It is important for scientists to know how much energy is given off or absorbed in a chemical reaction. Which options below would indicate an exothermic reaction?

delta H = –

delta H = +

Energy is considered a reactant in the reaction: A + B + energy ---> C + D

Energy is considered a product in the reaction: A + B ---> C + D + energy

Energy is released in the reaction.

Energy is absorbed in the reaction.

Answer:

pH = 3.68

Explanation:

We can solve this problem by using Henderson-Hasselbach's equation:

Assuming we have 1 L of the buffer solution then the molar concentrations of formate and formic acid would be:

We now have all required data to calculate the pH:

Answer:

[tex]pH = - log[H {}^{ + } ] \\ = - log(0.0000067) \\ pH = 5.17[/tex]

Answer:

Density = 19.3 g/cm³

Explanation:

In order to answer this question we need to keep in mind the following definition of density:

As both the mass and the volume are given by the problem, we can proceed to calculate the density of gold:

Answer:

Al°(s)  + 3Ag⁺(aq) => Al⁺³(aq) + 3Ag(s)

Explanation:

Oxidation:                            Al°(s) =>   Al⁺³(aq) + 3e⁻

Reduction:           3Ag⁺(aq) + 3e⁻ => 3Ag°(s)

_________________________________________

Net Rxn:           Al°(s)  + 3Ag⁺(aq) => Al⁺³(aq) + 3Ag(s)

One mole of neutral aluminum atoms (Al°(s)) undergo oxidation delivering 3 moles  of electrons to 3 moles silver ions (3Ag⁺³(aq)) that are reduced to 3 moles of neutral silver atoms (3Ag°(s)) in basic standard state 25°C; 1atm.

A balanced equation obeys the law of conservation of mass. According to the law of conservation of mass, mass can neither be created nor be destroyed. The coefficient of silver is 3.

A balanced chemical equation can be defined as the chemical equation in which the number of reactants and products on both sides of the equation are equal. The amount of reactants and products on both sides of the equation will be equal in a balanced chemical equation.

The numbers which are used to balance the chemical equation are called the coefficients. The coefficients are the numbers which are added in front of the formula.

The balanced chemical equation for the given redox reaction is given as:

Al (s) + 3 Ag⁺ (aq)  → Al³⁺ (aq) + 3Ag (s)

Thus the coefficient of silver is 3.

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Answer:

40 grams of KCI are required to make 500 ml of 8% solution.

Answer:

the melting process begins right away because the air temperature around the ice cubes is warmer than the temperature in the freezer

Answer:

n-hexane

2-methylpentane

3-methylpentane

2,2-dimethylbutane

2,3-dimethylbutane

Explanation:

There are 5 structural isomers of C6H14.

n-hexane

2-methylpentane

3-methylpentane

2,2-dimethylbutane

2,3-dimethylbutane

Answer:

96 grams

Explanation:

Answer: photosynthesis

Explanation:

Answer:

Federal law is a law that may protect people from digital attacks such as cyberbullying.

Explanation:

Although it is mostly based on the situation, federal law does protect those who suffer from cyberbullying. The attackers may be charged with defamation, since cyberbullying consists of spreading false information about someone on the internet, that's when the law comes in.

Answer:

e) C5H10O3

Explanation:

According to the information given in this question;

50.84% represents C

8.53% represents H

[100% - (50.84 + 8.53)]

= 100 - 59.37

= 40.63% of Oxygen (O)

This percentage means that;

Carbon = 50.84g

Hydrogen = 8.53g

Oxygen = 40.63g

By dividing by their respective atomic masses, we convert to moles:

C = 50.84g ÷ 12 = 4.24mol

H = 8.53g ÷ 1 = 8.53mol

O = 40.63g ÷ 16 = 2.54mol

Next we divide by the smallest no of the values (2.54mol)

C = 4.24 ÷ 2.54 = 1.669

H = 8.53 ÷ 2.54 = 3.358

O = 2.54 ÷ 2.54 = 1

To get a simple whole number ratio, we multiply the results by 3

C = 1.669 × 3 = 5.007

H = 3.358 × 3 = 10.074

O = 1 × 3 = 3

Simple whole number ratio of carbon, hydrogen and oxygen is 5:10:3. Hence, the empirical formula is C5H10O3.

