Which laboratory activity involves a chemical change?

Answer:

(D) greater than the energy stored in the bonds of the products.

Explanation:

Exothermic reaction refer to those reactions in which energy is released to the surrounding, unlike endothermic reactions where energy is absorbed from the surroundings.

In exothermic reactions, the change in energy; ΔH less than zero. That is, they are negative.

ΔH = H (products) - H (reactants)

For ΔH to have a negative value, it means the energy of reactant must be greater than the energy of products.

This means the correct option is;

(D) greater than the energy stored in the bonds of the products.

In an exothermic reaction the energy of the reactants bonds has been higher than the energy of the product bonds. Thus, option D is correct.

The exothermic reaction has been given as the chemical reaction in which there has been the liberation of energy by the reactants in the process of formation of products.

The energy change in the reaction has been a negative value. In the process of product formation, the energy of the system has been conserved. It stated that the energy of the reactant has been equivalent to the energy of the product and the liberated energy.

With the product being consisted of less energy, the energy stored by the chemical bonds in the reactants has been higher than the energy stored by the product. Thus, option D is correct.

For more information about the exothermic reaction, refer to the link:

https://brainly.com/question/14969584

Explanation:

On a hot day, the speed at which we perceived the smell of the perfume will be much faster due to the increase in kinetic energy of the perfume molecules.

Based on the kinetic molecular theory of gases, the average motion of particles increases as their thermal energy increases. On a hot day, the heat causes an increase in the average kinetic energy of the particles and the perfume molecules moves faster.

On a cold day, the molecules are slower and the rate at which we perceive the perfume smell is very slow. The particles will diffuse less faster and this is due to the low average kinetic energy they possess.

Answer:

The percent natural abundance is 27.95% for the heavier isotope (86.901 amu)

Explanation:

The atomic mass of Rubidium (Rb) is 85.468.

To find the percent natural abundance, first we need to use the following equation:

84.912x + 86.901(1-x) = 85.468

x represents the percent natural abundance, in basic decimal form

In order to find x, we will use the distributive property, combine like terms and then move the constant to the other side to get x.

We are first finding the percent natural abundance of the first isotope to make this easier for us.

84.912x + 86.901(1-x) = 85.468

-> 84.912x + 86.901- 86.901x = 85.468

-> 86.901 - 1.989x  = 85.458      (like terms were combined)

-> Subtract both sides by 86.901

-> Divide both sides by-1.989x

x = 0.720462544

Now turn this into a percent by multiplying by 100.

--> 72.05% for the first isotope (the one that contains 84.912 amu)

To find the natural abundance of the other isotope (the denser, heavier isotope), you could just subtract 72.05 from 100 to save time, but the usually desired way (the way that your teacher would probably want you to do) is down below:

We plug this decimal for the x-value into the parentheses from earlier:

(1 -x) ---> ( 1 - 0.720462544 ) = 0.279537456

Now we just need to convert this to a percent by multiplying by 100

0.279537456 * 100 = 27.95% of the heavier isotope (86.901 amu)

Answer:

It covers changes to the position of equilibrium if you change concentration, pressure or temperature. ... If a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change

Explanation:

Answer:

a.

Turn paper Blue - these are alkaline/ base substances.

Turn paper Red - these substances are acidic in nature.

b. i. A wasp sting - Lemon juice

ii. A bee sting - Toothpaste

iii. A wasp sting is alkaline which means that running an acidic substance like lemon or lemon juice on it should neutralize it.

A bee sting is acidic so an alkaline substance such as toothpaste should neutralize it as well.

Answer:

It contain double Bond.

Explanation:

To determine weather the bond is double or triple simply check the electron involved in mutual sharing of an electron if 2 electron takes parts it said to be double or if 3 it said to be triple.

Answer:

3.2 micro gram

Explanation:

because

1kg=1000g

32×10^-10kg=?

=3.2×10^-6g

1g=10^-6micro gram

3.2×10^-6g=?

