When a 6.50 g sample of solid NaOH dissolves in 100.0g of water in a coffee-cup calorimeter, the temperature rises from 21.6°C to 37.8°C. Calculate the ∆H (in kJ/mol NaOH) for the solution process. (Assume the specific heat of the solution formed is 4.18 J/g-K)
NaOH(s) ® Na+ (aq)+ OH–(aq)

Answer:

no I'm about to say we will be didn't 1,600 we will 500

Answer: oh i thought i knew it nvm im sorry love

Explanation:

A, the total number of valence electron is 24 for Silicon Tetrachloride , SiCl₄ .

In Lewis Dot structure S=N-A is used to calculate the total number of shared and unshared electrons in a molecule.

S is the number of shared electrons ,N is the number of total valence shell electrons required by all the atom of the molecule, A is the total number of valence electrons available from all the atoms in the molecule

For SiCl₄,

• We have to first count the valence electron on each atom that is coming to form a molecule .

Valence electron on Si = 4

Valence Electron on Cl = 7

Total valence electron on SiCl₄ = 4+ 4 * 7 = 32

• Then we find the least electronegative atom in the molecule and place it at the center , In SiCl₄ , Si has 1.8 and Cl has 3.16 and so Si is placed at the center and four Cl atoms are connected with a single bond

• A single bond takes up 2 valence electron and so for four bonds 8 valence electrons have been occupied , so we are left with 32-8=24 valence electrons.

Therefore In the Lewis Dot structure S=N-A , Total number of valence electrons available from all the atoms in molecule of SiCl₄ is 24.

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Answer:

a. 3; b. 5; c. 10; d. 12

Explanation:

pH is defined as the negative log of the hydronium concentration:

pH = -log[H₃O⁺] (hydronium concentration)

For problems a. and b., HCl and HNO₃ are strong acids. This means that all of the HCl and HNO₃ would ionize, producing hydronium (H₃O⁺) and the conjugate bases Cl⁻ and NO₃⁻ respectively. Further, since all of the strong acid ionizes, 1 x 10⁻³ M H₃O⁺ would be produced for a., and 1.0 x 10⁻⁵ M H₃O⁺ for b. Plugging in your calculator -log[1 x 10⁻³] and -log[1.0 x 10⁻⁵] would equal 3 and 5, respectively.

For problems c. and d. we are given a strong base rather than acid. In this case, we can calculate the pOH:

pOH = -log[OH⁻] (hydroxide concentration)

Strong bases similarly ionize to completion, producing [OH⁻] in the process; 1 x 10⁻⁴ M OH⁻ will be produced for c., and 1.0 x 10⁻² M OH⁻ produced for d. Taking the negative log of the hydroxide concentrations would yield a pOH of 4 for c. and a pOH of 2 for d.

Finally, to find the pH of c. and d., we can take the pOH and subtract it from 14, giving us 10 for c. and 12 for d.

(Subtracting from 14 is assuming we are at 25°C; 14, the sum of pH and pOH, changes at different temperatures.)

Answer:

Atomic number: 26

Atomic mass: 56

Net charge: +3

Explanation:

The substance heats up relatively quickly means less energy needed for the rise in temperature. Therefore, the substance is having low specific heat.

Of all liquids, water has the highest specific heat capacity. The amount of heat that one gram of a substance needs either absorb or lose in order to change its temperature by one degree Celsius is known as specific heat. A compound with "low specific heat" will raise its temperature considerably more quickly than a compound with "high specific heat." J/kg C or J/g C are the units for specific heat. While substances with (high or low) particular heats will be more challenging to heat up, substances with (high or low) specific heats will heat up readily.

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Answer:

The group that tests the variable.

Explanation:

The group that tests the variable is a control group.

