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Korvikt [17]
3 years ago
5

Hey please help man...

Chemistry
1 answer:
malfutka [58]3 years ago
4 0

Answer:

1. Cations are positively charged and have less electrons than protons.

2. Anions are negatively charged and have more electrons than protons.

3. Columns on the periodic table are known as groups.

4. The elements in the first group are called alkalis metals and have one valence electron.

Explanation:

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(LO 37,45) A reaction is 75% complete in 45.0 min. How long after its start will the reaction be 50% complete if it is (A) first
seropon [69]

Answer:

A) t = 22.5 min and B) t = 29.94 min

Explanation:

Initial concentration, [A]₀ = 100

Final concentration = 100 -75 = 25

Time = 45 min

A) First order reaction

ln[A] − ln[A]₀ = −kt

Solving for k;

ln[25] − ln[100] = - 45k

-1.386 = -45k

k = 0.0308 min-1

How long after its start will the reaction be 50% complete?

Initial concentration, [A]₀ = 100

Final concentration, [A] = 100 -50 = 50

Time = ?

ln[A] − ln[A]₀ = −kt

Solving for k;

ln[50] − ln[100] = - 0.0308 * t

-0.693 = -0.0308 * t

t = 22.5 min

B) Zero Order

[A] = [A]₀ − kt

Using the values from the initial reaction and solving for k, we have;

25 = 100 - k(45)

-75 = -45k

k = 1.67 M min-1

How long after its start will the reaction be 50% complete?

Initial concentration, [A]₀ = 100

Final concentration, [A] = 100 -50 = 50

Time = ?

[A] = [A]₀ − kt

50 = 100 - (1.67)t

-50 = - 1.67t

t = 29.94 min

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3 years ago
Calculate the speed of sound wave with a frequency of 20hz and a wave length of 3.00m
Marta_Voda [28]
Wavelength is the distance of one frequency wave peak to the other and is most commonly associated with the electromagnetic spectrum.[1] Calculating wavelength is dependent upon the information you are given. If you know the speed and frequency of the wave, you can use the basic formula for wavelength. If you want to determine the wavelength of light given the specific energy of a photon, you would use the energy equation. Calculating wavelength is easy as long as you know the correct equation.
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.Which of the following is an exothermic reaction?
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A melting ice is caused by another element breaking up the atoms and making the move
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Is light made up of atoms and elements?•Explain the relationship between matter, atoms, and elements.. •Distinguish between elem
Mars2501 [29]
<span>Is light made up of atoms and elements?

- </span>Light is made of photons that have no rest mass and exist as an electromagnetic <span>ripple in space-time. So No Light is Not Made Out Of elements and atoms.


</span><span>Explain the relationship between matter, atoms, and elements
</span>
- An element is a basic substance that other things are composed from. Each individual element is made up of tiny, invisible particles called atoms. <span>An atom is the smallest unit of an element that has that element's properties. Both atoms and elements are matter.


</span><span>Distinguish between elements and compounds
</span>
- A compound<span> contains atoms of different </span>elements<span> chemically combined together in a fixed ratio. An </span>element<span> is a pure chemical substance made of same type of atom.</span>Compounds<span> contain different </span>elements<span> in a fixed ratio arranged in a defined manner through chemical bonds.</span><span>


</span><span>Describe molecules, and explain how they are formed
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- <span>A </span>molecule<span> is </span>formed<span> when two or more atoms join together chemically. A compound is a </span>molecule<span> that contains at least two different elements.


</span><span>Interpret and write some common chemical formulas
</span>- CO2: <span>The C indicates that it has one carbon atom.<span>The O2 indicates that it has two oxygen atoms.</span><span>Note that the subscript, in this case 2, is only for the oxygen atom just before it. It does not affect the carbon atom.
- </span></span>2NH3: <span><span>For each NH3 molecule, the N indicates that it has one nitrogen atom and the H3indicates that it has three hydrogen atoms.</span><span>The number 2 in front (called the coefficient) indicates that there are two NH3molecules.</span><span>So, in total, there are two nitrogen atoms and six hydrogen atoms.


</span></span><span>Categorize materials as pure substances or mixtures
</span>- Firstly, a pure substance is matter which cannot be separated into any other kind of matter when using the physical or chemical process. All the particles which make up a pure substance have the same color, taste, composition and texture. In other words, it can be an element or a compound, which consists of only one component with a definite composition, chemical and physical properties.

Secondly, a mixture is a combination of two or more substances which are not united using a chemical procedure. The components that make up a mixture do not exist in fixed proportions, and most of the natural substances that you are familiar with, are mixtures. Examples of mixtures include water, alcohol, oil, and dye.

So what are the distinct differences between these two? With regards to a mixture, it can be physically separated into pure compounds or elements. This is something that is not possible with a pure substance, because it is already a type of matter which exists in its most basic, or purest form.

Another distinct characteristic of a pure substance is that, no matter how physically impossible it may be to isolate a pure substance, it can only be considered as pure if no impurities are detected. When it comes to their physical properties, such as their boiling or melting points, pure substances are non-changing, while mixtures are varying. For example, the boiling point of pure water is at 100 degrees Celsius, while the boiling point of alcohol mixed with water may be at a range of temperatures. To put it simply, pure substances are exactly what the name implies – pure, while mixtures are impure.

<span><span /></span>
4 0
3 years ago
A weather vane is a weather instrument used to measure wind
denpristay [2]

Answer:

Direction

Explanation:

A weather vane is a weather instrument that is used to measure the direction the wind is blowing in.

6 0
3 years ago
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