What happens in a flame test?
A. Electrons are excited to higher energy levels and their emissions
are observed.
B. Impurities in a sample are burned off in the flame until a pure
sample remains
C. Electrons are ejected from atoms when a sample is burned in the
flame.
D. A sample is melted in a flame to determine how much energy was

Answer:

As either mass increases, the gravitational force between them

increases.

Explanation:

According to Newton's law of universal gravitation;

F α m1m2/r^2

That is, the force between two masses in a gravitational field is directly proportional to the product of the two masses and inversely proportional to their distance apart.

Hence, as either of the masses increase, the force of gravitation between the two masses increases. Hence the answer.

Answer: In order for a substitution reaction to take place, at a minimum, loss of a leaving group and nucleophilic attack are needed.

Explanation:

When one group in a molecule is replaced by another one then it is called a substitution reaction.

For a substitution reaction reaction to occur at a minimum, it is necessary to have a leaving group that helps in creating a carbocation and hence a nucleophile can easily attack.

For example, [tex]CH_{4} + Cl_{2} + h\nu \rightarrow CH_{3}Cl + HCl[/tex]

Thus, we can conclude that in order for a substitution reaction to take place, at a minimum, loss of a leaving group and nucleophilic attack are needed.

Answer:

B

Explanation:

Spontaneous in chemical reactions means without any external input.

Occurring without added energy. Hence, option B is correct.

A spontaneous reaction is a reaction that supports the formation of products under the conditions under which the reaction is happening.

Spontaneous Reaction- a reaction that favours the formation of products at the conditions under which the reaction is occurring.

A non-spontaneous reaction can be made spontaneous if it is inside a controlled environment, this is what happens in nuclear power plants that create atomic fusion and fission in chambers that are controlled to control different particles to create nuclear active rays.

Hence, option B is correct.

Learn more about the spontaneous reaction here:

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Answer:

A metal M readily forms water-soluble sulphate MSO4, water-insoluble hydroxide M(OH)2 and oxide MO. The oxide and hydroxide are soluble in NaOH. The M is:

Answer:

The entropy change of carbon dioxide = 0.719 kJ/k

Explanation:

Given:

1.5 m - 3 insulated rigid tank contains 2.7 kg of carbon dioxide at 100 kPa

The objective is to determine the entropy change of carbon dioxide

Formula used:

ΔS=

Solution:

On considering,

[tex]C_{P} =0.846 kJ/kg K\\C_V=0.657 kJ/kg k\\[/tex]

ΔS=[tex]mc_{v} lu\frac{p_{2} }{P_{1} }[/tex]

On substituting the values,

ΔS=[tex]2.7*0.657lu\frac{150}{100}[/tex]

ΔS=0.719 kJ/k

The entropy change is "0.719 kJ/K".

Given values are:

Mass of tank,

Pressure,

Rised pressure,

Assumption of constant specific heat is,

As we know the formula,

→ [tex]\Delta S = mC_v \ ln(\frac{P_2}{P_1} )[/tex]

         [tex]= (2.7)(0.657) \ ln (\frac{150}{100} )[/tex]

         [tex]= 1.7739\times 0.4055[/tex]

         [tex]= 0.7193 \ kJ/K[/tex]

Thus above answer is right.

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Answer:

The appropriate answer is "1.96 mol".

Explanation:

The given values are:

Volume,

V = 26.5 L

Pressure,

P = 1.7 atm

Temperature,

T = 280 K

Now,

The number of moles (n) will be:

= [tex]\frac{PV}{RT}[/tex]

By substituting the values, we get

= [tex]\frac{1.7\times 26.5}{0.0821\times 280}[/tex]

= [tex]\frac{45.05}{22.988}[/tex]

= [tex]1.96 \ mol[/tex]

Answer:

15 mL of the solute

Explanation:

From the question given above, the following data were obtained:

Solution = 50 mL

Solvent = 35 mL

Solute =?

Solution is simply defined as:

Solution = solute + solvent

With the above formula, we can easily obtain the solute in the solution as follow:

Solution = 50 mL

Solvent = 35 mL

Solute =?

Solution = solute + solvent.

50 = solute + 35

Collect like terms

50 – 35 = solute

15 = solute

Solute = 15 mL

Therefore, 15 mL of the solute is required.

