Balance these chemical equations. (Use the lowest possible whole number coefficients.)-K + Br2 → KBr

With the given materials following  experiment can be done

Electrical conductivity test:

Metals are good conductors of electricity, therefore when you join metals with a battery, wire, and bulb, you get a bulb.

Similarly, if nonmetals are poor electrical conductors, they may not ignite the bulb when attached to a wire and a battery.

Generally, the above method can be used to identify metals and non-metals. But there are some exceptions also,. Graphite, an allotrope of non-metal carbon, is a good conductor of electricity.

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The periodic chart has many different types of elements. Some elements are metals, some are nonmetals, and yet others are metalloids. Therefore, by electrical conductivity test, we can detect metal and non metal.

Metals are hard, conduct electricity, are ductile, lustrous, and malleable materials.

Since metals have free electrons that's why they can conduct electricity.  Since atoms in metals are very closely packed in a definite crystal solid. It is not brittle that is it can not be broken down easily.

Metals carry electricity well, therefore when you combine metals with a battery, wire, and bulb, you get a light. Similarly, if nonmetals are poor electrical conductors, when connected to a wire and a battery, they may not light the bulb.

Therefore, by electrical conductivity test, we can detect metal and non metal.

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Answer

Explanation

Given:

57.69% C, 11.54% H, and 30.77% O by mass,

Meaning:

Mass of carbon = 0.5769 g

Mass of Hydrogen = 0.1154 g

Mass of Oxygen = 0.3077 g

We know:

Molar masses of:-

C = 12.0107 g/mol

H = 1.00794 g/mol

O = 15.999 g/mol

Required: Empirical formula

Solution:

Step 1: Calculate the number of moles of the 3 atoms

C : 0.5769 g/12.0107 g/mol = 0.04826 mol

H : 0.1154 g/1.00794 g/mol = 0.1145 mol

O : 0.3077 g/15.999 g/mol = 0.0192

Step 2: Divide the moles by the lowest number of moles

In this case divide by 0.0192

C: 2.5

H: 6

O:1

Step 3: multiply by 2 to remove a decimal

C: 5

H: 12

O:2

Therefore the answer is: C5H12O2

Step 1 - "reading" the chemical equation

The given chemical equation is:

The proportion in moles for any chemical equation is given by the "bigger" numbers, those that come before the formula of the substances. We can use them to "read" what the equation is telling us:

1 mole of NaI react with 1 mole of Cu thus producing 1 mole of CuI2 and 1 mole of Na

Since the exercise has specifically asked us about the proportion between sodium iodide (NaI) and copper (Cu), we can simplify the statement to:

1 mole of NaI react with 1 mole of Cu

Therefore, we always need the same quantitie, in moles, of NaI and Cu for this reaction to occur completely.

Step 2 - Discovering how many moles of sodium iodide are required

Since the proportion between NaI and Cu, as we saw, is 1:1 in moles, whenever we use, let's say, x moles of Cu, we will need x moles of sodium iodide as well.

Therefore, the amount needed of sodium iodide would be exactly 3.2 moles.

Answer

D. 0.04 m (NH4)3PO4

Explanation

Boiling point elevation depends on the solvent, of course, but we're assuming water, and upon the concentration of the solute and how many particles into which the solute breaks. Colligative properties like boiling point elevation, depend on the total number of particles in solution. The solvent used here is water. So elevation in boiling point will be above a boiling point of water for all solutions.

ΔT= i x Kb x m,

Where i = van Hoff's factor, Kb = boiling point elevation constant of water = 0.512, m = molality

Higher ΔT will have a higher boiling point.

For 0.1 m CH4N₂O,

i = 1

ΔT = 1 x 0.512 x 0.1 = 0.0512

For 0.06 m HCI;

i = 2

ΔT = 2 x 0.512 x 0.06 = 0.06144

For 0.05 m CaCl2

i = 3

ΔT = 3 x 0.512 x 0.05 = 0.0768

For 0.04 m (NH4)3PO4;

i = 4

ΔT = 4 x 0.512 x 0.04 = 0.08192

For 0.07 m NaCl

i = 2

ΔT = 2 x 0.512 x 0.07 = 0.07168

0.04 m (NH4)3PO4 has the highest ΔT.

