What is the main similarity among elements in group 2?

the concentration of [tex]\( \text{OH}^- \)[/tex] ions in the solution is [tex]\( 1.0 \times 10^{-3} \, \text{mol/L} \)[/tex].

To find the concentration of [tex]\( \text{OH}^- \)[/tex] ions [tex](\( [\text{OH}^-] \))[/tex] in a solution given the concentration of [tex]\( \text{H}^+ \)[/tex] ions [tex](\( [H^+] \))[/tex], we can use the fact that in water at [tex]\( 25^\circ \text{C} \)[/tex] [tex](\( 298 \text{K} \))[/tex], the product of [tex]\( [\text{H}^+] \)[/tex] and [tex]\( [\text{OH}^-] \)[/tex] is constant and equal to [tex]\( 1.0 \times 10^{-14} \, \text{mol/L} \)[/tex]. This is known as the ion product of water [tex](\( K_w \)).[/tex]

[tex]\[ K_w = [\text{H}^+] \times [\text{OH}^-] \][/tex]

Given [tex]\( [\text{H}^+] = 1 \times 10^{-1} \, \text{mol/L} \)[/tex], we can rearrange the equation to solve for [tex]\( [\text{OH}^-] \)[/tex]:

[tex]\[ [\text{OH}^-] = \frac{K_w}{[\text{H}^+]} \][/tex]

Substitute the given values:

[tex]\[ [\text{OH}^-] = \frac{1.0 \times 10^{-14} \, \text{mol/L}}{1 \times 10^{-1} \, \text{mol/L}} \][/tex]

[tex]\[ [\text{OH}^-] = 1.0 \times 10^{-14} \, \text{mol/L} \times \frac{1}{1 \times 10^{-1}} \, \text{mol/L} \][/tex]

[tex]\[ [\text{OH}^-] = 1.0 \times 10^{-14} \times 10^{1} \, \text{mol/L} \][/tex]

[tex]\[ [\text{OH}^-] = 1.0 \times 10^{-3} \, \text{mol/L} \][/tex]

Therefore, the concentration of [tex]\( \text{OH}^- \)[/tex] ions in the solution is [tex]\( 1.0 \times 10^{-3} \, \text{mol/L} \)[/tex].

Answer: Hypolimnion

Explanation:

The hypolimnion layer is found in the dense region of lake. It is bottom layer of water in a thermally stratified lake.

This region has lowest oxygen concentration,and it lies below the thermocline.

It is the deepest and coldest layer found in lake. It has very less oxygen and maximum amount of sediments is also found there.

There reaches no light so photosynthesis id not possible there. The temperature there is almost 4 °C throughout the year.

Final answer:

To find the heat released when 8.00 g of O₂ react, convert grams to moles based on O₂'s molar mass. Then, use stoichiometry to determine that 117.58 kJ of heat is released for 0.25 moles of O₂ reacting.

Explanation:

The question is asking how much heat is released when 8.00 g of O₂ (oxygen) reacts according to the provided chemical equation. To solve this, we first need to identify the molar mass of oxygen and then determine how many moles of O₂ is present in 8.00 g. The molar mass of O₂ is about 32.00 g/mol, so 8.00 g of O₂ is 0.25 moles. The balanced equation given is for 3 moles of oxygen gas, so we need to use stoichiometry to find out how much heat will be released when 0.25 moles react.

From the given equation, for every 3 moles of O₂ that react, 1411 kJ of heat is released. We can set up a proportion to find the heat released when 0.25 moles react:

(1411 kJ / 3 moles O₂) x 0.25 moles O₂ = 117.58 kJ

Therefore, when 8.00 g of O₂ react, 117.58 kJ of heat is released.

The standard Gibbs free energy of formation for Rubidium solid (Rb(s)), Hydrogen gas (H2(g)), and Lead solid (Pb(s)), which are each in their standard state, is zero by definition.

The standard Gibbs free energy of formation of any element in its most stable form is zero by definition. This means that for elements in their standard states, such as Rubidium solid (Rb(s)), Hydrogen gas (H2(g)), and Lead solid (Pb(s)), the standard Gibbs free energy of formation is zero.