Answer: it will be basic

pH that ranges from 0-6 are acid

pH of EXACTLY 7 is neutral

pH greater than 7 are strongly basic or base

Answer:

Depends on molecule.

Explanation:

The number of the polypeptide chains present in the oligomer depends on the molecule. Some molecules have more polypeptide chains whereas some of them have less polypeptide chains. For example, Hemoglobin is a oligomer that consists of four Polypeptide Chains, two of these Polypeptide Chains are α-globin molecules, each comprise of 141 amino acids, and the other two are (β, γ, δ, or ε) globins, each consist of 146 amino acids.

Answer: A Bronsted-Lowry acid is defined as a substance that acts as a proton donor.

Explanation:

A substance that is able to donate a proton or hydrogen ion to another substance is a Bronsted-Lowry acid.

For example, HCl is a Bronsted-Lowry acid as it dissociates to give a hydrogen ion.

[tex]HCl \rightleftharpoons H^{+} + Cl^{-}[/tex]

Thus, we can conclude that a Bronsted-Lowry acid is defined as a substance that acts as a proton donor.

Answer:

I don't know what to say . just for points

Answer:

Classify each of the following as either macroscopic, microscopic or particulate:

a. a red blood cell.

b. a sugar molecule.

c. baking powder.

Explanation:

a. A red blood cell is a microscopic particle.

It can be viewed under a microscope.

b. A sugar molecule is also a microscopic substance.

It can be viewed under a microscope.

c. Baking powder is macroscopic substance.

Answer:

cell

chloroplast and cell wall

nucleus

life processes

cell membrane

shape and size

vacuole

Hope it helps

Answer:

v2=5.11L

Explanation:

given

v1=2.58L

N1=0.118mol

N2=0.234

v2=x

according to charles law V1/N1=V2/N2

2.58/0.118=V2/0.234

21.86=V2/0.234

21.86×0.234= v2

5.116L=v2

5.116L is the

answer or u can simplify it and make 5.1 L

Answer:

I don't understand the question

Explanation:

1. c

2. c

Answer:

1. b. A = B

2. c. A < B

Explanation:

Consider equimolar samples of different ideal gases at the same volume and temperature. (nA = nB)

Gas A has a higher molar mass than gas B. (MA > MB)

1. We can calculate the pressure using the ideal gas equation.

P = n × R × T / V

Since n, T and V are equal, the pressure of both gases are equal as well.

2. We can calculate the root-mean-square of the velocity using the following expression.

v(rms) = √(3RT/M)

There is an inverse relationship between speed and molar mass. Since A has a higher molar mass, it has a lower speed.

Answer:

5.0molO

Explanation:

To find the moles of oxygen in 2.5 moles of caffeine, we will first research caffeine's molecular formula: C8H10N4O2. From the molecular formula, we can see there are 2 oxygen atoms in every 1 molecule of C8H10N4O2.We can therefore multiply by the following mole ratio to get the moles of oxygen.

2.5molC8H10N4O2×2molO/1molC8H10N4O2 = 5.0molO.

Answer:

n = 2.23 moles

Explanation:

Given the following data;

Standard temperature = 273 K

Standard pressure = 101.325 kPa

Volume = 50 liter

R = 8.314 J/mol·K  

To find the number of moles, we would use the ideal gas law formula;

PV = nRT

Where;

Making n the subject of formula, we have;

[tex] n = \frac {PV}{RT} [/tex]

Substituting into the formula, we have;

[tex] n = \frac {101.325*50}{8.314*273} [/tex]

[tex] n = \frac {5066.25}{2269.722} [/tex]

n = 2.23 moles

Therefore, 2.23 moles of carbon dioxide at STP will fit in a 50 liter container.

Answer:

The rate law for the following reaction:

H2SiF6(aq)+2NaF(aq)+3H2O(aq)⟶Na2SiO3(s)+8HF(aq)

is second order in H2SiF6, zero order in NaF and first order in H2O.

Answer:

Hindi ko po ma gets sinasabi nyu pwedeng pakiayus

Answer:

1) volumetric

2) graduated

3) volumetric

Explanation:

A volumetric glassware is a glassware that is marked at a particular point. A typical example of a volumetric glassware is the volumetric flask. A volumetric glassware is capable of measuring only a specific volume of a liquid.

On the other hand, graduated glassware can measure a range of volumes of liquid. However, a volumetric glassware is still required where a high degree of accuracy is important.

