A student mixes 20.0gof white KCl crystals with distilled water in a beaker. After the mixture was stirred, no crystals are visible and the solution is clear. After several days, all of the water evaporates and white crystals are found in the beaker. Which of following pieces of experimental evidence would best help the student to confirm that a new compound had not been made and that only a physical change occurred?
a- The solution does not change color after stirring.
b- The KCl crystals are no longer visible after mixing with water.
c- There is a temperature change in the solution during the dissolving process.
d- After the water has evaporated, the white crystals in the beaker have a mass of 20.0g

Answer:

s=d/t. d=540 t=9h

540÷90=6 km/h

Answer:

I think 1, 4, and 5 are the answers to this question. I am not sure about 4 though.

Explanation:

You have to have a power source (1), you also have to have a way to get that power somewhere else (5), and the reason for 4 would be that the power has to come back through the power source to remain working.

Answer is C

A synthesis reaction looks like this:

A+ B → AB

A spectrum is a  pattern is unique to a substance and can be used identify it.

According to Max Plank, energy occurs in packets called quanta. Hence, energy is not continuous but takes on discrete values which are integer multiples of a fundamental amount.

Again, when a substance is given light energy, a characteristic fingerprint is obtained. This pattern is unique to the substance that has it. These characteristics “fingerprints” are called spectrums.

Learn more: https://brainly.com/question/6284546

Answer:

Conduction is the transfer of heat between substances that are in direct contact with each other. Explanation:The better the conductor, the more rapidly heat will be transferred. Metal is a good conduction of heat. Conduction occurs when a substance is heated, particles will gain more energy, and vibrate more.

Answer:

C) creating a relationship between mass and volume

g/L

g or gram is mass

L or Litres is for volume

Answer:

there aren't any choices on the question so here's the closest i can give. A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure

Answer:

.

In case of a shortage in petroleum and natural gas, a company should find a way to make nylon without using natural resources.

Nylon is a very important material used in numerous applications. As a result of this, the demand for nylon as a raw material has genuinely been on the high side ever since.

However, nylon production depends on petroleum and natural gas. It is possible that there could be a shortage of these resources since they are obtained from the environment. In such cases, a company should  find a way to make nylon without using natural resources.

Learn more about polymers: https://brainly.com/question/17555341

Answer:

identify a different natural resource that nylon could be made from

Explanation:

I just did this question

Question

What does it mean to optimize a solution?

To find out best possible solution for a given problem within the given constraint is generally termed as optimization

How are solution optimize ?

To solve an optimization problem, begin by drawing a picture and introducing variables. Find an equation relating the variables. Find a function of one variable to describe the quantity that is to be minimized or maximized. Look for critical points to locate local extrema.

I believe the answer would be titanium. Good luck on your assignment and have a happy christmas :)

Answer:

Electronegativity is defined as the tendency of an atom participating in a covalent bond to attract the bonding electrons

Explanation:

Electronegativity increases and you go up and to the right, making fluorine the most electronegative element.

Answer:

3 is correct answer I think

Explanation:

Labor unions arose in the nineteenth century as increasing numbers of Americans took jobs in factories, mines, and mills in the growing industrial economy.

The Knights of Labor, founded in 1869, was the first major labor organization in the United States. The Knights organized unskilled and skilled workers, campaigned for an eight hour workday, and aspired to form a cooperative society in which laborers owned the industries in which they worked.

The Knights’ membership collapsed following the 1886 Haymarket Square riot in Chicago. By 1886 the American Federation of Labor (AFL), an alliance of skilled workers’ trade unions, was growing.

Answer:

I think its b part or none of above

Answer:

It is called ions

Explanation:

Answer:

nonmetals. it's one of them

Answer:

A. cycas

1. it is thick and scaly

2. it grow relatively slowly and have a large, terminal rosette of leaves.