Answer:

Assuming 20.0 mL of 0.2 M NaOH is used to neutralize 30 mL of the HCl of unknown concentration, the concentration of the hydrochloric acid is 0.133 M.

Note: The volume of NaOH used isnot given and issp to be determined by titration.

Explanation:

The question is a lab activity. Therefore, the volume of 0.2 M NaOH required for the neutralization of 30.0 mL of hydrochloric acid of unknown concentration is to be determined from titration. However, assuming a certain volume of the base is used for the complete neutralization of the acid, the concentration of the acid can be calculated.

Assuming 20.0 mL of 0.2 M NaOH is used to neutralize 30 mL of the HCl of unknown concentration, the concentration of the hydrochloric acid can be calculated thus:

Step 1: Balanced chemical equation of reaction:

HCl + NaOH ---> NaCl + H₂O

From the equation of the reaction, 1 mole of NaOH reacts with 1 mole of HCl to produce 1 mole of NaCl and water.

Step 2: Determine the number of moles of NaOH in 20.0 mL of 0.200 M solution

Molarity = number of moles/volume in Litres

Number of moles = molarity × volume in litres

Volume of NaOH in litres = 20 ml × 1 litre/1000ml = 0.02 litres

Number of moles NaOH = 0.02 L × 0.2 M = 0.004 moles

Therefore, 0.00 M of NaOH reacted with 0.004 moles of HCl

Step 3: Determine concentration of HCl

Molarity or concentration = number of moles / volume in litres

Number of moles of HCl = 0.004 moles

Volume of HCl in litres = 30.0 mL × 1 L/1000 mL = 0.03 L

Concentration of HCl = 0.004 moles / 0.03 L = 0.133 M

Therefore, assuming 20.0 mL of 0.2 M NaOH is used to neutralize 30 mL of the HCl of unknown concentration, the concentration of the hydrochloric acid is 0.133 M.

Answer:

Easy my dude let me help you out

A.In

B.27

C.73

D.49

E.56

F.56

G.114

H.180

Also with protons and electrons they equal the same atomic number

Answer:

The pressure will be 933.33 Kpa

Explanation:

Given that:

Volume V₁ = 200 cm³  (note, there is a mistake in the volume. It is supposed to be 200 cm³)

Pressure P₁ = 700 Kpa

Pressure P₂ = ??? (unknown)

Volume V₂ = 150 cm³

Temperature = constant

Using Boyle's law:

PV = constant

i.e.

P₁V₁ = P₂V₂

700 Kpa × 200 cm³ = P₂ × 150 cm³

P₂ = (700 Kpa × 200 cm³)/150 cm³

P₂ = 933.33 Kpa

Answer:

[tex]x = 2[/tex]

Explanation:

General formula for alkanes

[tex]C _{n}H _{2n + 2}[/tex]

since H = 6

[tex]2n + 2 = 6 \\ 2n = 4 \\ n = 2 \\ since \: x = n\\ \therefore \: x = 2[/tex]

Answer:

x=2

Explanation:

Because alkanes have a general formula of CnH(2n+2).

We known that 2n+2=6, so we solve for n.

2n+2=6

2n=4

n=2

Thus, there are 2 carbon atoms.

Answer:

(a) The molality of this solution is 0.0613[tex]\frac{moles}{kg}[/tex]

(b)The molality of this solution is 2.04[tex]\frac{moles}{kg}[/tex]

Explanation:

The molality (m) of a solution is defined as the number of moles of solute present per kg of solvent.