Therefore, the solution that has the highest boiling point would be D. 0.04 m (NH4)3PO4.

Answer: Particles in the solid phase are tightly compact and they vibrate, while particles in the liquid phase move freely, randomly, and with more room to move

Explanation:

ANSWER

Solutions are homogenous mixtures

EXPLANATION

A solution is a mixture that contains two or more substances in the right proportions.

Solution = solute + solvent

The solution is always a homogenous mixture because the substances are mixed in the right proportion

Hence, solutions are homogenous mixtures

Explanation:

Frequency and wavelength are inversely proportional to each other. The equation that relates them is:

f = c/λ

Where f is the frequency, λ is the wavelength and c is the speed of light.

f = ? λ = 843 nm c = 3.00 * 10^8 m/s

Before we replace these values into the formula we have to convert the wavelength from nm to m.

1 m = 1 * 10^9 nm

λ = 843 nm = 843 nm * 1 m/(1 * 10^9 nm)

λ = 8.43 *10^(-7) m

Finally we can replace the values into the equation and get the answer to our problem.

f = c/λ

f = (3.00 * 10^8 m/s)/( 8.43 *10^(-7) m)

f = 3.56 * 10^14 1/s

f = 3.56 * 10^14 Hz

Answer: the frequency of the light is 3.56 * 10^14 Hz

Answer

(C) nylon

Explanation

H2N-(CH2)6 -NH2 is hexamethylene diamine. The condensation reaction of hexamethylenediamine and adipic acid will produce a polymer, nylon.

Therefore, H2N-(CH2)6 -NH2 is one of the monomers of nylon

The correctanswer is (C)nylon

7.60grams

The formula for calculating the molarity of a solution is expressed as;

Given the following parameters

molarity of solution = 0.250M

volume of sample = 200mL

Substitute to determine the mole of the solute

Determine the required mass of FesO4

Hence the mass of FeSO4 is 7.60grams

Step 1 - Understanding the definition of each term

Mass: it measures the amount of matter of a body

Volume: it measures the space occupied by a body

Density: it's the mass divided by the volume

Weight: it is an indirect measure of the mass, since it also includes the action of gravity

Step 2 - Answering the exercise

As we can see, the definition that fits what is being asked is volume.

Answer: volume

The number of moles of H2O produced when 4 moles of H2SO4 are there is 8 moles of H2O

The reaction is  __H2SO4 + __Cr(OH)3 --> __Cr2(SO4)3 + __H2O. The reaction is as follows;

2Cr(OH)3 + 3H2SO4 → Cr2(SO4)3 + 6H2O

3 moles of H2SO4 produces 6 moles of H2O

1 mole of H2SO4 produces 2 moles of H2O

4 moles of H2SO4 produces 8 moles of H2O

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Explanation:

We are given: Ka1 = 8.0*10^-5

: Ka2 = 1.6*10^-12

: concentration = 0.240M

The value of Ka1>>Ka2, therefore Ka2 will not be considered in this calculations.

We then determine the concentration of H+ at equilibrium.

Let [C6H6O6-] = x, [H+] = x

Answer:

Explanation:

Here, we want to get the type of reactions listed

We proceed to evaluate the reactions one after the other:

a) This is a double replacement reaction. It usually occurs when molecules exchange ions in the course of their reaction leading to replacement in a molecule by an ion or a group of ions in the other molecule

b) This is a single replacement reaction which in other words could be referred to as a displacement reaction. This occurs usually when a metallic solid reacts with a solution of the salt of less reactive metal

c) This is a combination reaction. It is usually useful in the laboratory and industrial synthesis of some molecules

d) This is a decomposition reaction. It occurs when a particular molecule splits into the constituent molecules that make it up

Explanation:

Molarity, or concentration in amount of matter (mol/L), is the ratio between the amount of matter in the solute (n) and the volume of the solution in liters (V): M = n/V

Here we have:

m = 166 g of KI (solute)

V = 1000 mL = 1L (solution)

So we need to transform 166 g of KI into moles. We use the following formula:

n = m/MM

MM of KI is 166 g/mol

n = 166/166

n = 1 mol

So:

M = 1/1

M = 1 mol/L

Answer: M = 1 mol/L

The electronic distribution of the element is going to tell us how the electrons are distributed all across the atom.