B. bamboo

1. it is very durable

2. it is both flexible and elastic

C. lemna

1. it grows as simple free-floating thalli on or just beneath the water surface

2. it are small, not exceeding 5 mm in length

D. paddy

1. it is variety purity

2. it degree of purity

E. sugarcane

1. it is bear long sword-shaped leaves

2. it's stalks are composed of many segments, and in each joint there is a bud

Answer:

I hate chemistry good luck alice

An element symbol is a one- or two-letter abbreviation for a chemical element name. When a symbol consists of two letters, the first letter is always capitalized, while the second letter is lowercase. Element symbols also can refer to alchemy symbols for the elements or to the symbols used to describe isotopes.

Study hard!

Answer:

100 m/ s²

Explanation:

Newton's Second Law of Motion:

[tex] \boxed{ \mathsf{force = mass \times acceleration}}[/tex]

___________________

In the question:

Note that the quantities here must be in their SI units.

SI unit of Force is Newton(N).

SI unit of mass is kilogram(kg)

Force is already in it's SI unit, while mass isn't.

Converting mass from grams to kilograms:

1000 g = 1 kg

=> 1 g = 1/ 1000 kg

=> 50 g = 50/ 1000 kg

= 1/ 20 kg

___________________

Calculating acceleration:

[tex] \mathsf{5 = \frac{1}{20} \times acceleration }[/tex]

multiplying both sides by 20:

[tex] \implies \mathsf{5 \times 20= (\frac{1}{20} \times 20)\times acceleration }[/tex]

20 on the RHS gets canceled, for it's present on the numerator as well as the denominator.

[tex] \implies \mathsf{100= acceleration }[/tex]

So, here, we got acceleration = 100 m/s².

Since, the other quantities used in the formula are in their SI units, acceleration must be in it's SI unit as well.

The SI unit of acceleration is m/s²

___________________

Answer:

[tex] \boxed{ \mathsf{100 \:m/s^2= acceleration }}[/tex]

Answer:

(Physical or Chemical) properties of a substance can easily be observed. … (Physical or Chemical) properties can be used to identify substances. physical property. Oxygen is odorless and colorless.

Explanation:

Answer:

Green

Explanation:

Ammonia turns the cabbage juice into a blue/green color because it is a base, a material that tastes bitter and makes an acid neutral.

Answer:

green

Explanation:

I did the experiment

Answer:

In a pure metal, the force needed to make the layers slide over each other is small. This explains why many pure metals are soft. ... The smaller or bigger atoms distort the layers of atoms in the pure metal. This means that a greater force is required for the layers to slide over each other.

Explanation:

In a pure metal, the force needed to make the layers slide over each other is small. This explains why many pure metals are soft. ... The smaller or bigger atoms distort the layers of atoms in the pure metal.

Answer:

Nickel(III) Sulfate Ni2(SO4)3 Molecular Weight -- EndMemo.

Explanation:

this will explain everything

Answer:

are you interested in tun

Answer: 2.1 minutes

Explanation: Based on the graph, what is the approximate half-life of the reaction shown below

Answer:

Calcium

Explanation:

I just checked the periodic table! This is right checked twice, I hope this helped first time answering a question. Good luck!

Answer:

D. Electrons are gained and lost

Explanation:

When electrons are gain and lost, redox reaction takes place. In redox reaction, reduction and oxidation tales place simultaneously. Therefore, option D is correct.

Redox reactions include a change in the oxidation state of the substrate. When electrons are lost or the oxidation state increases, it is called oxidation; when they are gained or the oxidation state decreases, it is called reduction.

Redox reactions are those in which there is a change in the oxidation number, with both an increase and a drop in number. The reaction called non-redox if this does not take place.

Oxidation and reduction always occur jointly because any loss of electrons by one substance must be followed by a gain of electrons by another. Therefore, oxidation-reduction processes or simply redox reactions are other names for electron-transfer events.

Thus, option D is correct.

To learn more about redox reaction, follow the link;

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