10) Identify the substance as an acid or a base and put an "X" in the box.
l

Answer:

Explanation: 2 C19H34O2(l) + 53 O2(g) ==> 38 CO2(g) + 34 H2O(l) ... balanced equation

∆Hcombustion

∆H = ∑∆Hf products - ∑∆Hf reactants

∆H = [(38 x -393.5) + (34 x -285.8)] - (2 x -645.7) = (-14,953 + -9717) - (-1291)

∆H = -24,670 + 1291

∆H = 25,961 kJ

(be sure to check the math)

According to the stoichiometry, 4.85 g of propane is required to produce 14.7 g carbon dioxide.

It is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.

Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.

In the given problem as per balanced equation of combustion of propane 2 molecules of propane produce  8 molecules of carbon dioxide.That is, 116.24 g of propane produces 352.08 g of carbon dioxide.

∴14.7 g of carbon dioxide is produced by, 14.7×116.24/352.08=4.85 g of propane.

Thus, 4.85 g of propane is required to produce 14.7 g of carbon dioxide.

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Green column - Alkaline earth metals

Red column - Alkali metals

Purple column - Lanthanides and actinides

Blue column - Transition metals

The red block are made up of group 1 elements and these elements are known as Alkali metals.

The green column are the group 2 elements in the periodic table and are known as the Alkali earth metals.

For the blue columns, they are element from group 3 to 10 and they are known as the transition metals.

For the purple column, they are Lanthanides and actinides

This element is nonmetal and appears in the periodic table.

The number that represents the position of the elements is called, the atomic number, it also represents the number of protons = numbers of electrons an atom has.

Answer: D. the atomic number

A student finds two green powders that look the same he wants to figure out if the two powders are the same or different substances then mix the two green powders together and then test the properties

A powder is a dry bulk solid composed of many very fine particles that may flow freely when shaken or tilted and to figure out unknown two mixture powder are same or different then student want to mix the two green powders together and then test the properties because of properties student the two unknown powder are to be determined

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Ethylmethylamine is a secondary amine, that has one ethyl group attached to the amine group and one methyl group, which is a also attached to the amine group.

It is represented by:

Nevertheless it can be represented by CH3CH2NHCH3.

It means that the correct answer is c. Both.

The volume of 0.875 mol/dm³ NaOH solution needed to make up a 100.0 ml of a diluted solution with a concentration of 0.235 mol/dm³ NaOH is 73.15 mL.

Given that :

molarity M1 = 0.875 mol/ dm³

M2 = 0.235 mol/ dm³

volume V2 = 100mL

using the formula , we get

M1 V1 = M2 V2

substituting the values in the formula we get :

0.875 × V1 = 0.235 × 100 mL

V1 = 26.857 mL

the volume added = V2 - V1 = 100 mL - 26.85 = 73.15

Thus, The volume of 0.875 mol/dm³ NaOH solution needed to make up a 100.0 ml of a diluted solution with a concentration of 0.235 mol/dm³ NaOH is 73.15 mL.

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Answer:

C = 9 mol

Explanation:

Reaction: A + 2B ---> C

We want to find the moles of C.

Given: moles of A = 9 mol.

To solve this problem we will need to use stoichiometry.

A is the limiting reagent because it has a coefficient of 1 and B has a coefficient of 2.

The molar ratio between A and C is 1:1 therefore for every 9 moles of A that react, 9 moles of C will be produced.

Answer

wiring

Explanation

Ancient humans did make jewelry, weapons and tools by smoltering ore, however, they did not make wires, hence there was no electricity in many mnay years ago.

Answer:

0.9933

(Text Text Text)

The proton acceptor (base) in this following reaction is  H₃0⁺

Here given reaction is

HCI + H₂O  → CH + H₃O⁺

A proton is a subatomic particle found in the nucleus of every atom so in that reaction H₃0⁺ is the  proton acceptor because protonic acid is the proton donor H⁺ so H₃0⁺ must be bronsted acid and OH⁻ because it accept the proton is a therefore a bronsted base and a lewis acid is by definition an electron pair acceptor and a lewis base is an electron pair donor

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Answer:

d. Nickel

Explanation:

The atomic radius is a periodic property, that is, we can see how it varies in the Periodic Table of Elements.