=3.2 micro gram.

where g- gram

kg- kilogram

Answer:

The Answer is 2.1

Hope this helps!

a. 1,4332 g

b. 7.54~g

Given

Reaction

MgCl2 (s) + 2 AgNO3 (aq) → Mg(NO3)2 (aq) + 2 AgCl (s)

20 cm of 2.5 mol/dm^3 of MgCl2

20 cm of 2.5 g/dm^3 of MgCl2

Required

the mass of silver chloride - AgCl

Solution

a. mol MgCl2 :

[tex]\tt 20~cm^3=20\times 10^{-3}~dm^3\\\\mol=M\times V\\\\mol=2.5~mol/dm^3\times 20\times 10^{-3}DM^3=0.05[/tex]

From equation, mol AgCl = 2 x mol MgCl2=2 x 0.05=0.1

mass AgCl(MW=143,32 g/mol)= 0.1 x 143,32=1,4332 g

b. mol MgCl2 (MW=95.211 /mol):

[tex]\tt mol=M\times V\\\\mol=\dfrac{2.5~g/dm^3}{95,211 g/mol}=0.0263~mol/dm^3[/tex]

From equation, mol AgCl = 2 x mol MgCl2=2 x 0.0263=0.0526

mass AgCl(MW=143,32 g/mol)= 0.0526 x 143,32=7.54~g

Answer:

Ways to reduce friction are by using oil, rollers from roller blades or other stuff that has a roller in or on it, wax, and grease.

Explanation:

Oil can reduce friction because it is used as a lubricant to reduce friction so moving surfaces slide smoothly over one another the same thing with wax and grease. The rollers are because they reduce friction by reducing contact between moving surfaces.

Answer:

b the heavier ball has more kinetic energy than the lighter ball because it has more mass

Answer:

183 K

General Formulas and Concepts:

Chemistry - Gas Laws

Combined Gas Law: PV = nRT

Explanation:

Step 1: Define

10.0 L

3.00 mol H₂

4.50 atm

Step 2: Find Temperature

Step 3: Check

Round to the nearest whole number.

182.704 K ≈ 183 K

Answer:

The answer is B

Answer:

a) The heat energy absorbed to heat the solid is approximately 58.8 kJ

b) The heat required to melt the solid is approximately 3.93 kJ

c) The heat required to heat the liquid is approximately 29.2 kJ

d) The total amount of energy, absorbed in the entire process is approximately 92 kJ

Explanation:

a) The given parameters are;

The mass of the substance = 488.3 grams

The molar mass of the sample = 92.41g/mol

The temperature change of the substance = -23.1°C to 51.8 °C

The heat capacity of the solid substance = 2.96 J/(g·°C)

The heat capacity of the liquid substance = 1.75 J/(g·°C)

ΔHfus = 8.04 kJ/mol

Taking the melting point temperature of the solid as Tfinal = 17.6 °C, we have;

The heat energy absorbed to heat the solid, Q₁ = 488.3 × 2.96 × (17.6 - (-23.1)) = 58826.4776 J ≈ 58.8 kJ

b) The heat required to melt the solid, Q₂ = ΔHfus × m = 8.04 × 488.3 = 3925.932 J ≈ 3.93 kJ

c) The heat required to heat the liquid, Q₃ = Mass × The specific heat capacity of the liquid × The change in temperature

Therefore;

Q₃ = 488.3 × 1.75 × (51.8 - 17.6) = 29224.755 J ≈ 29.2 kJ

d) The total amount of energy, absorbed in the entire process, ΔQ, is given as follows;

ΔQ = Q₁ + Q₂ + Q₃ = 58826.4776 J + 3925.932 J + 29224.755 J = 91,977.1646 J ≈ 92 kJ

Answer:

1.40 atm

Explanation:

P1V1 = P2V2

P2= P1* V1/V2

P1=649.0mmHg

V1= 32.0mL

V2= 19.5mL

P2=649.0mmHg*32.0ml/19.5ml=

1065.03mmHg

To get mmHg to atm. The formula is 1atm/760mmHg

Use the answer you got in mmHg to convert into (atm), If you were asked

1065.03mmHg*(1atm/760mmHg)= 1.40atm

Answer:

Sulfur

Explanation:

it has 16 proton and 2- charges

Answer:

D

Explanation:

We already know oxygen's mass is 15.99 amu, and the mass of a mole is 6.02 * 10^23, so just multiply the two together for 15.99 * (6.02 * 10^23) g.

15.99 x (6.02x[tex]10^{23}[/tex])g mass does 1 mol of O2 gas have. Hence, option D is correct.

A mole is defined as 6.02214076 × [tex]10^{23}[/tex]of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.

We already know oxygen's mass is 15.99 amu, and the mass of a mole is 6.02 x [tex]10^{23}[/tex], so just multiply the two together for 15.99 x (6.02x[tex]10^{23}[/tex])g.