There are some concepts to check:

Energy levels: They are numbered from 1 to 7 and correspond to the element period.

In each energy level, there are 4 sub energy levels: s, p, d, and f.

The quantic number l refers to the angular position of the angle that forms the element. The number of electrons present on this orbital is equal to the addition of the last energy level, in this case, 2.

The electronic configuration for this element is:

Then, the number of electrons in the last energy level is 8.

To determine the heat required (Q) to increase the temperature of a substance we can apply the following equation:

where,

m is the mass of the substance, 50g

Cp is the specific heat of the substance, 0.386J/g.K

deltaT is the temperature difference, 70K

Now, we have the values we need to calculate the heat required, we replace the known data into the equation:

The heat required to raise the temperature of 50 g of copper by 70 K will be 1347.5J

We have to write the net ionic equation for the reaction between HCl and NaHCO₃.

The molecular equation will show us the products of this equation.

Molecular equation:

HCl (aq) + NaHCO₃ (aq) ------> NaCl (aq) + CO₂ (g) + H₂O (l)

Now we can split this compounds into their ions to get the total ionic equation:

Total ionic equation:

H+ (aq) + Cl- (aq) + Na+ (aq) + HCO3- (aq) ----> Na+ (aq) + Cl- (aq) + CO₂ (g) + H₂O (l)

And finally we can identify the spectator ions. The ones that we have on both sides, they are Na+ and Cl-. We can cancel them out.

Net ionic equation:

H+ (aq) + HCO3- (aq) ----> CO₂ (g) + H₂O (l)

Answer: H+ (aq) + HCO3- (aq) ----> CO₂ (g) + H₂O (l)

Answer:

The specific heat of the metal is 0.69 J/g°C.

Explanation:

The given information from the exercise is:

• Metal,:

- Mass (massmetal): 52.3g

- Initial temperature (Tinitialmetal): 126.2°C

- Final temperature (Tfinalmetal): 35.5°C

• Water,:

- Mass (masswater):71.2g

- Initial temperature (Tinitialwater): 24.5°C

- Final temperature (Tfinalwater): 35.5°C

1st) It is necesary to write the Heat formula for both materials, the metal and water. In the case of water, we can solve the formula, because we have all the nedeed information:

• Metal,:

Water:

So, the heat absorbed by the water is 3,276.9 J.

2nd) In the end both materials reach the equilibrium temperature, because the heat released by the piece of metal is absorbed by the water, this is represented as:

Finally, we have to replace the heat of the metal equation (Qm) and the heat of water (Qw) to calculate the specific heat of the metal:

So, the specific heat of the metal is 0.69 J/g°C.

The reaction will occur.

The given chemical reaction is a double displacement reaction. In this reaction, the compoiunds will react to produce two different compounds.

The balanced form of the reaction is expressed as:

You can see that the reaction of cupper(II)sulphate and sodium carbonate produces sodium sulphate and copper(II)carbonate

Since most carbonate compounds are insoluble, hence the reaction will occur

We must first balance the equation, we have two atoms of nitrogen and hydrogen in the reactants, so we must put the coefficient 2 on the side of the products to balance the equation. The balanced equation of the reaction will be:

Now, to find the grams of NH that will be produced, we will follow these steps:

1. We find the moles of N2 and H2 by dividing the grams by the molar mass of each element.

Molar Mass N2=28.0g/mol

Molar Mass H2=2.0g/mol

2. By stoichiometry we find out which is the limiting reactant, we see that for each mole of H2 one mole of N2 reacts, therefore, the limiting reactant will be the one with the least number of moles. The other reactant will be the excess reactant

3. We find the moles of NH using the limiting reactant.

4. We find the grams of NH by multiplying the moles by the molar mass of NH.

5. We find how much of the excess reactant is left by subtracting the initial moles minus the reacting moles.

Let's proceed with the calculations

1. Moles of N2 and H2

2. Limiting reactant

We see that there are 22.5 moles of H2 and 1.25 moles of N2. The ratio N2 to H2 is 1/1, therefore, the limiting reactant will be the one with fewer moles, since it will be consumed faster. Therefore, the limiting reactant is nitrogen.

