0.20 g of sodium hydroxide (NaOH) pellets are dissolved in water to make 4.5 L of solution. What is the pH of this solution?

A 28.5 gram piece of iron is added to a graduated cylinder containing 45.5 mL of water. The water in the cylinder rises to the 4

yan [13]

7.91 g/ml is the density of the iron piece of 28.5 gms.

Explanation:

The density of a substance is defined as the volume it occupies. It tells the matter present in a substance.

The density is mass per unit volume and is denoted by p.

The formula for density is given by:

density (p) = $\frac{mass}{volume}$

Data given is :

mass= 28.5 grams

V1 = 45.5 ml

V2= 49.1 ml

The initial volume of water was 45.5 ml, when iron piece of 28.5 grams was added the final volume was 49.1 ml.

Putting the values in the equation of density

p = $\frac{28.5}{49.1-45.5}$

p = 7.91 g/ml

Since iron is a dense material it will occupy less volume

4 0

3 years ago

Explain the composition of dna nucleotides and the structure of the dna molecule need help

Kaylis [27]

A nucleotide is composed of a phosphate group, sugar, and nitrogen base. DNA is made of 2 strands of nucleotides linked together by covalent bonds between the phosphate and sugar of each nucleotide. The strands of nucleotides are linked together by hydrogen bonds creating DNA. Hope this helps and sorry if I made a mistake.

4 0

4 years ago

Translation: Explain the importance of energy levels,

tigry1 [53]

Answer: Formation of a stable Duplet or Octet structure

Explanation:

Energy levels refers to the definite amount of energies that electrons can have when occupying specific orbitals.

Examples are:

Level 1 as in 1s

Level 2 as in 2s, 2p

Level 3 as in 3s 3p 3d

Level 4 as in 4s 4p 4d 4f

Level 5 as in 5s .......

Level 6 as in 6s .........

Electrons can be excited to higher energy levels by absorbing energy from the surroundings during chemical reactions and so forming chemical bonds like ionic, covalent etc.

A perfect example is Sodium (Na) and Chlorine (Cl) in Sodium chloride (NaCl)

Sodium has atomic number of 11, so energy level is 1s2, 2s2 2p6, 3s1

Chlorine has atomic number of 17, so energy level is 1s2, 2s2 2p6, 3s2 3p5

You will notice that the both Na and Cl, has electrons in the energy level 3. Then, the bond formed must be one that lead to the formation of a OCTET structure: as in Na gives off its 3s1 electron TO Cl.

Thus, Cl now becomes 1s2, 2s2 2p6, 3s2 3p6 - an OCTET STRUCTURE (with completely filled outershell and full energy level 3) in NACl.

So, a duplet or Octet structure is the answer

8 0

4 years ago

(b)

Luda [366]

The maximum mass of anhydrous zinc chloride that could be obtained from the products of the reaction is 8.18 g

<h3>Stoichiometry </h3>

From the question, we are to determine the maximum mass of anhydrous zinc chloride that could be obtained

From the given balanced chemical equation,

ZnO + 2HCl → ZnCl₂ + H₂O

This means 1 mole of ZnO will completely react with 2 moles of HCl to produce 1 mole of ZnCl₂ and 1 mole of H₂O

From the given information

Number of moles of ZnO = 0.0830 mole

Now, we will calculate the number of moles of HCl that is present

Volume of HCl added = 100 cm³ = 0.1 dm³

Concentration of the HCl = 1.20 mol/dm³

Using the formula,

Number of moles = Concentration × Volume

Number of moles of HCl present = 1.20 × 0.1 = 0.120 mole

Since

1 mole of ZnO will completely react with 2 moles of HCl to produce 1 mole of ZnCl₂

Then,

0.06 mole of ZnO will react with the 0.120 mole of HCl to produce 0.06 mole of ZnCl₂

Therefore, maximum number of moles of anhydrous zinc chloride that could be produced is 0.06 mole

Now, for the maximum mass that could be produced

Using the formula,

Mass = Number of moles × Molar mass

Molar mass of ZnCl₂ = 136.286 g/mol

Then,

Mass = 0.06 × 136.286

Mass = 8.17716 g

Mass ≅ 8.18 g

Hence, the maximum mass of anhydrous zinc chloride that could be obtained from the products of the reaction is 8.18 g

Learn more on Stoichiometry here: brainly.com/question/11910892

3 0

2 years ago

My car is 10.4 feet long. how many inches is that

In-s [12.5K]

Answer:

124.8 inches

Explanation:

7 0

3 years ago

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