The Molality of a solution is determined by the expression:

[tex]Molality=\frac{number of moles of solute}{kilograms of solvent}[/tex]

Molality is expressed in units [tex]\frac{moles}{kg}[/tex]

(a) You have 14.3 g of sucrose (C₁₂H₂₂O₁₁), the solute. With the molar mass of sucrose being 342 [tex]\frac{g}{mole}[/tex], then 14.3 grams of the compound represents the following number of moles:

[tex]14.3 grams*\frac{1 mole}{342 grams} =[/tex] 0.042 moles

Having 685 g= 0.685 kg (being 1000 g= 1 kg) of water, the solvent, molality can be calculated as:

[tex]molality=\frac{0.042 moles}{0.685 kg}[/tex]

Solving:

molality= 0.0613[tex]\frac{moles}{kg}[/tex]

The molality of this solution is 0.0613[tex]\frac{moles}{kg}[/tex]

(b) In this case you have 7.15 moles of ethylene glycol (C₂H₆O₂), the solute, in 3505 g (equal to 3.505 kg) of water, the solvent, molality can be calculated as:

[tex]molality=\frac{7.15 moles}{3.505 kg}[/tex]

Solving:

molality= 2.04[tex]\frac{moles}{kg}[/tex]

The molality of this solution is 2.04[tex]\frac{moles}{kg}[/tex]

Answer:

For A: The average molecular speed of Ne gas is 553 m/s at the same temperature.

For B: The rate of effusion of [tex]SO_2[/tex] gas is [tex]1.006\times 10^{-3}mol/hr[/tex]

Explanation:

For A:

The average molecular speed of the gas is calculated by using the formula:

[tex]V_{gas}=\sqrt{\frac{8RT}{\pi M}}[/tex]

     OR

[tex]V_{gas}\propto \sqrt{\frac{1}{M}}[/tex]

where, M is the molar mass of gas

Forming an equation for the two gases:

[tex]\frac{V_{Ar}}{V_{Ne}}=\sqrt{\frac{M_{Ne}}{M_{Ar}}}[/tex]          .....(1)

Given values:

[tex]V_{Ar}=391m/s\\M_{Ar}=40g/mol\\M_{Ne}=20g/mol[/tex]

Plugging values in equation 1:

[tex]\frac{391m/s}{V_{Ne}}=\sqrt{\frac{20}{40}}\\\\V_{Ne}=391\times \sqrt{2}=553m/s[/tex]

Hence, the average molecular speed of Ne gas is 553 m/s at the same temperature.

For B:

Graham's law states that the rate of diffusion of a gas is inversely proportional to the square root of the molar mass of the gas. The equation for this follows:

[tex]Rate\propto \frac{1}{\sqrt{M}}[/tex]

Where, M is the molar mass of the gas

Forming an equation for the two gases:

[tex]\frac{Rate_{SO_2}}{Rate_{Xe}}=\sqrt{\frac{M_{Xe}}{M_{SO_2}}}[/tex]          .....(2)

Given values:

[tex]Rate_{Xe}=7.03\times 10^{-4}mol/hr\\M_{Xe}=131g/mol\\M_{SO_2}=64g/mol[/tex]

Plugging values in equation 2:

[tex]\frac{Rate_{SO_2}}{7.03\times 10^{-4}}=\sqrt{\frac{131}{64}}\\\\Rate_{SO_2}=7.03\times 10^{-4}\times \sqrt{\frac{131}{64}}\\\\Rate_{SO_2}=1.006\times 10^{-3}mol/hr[/tex]

Hence, the rate of effusion of [tex]SO_2[/tex] gas is [tex]1.006\times 10^{-3}mol/hr[/tex]

Answer:

The cation affects the intensity of the color more than the color of the solution.

Explanation:

According to Beer Lambert law, the intensity of the colour of the solution depends on the concentration of the specie responsible for the colour in the solution.

Let us recall that transition metal compounds are coloured in solution due to electronic transitions.

Therefore, the cation affects the intensity of the color more than the color of the solution.