3. Moles of NH

The ratio NH to N2(Limiting reactant) is 2/1, therefore the moles of NH produced will be:

4. Mass of NH

5. Excess of H2

The mass of H2 left over will be:

Answer: 15.0 grams of NH will be produced and the excess will be 42.5g of H2

Let us first illustrate the reaction of Copper and Oxygen

• 2Cu +O2 → 2CuO

ratioon > 2 : 1

step 1 : determine moles of Cu and O2 .

(i) Moles Cu = mass Cu/Molar Mass Cu

= 63.6 g/ 63.546g/mol

=1.001 mol

(ii) moles O2 = mass Oxygen/Molar Mass Oxygen

= 71.6/32

= 2.238mol

Step 2 :

Experimental moles of Cu : O2

1.001moles : 2.238moles

take note that excess reactant is O2 and limiting reactant is Cu

Therefore moles of Oxygen that reacted = 1/2 moles of Cu

= 1/2 * 1.001 = 0.5moles

Mass of Oxygen reacted =0.5* 32 (oxygen Molar mass)

=16.01g

This means that 16.01 grams of Oxygen reacted , this value is not in the options provi

Answer

C. both

Explanation

Structures in option A and option B both corresponds to the name: pentanoic acid.

The correct answer is C. both

In order to know the values of the quantum numbers n, l and ml for al s4 orbital we go to a quantum table:

And as we can see to de 4s orbital correspond only the values:

n=4

l=0

ml=0

0.1M sugar < 0.1 M NaCl < 0.08M CaCl2 < 0.04 M Na2SO4​

First we must understand that the higher thecnoncentration of a compound, the lower the melting point. This shows that 0.04 m Na2SO4​ will have highest melting point followed by 0.08 M CaCl2

Since 0.1M of sBgar and 0.1M of NaCl have the same molarity, we will determine the effect of solute and ionic bonding between compound on melting point. Since common salt (NaCl) is made up of stronger ionic bonds, it will have higher melting point than sugar.

The increasing order of their melting point wile be 0.1M sugar < 0.1 M NaCl < 0.08M CaCl2 < 0.04 M Na2SO4​

ANSWER

Lead (IV) Arsenate

STEP-BY-STEP EXPLANATION:

The compound consists of two elements which are; Lead and Arsenic, and oxygen

Combination off oxygen and Arsenic gives Arsenate

The name of the compound is Lead (VI) Arsenate

Mass of titanium having density 4.540 g/cm³) is 565.2g

What are significant figures?

Rules for calculating significant figures:

ex: 1.457 + 83.2 = 84.657 , rounds to 84.7

ex: 4.36 * 0.00013 = 0.0005668 , round to 0.00057

here, density = mass/ volume

mass = density * volume

= 4.540 * 124.50

= 565.23

Value of density has 4 significant figures and value of volume has 5 significant figures. so we choose density, since it has least significant figures and round to 4 digits.

We get, 565.2g as the mass of titanium

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Answer:

0.089 M

Explanation:

M1V1=M2V2

Total volume = 150 ml + 85 ml = 235ml

0.157(.085 L) = M2(.235L)

M2 = 0.05678723404 or 0.057 M

Explanation:

The 3 elements are As, Ga, and Se.

Please, look at the next picture:

According to the 2 pictures above, the right arrangement will be:

Ga < As < Se

Ga has the lowest ionization energy and Se has the highest ionization energy.

Answer: Ga < As < Se

According to the given picture, in the molecules there are single bonds, double bonds, carbon atoms and hydrogen atoms. It means that the correct answer is A.

Answer

20 mol/L

Explanation

Given:

Mass of H₂SO₄ = 98 g

Volume = 0.05 L

From the Periodic Table; Atomic mass (H = 1.0 g, O = 16.0 g, S = 32.0 g)

What to find:

Molarity of the solution.

Step-by-step solution

Step 1: Convert the given mass of 98 g to mole.

The formula to determine the mole is given by:

Molar mass of H₂SO₄ = (2 x 1.0 g) + 32.0 g + (4 x 16.0 g) = 98 g/mol

So mole is

Step 2: Determine the molarity

The molarity formula is given by: