next, we shall determine the volume of aluminum. This can be obtained as follow:

Volume of water = 10 mL

Volume of water + aluminum = 15.46 mL

Volume of aluminum =?

Volume of aluminum = (Volume of water + aluminum) – (Volume of water)

Volume of aluminum = 15.46 – 10

Volume of aluminum = 5.46 mL

Finally, we shall determine the density of aluminum. This can be obtained as follow:

Mass of aluminum = 14.74 g

Volume of aluminum = 5.46 mL

Density of aluminum =?

Density = mass / volume

Density of aluminum = 14.74 / 5.46

Density of aluminum = 2.7 g/mL

5. Determination of the volume of sample.

Mass of sample = 24.5 g

Density of sample = 0.768 g/mL.

Volume of sample =?

Density = mass / volume

0.768 = 24.5 / volume of sample

Cross multiply

0.768 × Volume of sample = 24.5

Divide both side by 0.768

Volume of sample = 24.5 / 0.768

Volume of sample = 31.9 mL.

This question is incomplete, the complete question is;

The weight loss of an aluminum alloy corroding in a solution of hydrochloric acid was observed to be 0.250 g/cm² after an 8 h immersion period [13]. What is the corresponding anodic current density in milliamperes per square centimeter, assuming that all the corrosion is due to the following anodic half-cell reaction:

Al → Al³⁺ + 3e⁻

The atomic weight is 58.7 g/mol

Answer:

Current density in milliamperes per square centimeter is 45.81 mA/cm²

Explanation:

Given the data in the question;

we know that Faradays law of electrolysis states that;

amount of substance produced at each electrode is directly proportional to the quantity of charge flowing through the cell.

so

m = ( Q/F) (M/z)

where m is the mass of substance liberated at an electrode( 0.250 g/cm²)

Q is the total electric charge passed through the substance

F is Faradays constant (96,500 C/mol)

M is the molar mass of the substance( 58.7 g/mol )  and Z is the number of electrons transferred(3)

Also

we know that; Q = It

where I is current and t is time( 8hrs × 60 × 60 = 28800 sec )

we substitute  Q = It  into our equation'

we have;

m = ( It/F) (M/z)

m = ItM / Fz

mFz = ItM

I = mFz / tM

so we substitute

I = [0.250 g/cm² × 96,500 C/mol × 3] / [ 28800 × 58.7 g/mol]

I = 72375 /  1690560

I = 0.04581 A/cm²

we know that; 1 ampere = 1000 milliampere

so

I = 0.04581 × 1000

I = 45.81 mA/cm²

Therefore, current density in milliamperes per square centimeter is 45.81 mA/cm²

Answer:

Decreases

Explanation:

Answer:

See explanation

Explanation:

Mass of mixture of  fluorene and benzoic acid = 558 mg

Mass of pure fluorene  after purification = 185 mg of fluorene

Mass of pure  benzoic acid after purification = 144 mg of benzoic acid

Percentage of fluorene int he mixture = 185mg/558mg * 100 = 33.15 %

Percentage of benzoic acid in the mixture = 144mg/558mg * 100 = 25.81 %

Percentage of impurities = 100% - [33.15 + 25.81]

Percentage of impurities = 100 - 58.96

Percentage of impurities = 41.04 %

Answer:

Clouds

Explanation:

Because I just got it right

Answer:neutral

Explanation:ionic compounds is between a cation and anion so they cancel eachother out

Answer:

D =  42.6 g

Explanation:

Given data:

Mass of oxygen needed = ?

Mass of phosphorus react = 33 g

Solution:

Chemical equation:

4P + 5O₂     →      2P₂O₅

Number of moles of phosphorus:

Number of moles = mass/molar mass

Number of moles = 33 g/ 30.97 g/mol

Number of moles = 1.065 mol

now we will compare the moles of P and oxygen.

                P         :       O₂

                4         :        5

          1.065        :        5/4×1.065 = 1.33mol

Mass of oxygen needed:

Mass = number of moles × molar mass

Mass = 1.33 mol × 32 g/mol

Mass = 42.6 g