Answer:

5.81 moles

Explanation:

To find the number of moles (n) in 3.5 x 10²⁴ molecules of methane gas, we divide the number of molecules by Avagadro's number (nA). That is,

n = number of molecules ÷ 6.02 × 10²³

According to this question, 3.5 x 10^24 molecules of methane gas was given, hence,

n = 3.5 × 10²⁴ ÷ 6.02 × 10²³

n = 3.5/6.02 × 10(24 - 23)

n = 0.5814 × 10¹

n = 5.81 moles

Answer:

NaOH is the limiting reactant.

Explanation:

Hello there!

In this case, since the reaction taking place between sodium hydroxide and chlorine has is:

[tex]NaOH+Cl_2\rightarrow NaCl+NaClO+H_2O[/tex]

Which must be balanced according to the law of conservation of mass:

[tex]2NaOH+Cl_2\rightarrow NaCl+NaClO+H_2O[/tex]

Whereas there is a 2:1 mole ratio of NaOH to Cl2, which means that the moles of the former that are consumed by 0.85 moles of the latter are:

[tex]n_{NaOH}=0.85molCl_2*\frac{2molNaOH}{1molCl_2}\\\\n_{ NaOH}=1.7molNaOH[/tex]

Therefore, since we just have 1.23 moles out of 1.70 moles of NaOH, we infer this is the limiting reactant.

Regards!

A colloid is a mixture in which one substance of microscopically dispersed insoluble particles are suspended throughout another substance. However, some definitions specify that the particles must be dispersed in a liquid, and others extend the definition to include substances like aerosols and gels.

The types of colloids includes sol, emulsion, foam, and aerosol.

Explanation:

everything can be found in the picture

Answer:

C

Explanation:

u can't touch a chemical with bare skin

Answer:

touching a chemical with his or her bare skin.

Answer:

compound light microscope

Answer:

Both reactions are acid-base reactions

Explanation:

An acid base reaction is a reaction that occurs between an acid and a base. This reaction often leads to the formation of a salt in the process. The nature of the salt depends on the type of acid and base that reacted in the process.

Both HNO3 and H2SO4 are strong acids. However, ammonia is a weak base. The acid base reaction between ammonia and these strong acids is shown below;

HNO3(aq) + NH3(aq) ------>NH4NO3(aq)

H2SO4(aq) + 2NH3(aq) ----> (NH4)2SO4(aq)

Answer:

B. There is a very large percentage of C-12.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to realize that, since the average atomic mass is 12.01 amu, then the C-12, with an atomic mass of 12.000 am prevails over C-13 with an atomic mass of 13.003 amu as long as the average is nearer to the former.

In such a way, the answer will be B. There is a very large percentage of C-12.

Regards!

Answer:

the Molecular formula will be; C10H14O

Explanation:

Given the data in the question;

Chrysanthenone is an unsaturated ketone,

it has M+ = 150 and contains 2 double bond(s) and 2 ring(s).

molecular formula = ?

we know that ketone contain 1 oxygen and mass of oxygen is 16

so mass of the C and H remaining will be;

⇒ 150 - 16 = 134

Now we determine the number of C atoms;

⇒ 134 / 13 = 10

hydrocarbon with 10 hydrogen atom have CnH2n+2 means

⇒ ( 10 × 2 ) +2 = 22 hydrogens

But then we have 3 unsaturation meaning 6 hydrogens less and also we have ring meaning 2 more hydrogens

⇒ 22 - 6 - 2 = 14

Hence the Molecular formula will be; C10H14O

Answer: hello your question is poorly written below is the complete question

answer:

For N1 :  sp³  orbital

For N2:  p orbital

For N3 : p orbital

For N4 : sp² orbital

For N5 : sp² orbital

Explanation:

Determining the type of orbital in which the lone pair on each N atom will reside.

From the configuration attached below we can determine the type of orbital and they are ;

For N1 :  sp³  orbital

For N2:  p orbital

For N3 : p orbital

For N4 : sp² orbital

For N5 : sp² orbital