Considering the standard state refers to the most stable form of an element at 1 atm pressure and 25°C, the correct answer to the question is that the standard Gibbs free energy of formation of all the listed elements, which are in their standard states, is zero.

https://brainly.com/question/28237924

#SPJ3

Answer:

"Radioactive half-life is increased by heating the isotope" is not true.

Explanation:

The radioactive half-life is the time required for half of any given amount of a substance (or isotope), to undergo radioactive decay.

This radioactive decay does not depend on the physical form of the substance nor it depends on the temperature.

Indented writing and spots are the examples of printing embedded in paper.

Printing is a process for mass reproducing text and images using a master form or template. The earliest non-paper products involving printing include cylinder seals and objects such as the Cyrus Cylinder and the Cylinders of Nabonidus. The earliest known form of printing as applied to paper was woodblock printing, which appeared in China before 220 AD for cloth printing. However, it would not be applied to paper until the seventh century.

Later developments in printing technology include the movable type invented by Bi Sheng around 1040 AD and the printing press invented by Johannes Gutenberg in the 15th century. The technology of printing played a key role in the development of the Renaissance and the Scientific Revolution and laid the material basis for the modern knowledge-based economy and the spread of learning to the masses.

Learn more about printing,here:

https://brainly.com/question/27646993

#SPJ3

Final answer:

The molal concentration of the aqueous solution with a freezing point of -0.58°C is 0.312 mol/kg, calculated using the formula for freezing point depression and the molal freezing-point depression constant for water.

Explanation:

To determine the molal concentration of the solution based on the given freezing point depression, we use the formula ΔTf = Kf × m, where ΔTf is the change in freezing point, Kf is the molal freezing-point depression constant for water, and m is the molality of the solution.

For water, Kf is -1.86°C/m. The change in freezing point (ΔTf) can be calculated as the difference from water's normal freezing point, 0°C, to the solution's freezing point, which is -0.58°C. Thus, ΔTf = 0°C - (-0.58°C) = 0.58°C.

Plugging the values into the equation:

ΔTf = Kf × m
0.58°C = (-1.86°C/m) × m
m = 0.58°C / -1.86°C/m
m = 0.312 mol/kg

Therefore, the molal concentration of the solution is 0.312 mol/kg.

The chemical reaction is given as:

[tex]Zn(s)+2HCl(aq)\rightarrow ZnCl_{2}(aq)+H_{2}(g)[/tex]

First, calculate the number of moles of zinc:

Number of moles = [tex]\frac{Given mass in g}{Molar mass}[/tex]

Given mass of zinc = [tex]14.0 g[/tex] and molar mass of zinc = [tex]65.4 g/mol[/tex]

Number of moles = [tex]\frac{14.0 g}{65.4 g/mol}[/tex]

= [tex]0.2140 moles[/tex]

Now, moles of hydrogen = [tex]number of moles of zinc\times \frac{1 mol of hydrogen}{1 mol of zinc}[/tex] ( as 1 mole of zinc gives 1 mole of hydrogen)

= [tex]0.2140\times \frac{1 mol of hydrogen}{1 mol of zinc}[/tex]

= [tex]0.2140 mol[/tex] of hydrogen.

Volume of hydrogen is calculated by:

[tex]PV=nRT[/tex]

where, P = pressure = 1 atm at STP

V = volume

n= number of moles

R = gas constant =  [tex]0.082 Latm/Kmol[/tex]

T = temperature= 273 K at STP

Now, insert the values in formula, we get

[tex]V=\frac{nRT}{P}[/tex]

[tex]V=\frac{0.2140 mol\times 0.082 Latm/Kmol\times 273 K}{1 atm}[/tex]

[tex]V=\frac{0.2140 mol\times 0.082 Latm/Kmol\times 273 K}{1 atm}[/tex]

[tex]V=4.790 L\simeq 4.80 L[/tex]

Thus, volume of hydrogen is [tex]4.80 L[/tex] i.e. second option is the correct answer.