Hence, option D is correct.

Learn more about moles here:

https://brainly.com/question/8455949

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Answer:

5SiO2 + 2CaC2 = 5Si + 2CaO + 4CO2

Explanation:

balancing equations is a lot of trial and error. My strategy to approaching this equation was to get the O's balanced. After trying several combonations I found that I needed 10 O's on each side of the equation for the other elements to match up. After I balanced the O's, I balanced my C's to 4 on each side. Then I balanced my Ca's to have 2 on each side. And last but not least I balanced my Si to have 5 on each side.

Answer:

Atomic radius is the distance from the atom's nucleus to the outer edge of the electron cloud. In general, atomic radius decreases across a period and increases down a group. Across a period, effective nuclear charge increases as electron shielding remains constant.

Explanation:

Answer:

C.

Explanation:

Crossbreeding is the correct answer.

Answer:

C. Crossbreeding

Explanation:

Answer:

Superscript 235 subscript 92 upper U plus superscript 1 subscript 0 n right arrow superscript 90 subscript 38 upper S r plus superscript 143 subscript 54 upper X e plus 3 superscript 1 subscript 0 n.

Explanation:

B

Answer:

b

Explanation:

got it right on test

Answer:

a) 1.65 bar

b) 4.2 L

Explanation:

From Boyle's law(since temperature is constant);

P1V1= P2V2

P2 = P1V1/V2

V1 = 110 ml

T1=  33 + 273 =306 K

P1 = 2.4 bar

V2 = 160 ml

T2 = 33 + 273 = 306

P2 =?

P2 = 2.4 * 110/160

P2 = 1.65 bar

2)

T1 = 26.2 + 273 = 299.2 K

V1 = 4L

T2 = 38.1 + 273 = 311.1

V2 =?

From Charles's law;

V1/T1 = V2/T2

V1T2 = V2T1

V2 = V1T2/T1

V2 = 4 * 311.1/299.2

V2 = 4.2 L

Answer:

Explanation:

A decomposition reaction occurs when one reactant breaks down into two or more products. This can be represented by the general equation: AB → A + B. Examples of decomposition reactions include the breakdown of hydrogen peroxide to water and oxygen, and the breakdown of water to hydrogen and oxygen.

Answer:

Covalent bond

Explanation: Hydrogen and Oxygen are both non-metals, with a low difference in electronegativity. They will share electrons.

Answer:

In an atom model, the first energy level can hold 2 electrons, the second level can hold 8 electrons, and the third level can hold 18 electrons.

Explanation:

The Electronic Configuration of the elements is the arrangement of all electrons of an element in energy levels and sub-levels (orbitals).  

There are 7 energy levels, numbered from 1 to 7, and in which electrons are distributed, logically in order according to their energy level. Electrons with less energy will be spinning at level 1. Each level is divided into sub-levels. These sub-levels into which each level is divided can be up to 4. These 4 sub-levels are called: s, p, d, f. In the sub-level s there can only be a maximum of 2 electrons, in p there can be a maximum of 6 electrons, in the sub-level d 10 electrons and finally in the sub-level f there can be a maximum of 14 electrons.

In level 1 there is only one sub-level, which will be the s. In level 2 there are 2 sub-levels, the s and the p. At level 3 there are 3 sub-levels s, p and d. And at level 4 there are 4 sub-levels, the s, the p, the d and the f.

Then, in an atom model, the first energy level can hold 2 electrons, the second level can hold 8 electrons, and the third level can hold 18 electrons.

Answer:

meter

have a nice holiday

Answer:

The Meter

Explanation:

In the metric system, the meter is the standard measurement of length.

Hope it helped!

Answer:

Water, a substance composed of the chemical elements hydrogen and oxygen and existing in gaseous, liquid, and solid states. It is one of the most plentiful and essential of compounds. A tasteless and odourless liquid at room temperature, it has the important ability to dissolve many other substances.

Explanation:

Answer/Explanation:

Water is a colorless and tasteless liquid that makes up an organism or body of any sort.

The meaning of the (holy)water is the spirit that flows in each person that will keep their hearts satisfied. Jesus used this term when talking to a Samaritan at a well. Water is also the source of the living water that springs up into eternal life. When talking about this water, Jesus was referring to himself. For His water(blood) had not yet been poured out and it could not yet cleanse (those who believed in him would be gushing out with the living water).

Answer:

wind is the correct answer