Answer:

C when testing the group put the varible in control

Answer:

density = (mass) divided by (volume)

or just D = M/V

Answer:

A solid's particles are packed closely together. The forces between the particles are strong enough that the particles cannot move freely; they can only vibrate. As a result, a solid has a stable, definite shape and a definite volume. Solids can only change shape under force, as when broken or cut.

When you dissolve a cube of sugar in a cup of tea, the entropy of the system increases.

The system in this context consists of the sugar cube and the tea. Initially, the sugar molecules are arranged in a crystalline structure, which is an ordered state. When the sugar cube is dissolved in the tea, the sugar molecules spread out and mix with the tea molecules, forming a more disordered state. As the randomness of the system increases, so does its entropy. Therefore, the entropy of the system increases when you dissolve a cube of sugar in a cup of tea.

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Answer:

approximately 1.772 grams

Explanation:

molecular mass of AlCl3 is 132 g per mole and of Al(OH)3 is 78 g per mole

the reaction is

AlCl3 + 3 NaOH ---> Al(OH)3 + 3 NaCl

from the reaction it is clear that 1 mole AlCl3 makes 1 mole Al(OH)3

implies 132g AlCl3 gives 78g Al(OH)3

Implies 3g AlCl3 gives

\(3 \times \frac{132}{78} = 1.772 \: g \: al(oh)3\)

Answer:

is there a way of reducing light pollution at the edges of a forest work?

Answer:

Height z= 2.115 cm

Explanation:

The formula for area of a trapezoid is ;

A=1/2(a+b)h where A is area, a and b are the lengths of parallel sides and h is the height of the trapezoid.

Given in the question;

A= 20 cm²

a=( 2z + 3 ) cm

b= (6z-1) cm

h= z =? unknown

Substitute in the formula as;

A=1/2(a+b)h

20=1/2(2z+3+6z-1)z -----------multiply both sides of the equation by 2

40= (2z+3+6z-1)z  -----------collect like terms as

40 =(2z+6z+3-1)z

40=(8z+2)z -----open brackets as

40=8z²+2z --------- form a quadratic equation

8z²+2z-40 = 0 -----solve the quadratic equation to find value of z

z²+0.25z-5=0

z= 2.115

Answer:

zero gram present after the reaction is completed

0.10 M HCN and 0.10 M LiCN solution is a good buffer system among the given options.

A buffer system consists of a weak acid and its conjugate base. The main function of the buffer solution is to resist the change in pH. Among the given options the first option has HCN as acid and LiCN as the conjugate base. In the second option, HNO₃ is used as an acid, as HNO3 is a strong acid so it is not suitable for a good buffer solution. In the third option, HCl is used as an acid which is also a strong acid so not suitable for a buffer solution. In the last option again HNO₃ is used as an acid which is a strong acid. So the best option is the 1st one having HCN, which is a weak acid.

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The answer is 0.5810 M.

Molar concentration means molarity is defined as the moles of solute per litre of solution. Its unit is M.

How the molar concentration of acetic acid in vinegar is determined?

Base is \(NaOH\) and its volume (V2) = 10.0 mL and let molairty be M2.

Now, on complete neutralization, we know that-

\(M1V1 = M2V2\\or\\M2 =\frac{M1V1}{V2} =\frac{(0.1931\ M) (30.09 mL)}{10.0 mL}\\ M2 = 0.5810 M\)

Hence, molar concentration of acetic acid in vinegar  is 0.5810 M.

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To determine the number of moles of water contained in 96.0 g, we need to use the molar mass of water. The molar mass of a substance is the mass of one mole of that substance, and it is calculated by adding up the atomic masses of all the atoms in the chemical formula.

The chemical formula for water is H2O, indicating that each molecule of water contains two hydrogen atoms and one oxygen atom. The atomic masses of hydrogen and oxygen are approximately 1 g/mol and 16 g/mol, respectively.

