How to convert 5.2 km to mm

For each pair of covalently bonded atoms, choose the one expected to have the shortest bond length. (A) C-I (B) H-I ...... (A,B)

UNO [17]

Answer:

i) B

ii) D

Explanation:

<em>Bond length is determined by the size of the atoms involved and the bond order </em>

A) C-I

B) H-I

answer : H-I has the shortest bond length because H has an electronegativity value of 2.2 while C has an electronegativity value of 2.5 hence the bond between H-I is greater than C - I due the electronegativity difference between H-I is greater as well.

C) H-Cl

D) H-I

answer : H-Cl has the shortest bond length due the electronegativity difference between H-CI is greater as well.

8 0

2 years ago

A sample of hydrogen gas has an initial pressure of 2.86 atm and an initial volume of 8472 mL If the volume of the

Oliga [24]

<h3>Answer:</h3>

Gas law : Boyle's law

New pressure: 66.24 atm

<h3>Explanation:</h3>

Concept tested: Gas laws (Boyle's law)

<u>We are given,</u>

Initial pressure, P₁ = 2.86 atm
Initial volume, V₁ = 8472 mL
New volume, V₂ IS 365.8 mL

We need to determine the new pressure, P₂

According to Boyle's law , the volume of a fixed mass of a gas and the pressure are inversely proportional at constant temperature.

That is, $P\alpha \frac{1}{V}$
This means , PV = k (constant)
Therefore; P₁V₁ = P₂V₂

Rearranging the formula, we can get the new pressure, P₂

P₂ = P₁V₁ ÷ V₂

= (2.86 atm × 8472 mL) ÷ 365.8 mL

= 66.24 atm

Therefore, the new pressure is 66.24 atm

5 0

3 years ago

Name two elements, compounds and mixtures that are essential for living organisms. Also write why are they essential?

svlad2 [7]

elements:

calcium : for strong bones

Iron : maintaining haemoglobin for metabolism

compunds

sodium chloride : to maintain blood pressure and other life processes

Adenosine Triphosphate: for metabolism, to maintain rate of inhalation and exhalation of oxygen and to supply energy

Mixture:

I) gasoline : used as fuel

ii) cement : used in construction

5 0

3 years ago

Read 2 more answers

The question is in the picture below

Rus_ich [418]

Answer:

$\Delta\text{H}_1+2\Delta\text{H}_2-\Delta\text{H}_3$

Explanation:

Hess's Law of Constant Heat Summation states that if a chemical equation can be written as the sum of several other chemical equations, the enthalpy change of the first chemical equation is equal to the sum of the enthalpy changes of the other chemical equations. Thus, the reaction that involves the conversion of reactant A to B, for example, has the same enthalpy change even if you convert A to C, before converting it to B. Regardless of how many steps it takes for the reactant to be converted to the product, the enthalpy change of the overall reaction is constant.

With Hess's Law in mind, let's see how A can be converted to 2C +E.

$\bf{\text{A} \rightarrow 2\text{B}}$ (Δ $\text{H}_1$ ) -----(1)

Since we have 2B, multiply the whole of II. by 2:

$\bf{2\text{B} \rightarrow 2\text{C} +2\text{D}}$ (2Δ $\text{H}_2$ ) -----(2)

This step converts all the B intermediates to 2C +2D. This means that the overall reaction at this stage is $\text{A} \rightarrow 2\text{C} +2\text{D}$ .

Reversing III. gives us a negative enthalpy change as such:

$\bf{2\text{D} \rightarrow \text{E}}$ (-Δ $\text{H}_3$ ) -----(3)

This step converts all the D intermediates formed from step (2) to E. This results in the overall equation of $\text{A} \rightarrow 2\text{C} +\text{E}$ , which is also the equation of interest.

Adding all three together:

$\text{A} \rightarrow 2\text{C}+\text{E}$ ( $\bf{\Delta\text{H}_1+2\Delta\text{H}_2-\Delta\text{H}_3 }$ )

Thus, the first option is the correct answer.

Supplementary:

To learn more about Hess's Law, do check out: brainly.com/question/26491956

4 0

1 year ago

A sample of pure lithium chloride contains 16% lithium by mass. What is the % lithium by mass in a sample of pure lithium carbon

Anna35 [415]

Answer:

Percentage lithium by mass in Lithium carbonate sample = 19.0%

Explanation:

Atomic mass of lithium = 7.0 g; atomic mass of Chlorine = 35.5 g; atomic mass of carbon = 12.0 g; atomic mass of oxygen = 16.0 g

Molar mass of lithium chloride, LiCl = 7 + 35.5 = 42.5 g

Percentage by mass of lithium in LiCl = (7/42.5) * 100% = 16.4 % aproximately 16%

Molar mass of lithium carbonate, Li₂CO₃ = 7 * 2 + 12 + 16 * 3 =74.0 g

Percentage by mass of lithium in Li₂CO₃ = (14/74) * 100% = 18.9 % approximately 19%

Mass of Lithium carbonate sample = 2 * 42.5 = 85.0 g

mass of lithium in 85.0 g Li₂CO₃ = 19% * 85.0 g = 16.15 g

Percentage by mass of lithium in 85.0 g Li₂CO₃ = (16.15/85.0) * 100 % = 19.0%

Percentage lithium by mass in Lithium carbonate sample = 19.0%

3 0

3 years ago