Atomic radius increases by a column (group) from top to bottom, and increases by a row (period) from right to left.

We can see the variation of atomic radius and the location of the given atoms in the following drawing:

Since K (potassium), Ca (calcium), Co (cobalt) and Ni (nickel) are located in the same row (period), to identify which one has the smallest atomic radius, we have to analyze the increase in horizontal atomic radius.

So, the Ni atom has the smallest atomic radius (because it is located more to the right compared to the other atoms in the same row) and K atom has the largest atomic radius.

The formula for calculating the amount of heat energy absorbed is given as:

Given the following

• mass m = 50.0g

• Heat energy Q = 7490 Joules

• change in temperature = 80 -10= 70 degrees celsius

Substitute

Hence the specific heat capacity of methanol is 2.14J/gC

Answer:

89.58 moles of MnO3 are produced.

Explanation:

1st) From the balanced reaction we know that the relation between O2 and MnO3 is that 3 moles of O2 produces 2 moles of MnO3.

2nd) To build the equation, we must build a path from the given value of 4.30kg of O2 to moles of MnO3. So, it is important to figure out the relations that we need to build the equation.

The order to build the equation is:

• Start with, the given value of ,4.30kg of O2,.

• We need to convert kg to grams, so we need the realtion between kg and g: ,1kg=1000g,.

• To convert the grams of oxygen to moles, we need to use the molar mass of O2: ,32g/1mol,.

• We need to use the relation between O2 and MnO3 from the balanced equation: ,3 moles of O2, produces, 2 moles of MnO3,.

So, 89.58 moles of MnO3 are produced.

Answer

acids and bases are both corrosive furthermore both will conduct electricity depending on the strength of the acid or base

C is the correct option

ANSWER

Volume of the gas 5.3L

EXPLANATION;

Given that

The pressure of the chlorine gas is 688 torr

The temperature of the chlorine gas is 36 degrees Celcius

The mass of NaCl is 22 grams

Follow the steps below to find the volume of chlorine gas

Step 1; Write a balanced equation for the reaction

In the above reaction, 2 moles of Na react with 1 mole of chlorine to form 2 moles of NaCl

Step 2; Find the number of moles of NaCl using the below formula

Recall, that the molar mass of NaCl is 58.44 g/mol

Step 3; Find the number of moles of Cl2 using a stoichiometry ratio

Let x represents the number of moles of Cl2

The number of moles of Cl2 is 0.188 mol

Step 4; Find the volume of the gas using the ideal gas equation

Convert the temperature to degree kelvin

Step 5; Find the volume of the gas

Therefore, volume of the gas 5.3L

To find out how many significant numbers there are in a number we can rely on a few rules:

1. Non-zero digits are always significant

2. Any zeros between non-zero digits are significant

3. Final zeros or trailing zeros are significant if they come after the non-zero numbers in a decimal number situation

Example: .500 and .632000

In this question, we have:

0.0016/0.849 = 0.0019, this is the correct value with the correct number of significant figures

Step 1

Data provided:

The reaction: 4Al + 3O2 => 2Al2O3 (balanced)

The limiting reactant Al (it is said that Al reacts completely)

Mass of Al = 42.6 g

The actual yield = 57.8 g Al2O3

-----------------------

Step 2

Data needed: the molar mass of Al (26.9 g/mol) and Al2O3 (101.9 g/mol)

The theoretical yield:

4 x 26.9 g Al ------- 2 x 101.9 g Al2O3

42.6 g Al ------- X = 80.7 g Al2O3 = theoretical yield

---------------------

Step 3

% yield = (actual yield/theoretical yield) x 100 = (57.8 g/80.7 g) x 100 = 71.6 %

(this is the closest value for one of the options, 71.8 %)

Answer: 71.8 %

A legend of the North star goes as follows:

The North star is a star that sits directly above the North pole of the earth. It is also known as Polaris.

The North star is especially significant in that the North star is an ever-present star in the skies. It neither rises nor sets unlike other stars in the skies.