To calculate the molar mass of water, we multiply the atomic mass of hydrogen by 2 (since there are two hydrogen atoms in water) and add it to the atomic mass of oxygen:

Molar mass of water = (2 x 1 g/mol) + (1 x 16 g/mol) = 18 g/mol

Now, we can use the molar mass to determine the number of moles in 96.0 g of water. We divide the given mass by the molar mass:

Number of moles = Mass / Molar mass = 96.0 g / 18 g/mol ≈ 5.33 mol

Therefore, there are approximately 5.33 moles of water in 96.0 g of water.

It is important to note that the molar mass of water can be rounded to three decimal places since the given mass has only three significant figures (96.0 g).

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When carbon dioxide (CO2) dissolves in water (H2O), it reacts to form carbonic acid (H2CO3). This reaction can be represented by the equation: CO2(g) + H2O(l) ↔ H2CO3(aq)

The equilibrium constant for this reaction, denoted as K, expresses the ratio of the concentrations of the products to the concentrations of the reactants at equilibrium. In this case, the equilibrium equation is: CO2(g) ↔ CO2(aq)
The concentration of carbon dioxide dissolved in water is primarily represented by CO2(aq). The K value provides information about the extent of the reaction at equilibrium.

It's important to note that the equilibrium constant, K, is influenced by factors such as temperature, pressure, and the concentrations of reactants and products. These factors can shift the equilibrium in favor of the reactants or products.
For example, if the concentration of carbon dioxide in the air above the water increases, the equilibrium will shift to the right, favoring the formation of dissolved CO2.

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Answer:

nucleus

Explanation:

An atom itself is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of the atom called the nucleus and the electrons fly around above the nucleus in a small cloud.

hope that helps!

The Earth's surface is not covered with the same materials ; however, some areas share similar materials.Several drilling sites have been dug in various regions of the planet to analyze the Earth's surface.

Each drilling site is unique, with differing characteristics and results. Despite these differences, all of the drilling sites analyzed offer scientists a more in-depth knowledge of the Earth's surface.In essence, the scientific drilling sites each had different lithologies, stratigraphies, and geologies. Each site had different types of rocks, depths, and ages, which led to varying drilling conditions, depths, and equipment used. Different types of equipment were also used to reach the depths required, which was a significant difference in each drilling site.The scientific drilling sites also had different purposes. Scientists had specific goals they wanted to achieve at each location. For example, the scientific drilling site in the Iceland region was focused on analyzing a unique layer of igneous rocks. The primary objective was to investigate the formation of the rock layer.The same materials were not found at each scientific drilling site.

Still, they had some similarities. They all provided geologists with vital information about the Earth's surface. The data provided from each drilling site was used to piece together the Earth's geologic history and how it has changed over time.

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Step 1 - Understanding the definition of molar concentration

Molar concentration (M or mol/L) is defined as the quotient between the number of moles (n) and the total volume of the solution (V):

Therefore, if the volume of the solution and its final concentration are known, we can use the equation to find the required number of moles.

Step 2 - Finding the required number of moles

The solution's concentration is 0.46 M and its volume is 250 ml. The volume must always be used in L, so:

Therefore, 0.115 moles would be required.

The reaction of the hydrogen and the chlorine atoms would lead to the formation of HCl

In this reaction, each chlorine molecule (Cl2) breaks apart into two chlorine atoms (Cl), and each hydrogen molecule (H2) breaks apart into two hydrogen atoms (H). These reactive atoms then combine to form hydrogen chloride molecules (HCl).

It's worth noting that the reaction between hydrogen gas and chlorine gas is highly exothermic and releases a significant amount of energy.

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\(\ch{AgF(aq) + Na2S(aq) - > Ag2S(s) + 2NaF(aq)}\)When AgF(aq) and Na2S(aq) solutions are mixed, a solid Ag2S is formed. The ionic equation for this reaction is \(\ch{AgF(aq) + Na2S(aq) - > Ag2S(s) + 2NaF(aq)}\), and the net ionic equation is \(\ch{Ag+(aq) + S^{2-}(aq) - > Ag2S(s)}.\)

To determine whether a solid forms when solutions containing AgF(aq) and Na2S(aq) are mixed, we need to consider the solubility rules for these salts.

