Which of the following are pure substances?
table salt, NaCl
water, H20
Oxygen, 02
elements
compounds
all of the above

Answer:

the dependent variable is the number of bug bites with the spray

Explanation:

The  dependent variable is number of bug bites.

An experiment must involve two variables;

The independent variable is the variable that we have to change consistently. The effect of changing this variable on another variable called the independent variable is monitored.

In this case, the independent variable is the spraying of the arm while the dependent variable is the number of bug bites.

The number of bug bites is the dependent variable because it changes as a result of spraying or not spraying the the arm.

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Answer:

solvent

Explanation:

Answer:

It is produced in nuclear reactors.

Explanation:

Fermium is a synthetic element and is not found naturally.

Answer:

3.2 x 10^3

Explanation:

I answered this question on my assignment just not and got it right.

3.2 mg is equivalent to 3.2 × 10³ μg.

In order to convert 3.2 mg to μg, we need to consider 2 conversion factors:

3.2 milligrams, expressed in micrograms, is:

[tex]3.2 mg \times \frac{1g}{10^{3}mg } \times \frac{10^{6}\micro g }{1g} = 3.2 \times 10^{3} \micro g[/tex]

3.2 mg is equivalent to 3.2 × 10³ μg.

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Answer:

Chemistry is the study of matter and the chemical reactions between substances. Chemistry is also the study of matter's composition, structure, and properties. ... Chemistry is sometimes called “the central science,” because it bridges physics with other natural sciences, such as geology and biology.

Explanation:

I hope this helps you!!

Answer:

Explanation:

From the question

mass of Nitrogen = 56 g

Molecular weight = 28 g/mol

To find the number of miles we use the formula

[tex]n = \frac{m}{M} [/tex]

where

n is the number of miles

m is the mass

M is the molecular weight

So we have

[tex]n = \frac{56}{28} [/tex]

We have the answer as

To find the volume we use the formula

V = n × V(dm³)

where

V is the volume

n is the number of miles

V(dm³) is the volume of 1 mole of a gas at STP which is 22.4 dm³

So the volume is

V = 2 × 22.4

We have the answer as

Hope this helps you.

Answer:

Temperature: The rate of evaporation increases with an increase in temperature. Surface area: The rate of evaporation increases with an increase in surface area. Humidity: The amount of water vapour present in the air is called humidity.

may this help you.

hello,

here is your answer:

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Factors affecting evaporation:

⇒ Increase in surface area - if the surface area is increased the rate of evaporation increases.

⇒ Increase in temperature - with increase in temperature, more particles get enough kinetic energy to turn into vapour.

⇒ Decrease in Humidity - air around us can't hold more than a definite amount of water vapour, if amount of water vapour is already high, then rate of evaporation decreases.

⇒ Increase in wind speed - with increase in wind speed, the particles of water vapour move away with the wind, decreasing the amount of vapour in the surrounding atmosphere.

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hope this helped,

:)

Explanation:

They come in different kinds, called elements, but each atom shares certain characteristics in common. All atoms have a dense central core called the atomic nucleus. ... All atoms have at least one proton in their core, and the number of protons determines which kind of element an atom is.

The common feature is that the atoms of all elements consist of electrons, protons, and neutrons.

An atom is a particle of matter that uniquely defines a chemical element.

An atom consists of a central nucleus that is usually surrounded by one or more electrons.

All atoms of an element have the same number of protons, and every element has a different number of protons in its atoms.

For example, all helium atoms have two protons, and no other elements have atoms with two protons.

Learn more about an atom here:

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Answer:

10

Explanation:

The prefixes attached to metric units carry the same meaning for all base units. The metric system is based upon powers of ten, which is convenient because: A measurement in the metric system that is represented by a rational number remains a rational number after metric unit conversion.