Equal TO 50 degree because angle of incidence is equal to angle of reflection.

Answer:

equal to 50 degress

Explanation:

They are not attracted to each other because one is polar and one is nonpolar — is the correct answer

The partial pressure of nitrogen during the reaction if the volume is kept constant and nothing is added to the reaction mixture, then the pressure is decreases.

Pressure is defined as the force applied perpendicular to an object's surface per unit area over which that force is distributed. Gauge pressure is the pressure in relation to the surrounding atmosphere. Pressure is expressed using a variety of units.

Measuring the pressure of a substance is an important part of the manufacturing process in many industries. Obtaining accurate and meaningful data is critical in determining product quality and consistency. For these reasons, precise sensors are critical in gathering this information.

A pascal is a pressure of one newton per square metre, or one kilogram per metre per second squared in SI base units. For many purposes, this unit is inconveniently small, and the kilopascal (kPa) of 1,000 newtons per square meter is more commonly used.

Thus, The partial pressure of nitrogen during the reaction if the volume is kept constant and nothing is added to the reaction mixture, then the pressure is decreases.

To learn more about pressure, follow the link;

https://brainly.com/question/356585

#SPJ5

Option B and C both are balanced.

A chemical reaction is said to be balanced if all the constituent on the left side of the reaction arrow are equal to right side.

(A) The chemical reaction is as follows:

[tex]H_{2}+O_{2}\rightarrow H_{2}O[/tex]

There are 2 hydrogen atoms and 2 oxygen atoms on left side of the reaction arrow and 2 hydrogen and 1 oxygen on right hand side thus, number of oxygen atoms are not balanced.

Therefore, the above chemical reaction is not balanced.

(B) The chemical reaction is as follows:

[tex]2C_{2}H_{4}O+5O_{2}\rightarrow 4CO_{2}+4H_{2}O[/tex]

There are 4 carbon atoms, 8 hydrogen atoms and 12 oxygen atoms on both side of the reaction arrow thus, the chemical reaction is balanced.

(C) The chemical reaction is as follows:

[tex]K_{2}S+I_{2}\rightarrow 2KI+S[/tex]

There are 2 potassium atoms, 1 sulfur atom and 2 iodine atoms on both side of the reaction arrow thus, it is a balanced chemical reaction.

(D) The  chemical reaction is as follows:

[tex]CaCO_{3}+2HCl\rightarrow CaCl_{2}+2CO_{2}+H_{2}O[/tex]

There is 1 calcium atom, 1 carbon atom, 3 oxygen atoms, 2 hydrogen atoms and 2 chlorine atoms on left side of the reaction arrow and 1 calcium atom, 2 chlorine atoms, 2 carbon atoms, 5 oxygen atoms and 2 hydrogen atoms on right hand side of the reaction arrow. Thus, number of carbon and oxygen atoms are not balanced in the chemical reaction.

A balanced chemical reaction has the same and a balanced number of stoichiometry coefficients. Option B. [tex]\rm 2 C_{2}H_{4}O + 5 O_{2} \rightarrow 4 CO_{2} + 4 H_{2}O[/tex] and option D. [tex]\rm K_{2}S + I_{2} \rightarrow 2 KI + S[/tex] are balanced equations.

A balanced chemical reaction is the equated reaction and depiction of the chemical reactants and the products of the reaction. They have balanced stoichiometry coefficients on the left and the right side of the reaction.

In the second reaction,  [tex]\rm 2 C_{2}H_{4}O + 5 O_{2} \rightarrow 4 CO_{2} + 4 H_{2}O[/tex], the number of carbon atoms are four on both sides, 8 atoms of hydrogen on both sides and 12 atoms of oxygen balanced on both sides of the chemical reaction.

In the third reaction, [tex]\rm K_{2}S + I_{2} \rightarrow 2 KI + S[/tex], 2 atoms of potassium, 2 atoms of iodine and 1 atom of sulphur is balanced.

Therefore, reactions B and D are balanced reactions.

Learn more about the balanced equations here:

https://brainly.com/question/8033286