The solubility rules state that most silver salts, including AgF, are insoluble in water, except for those formed with nitrate, acetate, and perchlorate ions. On the other hand, most sulfide salts, including Na2S, are soluble in water, except for those formed with calcium, strontium, barium, and lead ions.

Since AgF is insoluble and Na2S is soluble, a solid will form when these solutions are mixed. The balanced ionic equation for this reaction is:

\(\ch{AgF(aq) + Na2S(aq) - > Ag2S(s) + 2NaF(aq)}\)

To write the net ionic equation, we remove the spectator ions that do not participate in the formation of the solid. In this case, Na+ and F- are spectator ions. The net ionic equation is:

\(\ch{Ag+(aq) + S^{2-}(aq) - > Ag2S(s)}.\)

In summary, when AgF(aq) and Na2S(aq) solutions are mixed, a solid Ag2S is formed. The ionic equation for this reaction is

AgF(aq) + Na2S(aq) → Ag2S(s) + 2NaF(aq),

And the net ionic equation is

\(\ch{Ag+(aq) + S^{2-}(aq) - > Ag2S(s)}.\)

This reaction is possible because AgF is insoluble while Na2S is soluble according to the solubility rules.

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Answer:

B

Explanation:

The heated atmosphere cause glaciers and ice caps to melt causing the sea level to rise

Answer:

Rising temperatures melt more glaciers and polar ice caps, which add water to the ocean.

Explanation:

The resultant of the reaction when their change in Enthalpy is positive, change in Entropy is negative and the gibbs free energy is positive is  non spontaneous Reaction. Under the specified conditions, this reaction does not promote the creation of products. A reaction must be endothermic, followed by a reduction in entropy, or both in order to be considered nonspontaneous.

The following are the relationships between spontaneity, entropy, and enthalpy:

Gibbs energy will be negative at all temperatures if enthalpy is negative and entropy is positive.

At low temperatures, Gibbs energy will be negative if enthalpy and entropy are both negative.

At any temperature, Gibbs energy won't be negative while enthalpy is positive and entropy is negative. There wouldn't be an unforeseen response.

At high temperatures, Gibbs energy will be negative while enthalpy and entropy are both positive.

As a result, the change in reaction free energy is what ultimately determines whether a reaction is possible.

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Answer:

B

Explanation:

Answer:

Soluble fiber attracts water and turns to gel during digestion. This slows digestion. Soluble fiber is found in oat bran, barley, nuts, seeds, beans, lentils, peas, and some fruits and vegetables. It is also found in psyllium, a common fiber supplement.:

Answer: C

Explanation:

Don’t trust the other person it’s not A

*view photo for answer*

pay attention! the answer choices aren't always in the same order!

Answer:

A). 2.1 × \(10^{-2}\)

Explanation:

Given reaction,

2\(HF\) (g) ⇄ \(H_{2}\) (g) + \(F_{2}\) (g)

The concentrations are as following;

\(HF\) = 5.82 × \(10^{-2}\) M

\(H_{2}\) = 8.4 × \(10^{-3}\) M

\(F_{2}\) = 8.4 × \(10^{-3}\) M

So,

\(K_{eq}\) = [(\(H_{2}\) ) × (\(F_{2}\))] ÷ [\(HF\)]^2

Now,

We can determine the value of \(K_{eq}\) by substituting the values in above formula:

\(K_{eq}\) = [ (8.4 × \(10^{-3}\) M) × (8.4 × \(10^{-3}\) M)] ÷ [(5.82 × \(10^{-2}\))^2

= 2.08 * \(10^{-2}\)

=  2.1 × \(10^{-2}\)

∵ \(K_{eq}\) = 2.1 × \(10^{-2}\)

Thus, option A is the correct answer.