Answer:

8.61 %

Explanation:

The percent of sodium hypochlorite in the bleach sample can be calculated using the following formula:

We input the data given by the problem:

Answer:

3-hexanol

1 -butanol

2-pentanol

Explanation:

Let us recall that chromic acid or chromate are strong oxidizing agents. When they are oxidized, their colour changes from orange to green.

This shows a reduction in chromic acid or chromate. The reaction of chromic acid or chromate with a primary alcohol yields a carboxylic acid while reaction with a secondary substrate yields an alkanal.

Note that Tertiary alkyl halides are not be oxidized hence reactions involving a point where invitation carried along occur.

3-ethyl-3-pentanol is a tertiary alkyl halide hence it can not be oxidized.

Answer:

A) 697 mL

Explanation:

First convert degrees Celsius to Kelvin.

That gives;

For T1; temp 1 (273 + 25.1)

= 298.1K

T2; temp 2 (273+60.7)

=333.7K

From the formula, (V1/T1) = (V2/T2)

To find V2 = (V1/T1) × T2

= (622.7/298.1) × 333.7.

= 697.06mL

~~ 697mL

Answer:

volume = mass/density

Here, volume = 80g/1.59gcm-3 → 50.314 cm3

Explanation:

The question is incomplete, the complete question is;

Suppose 0.377g of potassium acetate is dissolved in 250.mL of a 57.0mM aqueous solution of ammonium sulfate.

Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it.

Round your answer to 3 significant digits.

Answer:

0.0152 M

Explanation:

The equation of the reaction is;

2CH3COOK(aq) + (NH4)2SO4(aq)------> K2SO4(aq) + 2CH3COONH4(aq)

Number of moles of potassium acetate = 0.377g/98.15 g/mol = 0.0038 moles

Number of moles of ammonium sulphate = 250/1000L × 57 × 10^-3 = 0.014 moles

2 moles of potassium acetate yields 2 moles of ammonium acetate

Hence;

0.0038 moles of potassium acetate yields 0.0038 moles of ammonium acetate

Also

1 mole of potassium sulphate yields 2 moles of ammonium acetate

0.014 of potassium sulphate yields 0.014 × 2/1 = 0.028 moles of ammonium acetate

So potassium acetate is the limiting reactant.

Since 0.0038 moles of ammonium acetate is produced, the final concentration of potassium acetate is = 0.0038 moles of ammonium acetate/0.25L = 0.0152 M

Hence final concentration of acetate ions =0.0152 M

Answer:

2700 kg/m³

Explanation:

First let's convert 2.7 g/cm³ to kg/cm³, keeping in mind that 1 kilogram equals 1000 grams:

Finally we need to convert 0.0027 kg/cm³ to kg/m³, keeping in mind that 1 meter equals 100 centimeters, as follows:

The answer is 2700 kg/m³.

Answer:

SF2(aq) → S²⁺(aq) + 2F-(aq)

Explanation:

The sulfur difluoride, SF2, dissolves in water because the differences in electronegativities are considerable (3.98 for Fluorine and 2.58 for S) doing the F-S bond polar. As water is a polar solvent will dissolve the SF2 as follows:

As Fluorine has a > electronegativity than S, the Fluorine will be negative and S will be positive. Also, all halogen ions has a charge of -1.

Answer:

See detailed explanation.

Explanation:

Hello there!

In this case, according to the given description, it turns out possible for us to infer that the second fractionating column on top of the first one will favor the light product, in this case hexane as it has the lowest boiling point and molar mass; in such a way, we can tell the following:

a) The separation between hexane and heptane will be increased as a purer hexane-rich product will be obtained on the top of the second column.

b) Will be increased as well, because the second column will remove more heptane.

c) Also, more pure heptane will be obtained on the bottom of the two columns, yet the most favored yield will be that of hexane.

All of the aforementioned is possible due to the fact that the second column will remove the amount of heptane that could not be removed on the top of the first column by taking the vapor-liquid equilibrium further from the first column's maximum separation, which is known as distillation sequences.

Regards!

Answer:

The uncertainty principle is one of the most famous (and probably misunderstood) ideas in physics. It tells us that there is a fuzziness in nature, a fundamental limit to what we can know about the behavior of quantum particles and, therefore, the smallest scales of nature.