Because of this special feature of the North star, it serves as a guiding beacon in the skies for travelers. Also, several legends have been told about the North star.

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The initial temperature of the argon is 2678 K

Given that,

Initial volume (V1) = 4.95 L

Initial pressure (P1) = 0.92 atm

Final temperature (T2) = 30 C = 303.15 K

Final volume (V2) = 5.7 L

Final pressure (P2) = 0.092 atm

We need to find the Initial temperature of the argon represented as T1

We Know that, In ideal gas law: PV = nRT

It can be written as, P1V1 / T1 = P2V2 / T2

(0.92 * 4.95) / T1 = (0.092 * 5.7) / 303.15

4.554 / T1 = 0.5244 / 303.15

4.554 / T1 = 0.0017

T1 = 4.554 / 0.0017

T1 = 2678 K

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Step 1 - Understanding percentual concentration

To express the concentration of a substance as a percentual concentration, we just need to divide its mass by the total mass:

Step 2 - Calculating the concentration in the pill

We want to calculate the concentration of Mg in the pill. Therefore, we'll divide its mass by the total mass of the pill:

Answer: the concentration of Mg in the pill is 6.8%

Answer:

Explanation:

As the cell has a copper strip like the anode and a coin or nail (we can consider this like it is nickel) like the cathode, we can write both half-reactions:

• Copper half-reaction,:

In the copper anode, the oxidation reaction takes place. This is the positive terminal.

• Nickel half-reaction,:

In the nickel cathode, the reduction reaction takes place. This is the negative terminal.

The direction of the electron flow always go from the anode to the cathode.

Answer:

A

Explanation:

it is easy and doesn't take a long time

According to the given statement one mole of potassium has a mass of 39.1 g.

Each element's atomic weight is listed in a periodic table along with how many grams (or an Avogadro number) are needed to make one mole of atoms. Since potassium has an atomic weight of 39.0983 g/mole, a mole of potassium weighs 39.1 g.

Avogadro's number, which is equal to 6.02214076 * 10²³, is the quantity of units in one mole of any material (defined as its molecular weight in grams). Depending on the substance and the nature of the reaction, the units could be electrons, atoms, ions, or molecules.

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ANSWER

The pressure of the gas is 281.25 mmHg

EXPLANATION

Given that;

The initial pressure of the gas is 75 mmHg

The intial temperature of the gas is 80K

The final temperature of the gas is 27 degrees Celcius

Follow the steps below to find the final pressure of the gas

Step 1; Convert the final temperature to degrees kelvin

Step 2; Apply the Gay Lussac's law

Step 1

Density is defined as:

D = mass of the platinum brick/volume of the platinum brick

D = m/V

------------------

Step 2

Information provided:

D = 21.45 g/mL

V = 150.0 mL

m = unknown

Price per grams of Pt = 31.86 $/g of Pt

Symbol for platinum = Pt (please, look at the periodic table)

-----------------

Step 3

How much should the brick weigh if it’s is really platinum?

From D = m/V

=> D x V = m

=> 21.45 g/mL x 150.0 mL = 3218 g approx.

------

And how much money?

3218 g of Pt x 31.86 $/g of Pt = $99,660 approx.

Answer:

3218 g

$99,660

General nucleus and electron attraction explained

We can say this:

The net positive charge from the nucleus (remember that protons are in the nucleus) that an electron can feel attraction from, is the effective nuclear charge. The core electrons (electrons are on shells around the nucleus) are said to shield the valence electrons from the full attractive forces of the pro

In this question, we have a reaction between silver nitrate and potassium chloride, which will have the following chemical formula and also the following product:

AgNO3 (aq) + KCl (aq) --> AgCl (s) + KNO3 (aq)

Now we need to identify the ions that are components of the precipitate that was formed in this reaction

A precipitate is a product of a reaction that is not soluble in water in the conditions given in the reaction, therefore the precipitate will be a solid product of the reaction. The solid of the reaction is AgCl, therefore this is the precipitate

Now the ions that compose AgCl are Ag+ and Cl-, the answer will be the 3rd option

The answer is -2219.9 kJ/mol