All categories

2 years ago

Can matter be created or destroyed? Yes or No

Chemistry

2 answers:

Stells [14]2 years ago

6 0

Answer:

none is created or destroyed. This concept is called the Law of Conservation of Mass.

anzhelika [568]2 years ago

5 0

Answer:

Explanation:

The same amount of matter is present before and after chemical and physical changes. Matter cannot be created or destroyed

You might be interested in

A company's managers ask, "Should we increase the size of our Bluetooth wireless speaker and sell it at a higher cost?" Never pr

Ivahew [28]

Complete Question

Identify whether the following activity on the table shown on the first uploaded image are examples of business level or corporate level strategy

Answer:

The solution to this is shown on the second uploaded image

Explanation:

The explanation is shown on the third and fourth uploaded image

5 0

3 years ago

The reaction 2KClO3(s) --> 2KCl(s) + 3O2(g) is a(n)

julia-pushkina [17]

Answer:

decomposition reaction.

Explanation:

It is a decomposition reaction as potassium chlorate compound breaks to form potassium chloride and oxygen. This reaction requires heat as source of energy to break down the compound so it is endothermic in nature.

8 0

3 years ago

A compound contains 6.0 g of carbon and 1.0 g of hydrogen and has a molar mass of 42.0 g/mol.

makvit [3.9K]

Answer:

%C = 85.71 wt%; %H = 14.29 wt%; Empirical Formula => CH₂; Molecular Formula => C₃H₆

Explanation:

%Composition

Wt C = 6 g

Wt H = 1 g

TTL Wt = 6g + 1g = 7g

%C per 100wt = (6/7)100% = 85.71 wt%

%H per 100wt = (1/7)100% = 14.29 wt % or, %H = 100% - %C = 100% - 85.71% = 14.29 wt% H

What you should know when working empirical formula and molecular formula problems.

Empirical Formula=> smallest whole number ratio of elements in a compound

Molecular Formula => actual whole number ratio of elements in a compound

Empirical Formula Weight x Whole Number Multiple = Molecular Weight

From elemental %composition values given (or, determined as above), the empirical formula type problem follows a very repeatable pattern. This is ...

% => grams => moles => ratio => reduce ratio => empirical ratio

for determination of molecular formula one uses the empirical weight - molecular weight relationship above to determine the whole number multiple for the molecular ratios.

Caution => In some 'textbook' empirical formula problems, the empirical ratio may contain a fraction in the amount of 0.25, 0.50 or 0.75. If such an issue arises, multiply all empirical ratio numbers containing 0.25 and/or 0.75 by '4' to get the empirical ratio and multiply all empirical ration numbers containing 0.50 by '2' to get the final empirical ratio.

This problem:

Empirical Formula:

Using the % per 100wt values in part 'a' ...

% => grams => moles

%C => 85.71% => 85.71 g* / 100 g Cpd => (85.71 / 12) = 7.14 mol C

%H => 14.29% => 14.29 g / 100 g Cpd => (14.29 / 1) = 14.29 mol H

=> Set up mole Ratio and Reduce to Empirical Ratio:

mole ratio C:H => 7.14 : 14.29

To reduce mole values to the smallest whole number ratio, divide all mole values by the smaller mole value of the set.

=> 7.14/7.14 : 14.29/7.14 => Empirical Ration=> 1 : 2

∴ Empirical Formula => CH₂

Molecular Formula:

(Empirical Formula Wt)·N = Molecular Wt => N = Molecular Wt / Empirical Wt

N = 42 / 14 = 3 => multiply subscripts of empirical formula by '3'.

Therefore, the molecular formula is C₃H₆

3 0

3 years ago

Some activities that are generally considered to be work are not called work by scientists. Explain why.

Flura [38]

Answer:

Certain things we think of as hard work, such as writing an exam or carrying a heavy load on level ground, are not work as defined by a scientist. The scientific definition of work reveals its relationship to energy—whenever work is done, energy is transferred.

For work, in the scientific sense, to be done, a force must be exerted and there must be motion or displacement in the direction of the force.

5 0

2 years ago

Which statements describe phase changes? Check all that apply. Particles in a liquid need to move more slowly in order to freeze

Kipish [7]

Answer: Statements (A), and (C) are correct.

Explanation:

The statements that are true are as follows.

Particles in a liquid need to move more slowly in order to freeze.

When a liquid freezes the molecules get attracted towards each other. This attraction of particles occurs slowly. Hence, this statement is true.

Attractive forces between the particles in a liquid are broken when a liquid boils.

When temperature is raised, the molecules in a liquid gains kinetic energy and start to move quickly in random directions. As a result, liquid state changes to gaseous state. Hence, this statement is true.

If the attractive force between gas molecules have to be increased, they should be moving slower instead because moving faster does not help attracting molecules together.

Hence, the statement particles in gas move fast enough to make more attractive forces when the gas condenses is not true.

4 0

3 years ago

Read 2 more answers