Any molecule can be represented by a formula that lists all the atoms in that molecule. Each element is represented by its atomic symbol in the Periodic Table – e.g. H for hydrogen, Ca for calcium. If more than one atom of a particular element is present, then it’s indicated by a number in subscript after the atomic symbol — for example, H2O means there are 2 atoms of hydrogen and one of oxygen.
If there is more than one of whole groups of atoms, then that’s shown with a bracket around them. For example, calcium hydroxide has one calcium (Ca) for every two hydroxides (OH), so is written as Ca(OH)2.
If a charge is present, it’s indicated in superscript, with a sign (+/-) and a number if more than one charge is present. For example, calcium ions have two positive charges so are written Ca2+.
Sometimes a formula can be written in a way that gives an indication of the structure. A chemical equation shows a reaction taking place. On the left-hand side are the reactants, the molecules that take part in the reaction. On the right-hand side are the products, the molecules that are created in the reaction. Each side must contain the same number of each kind of atom. An arrow between them indicates the direction the reaction is expected to occur:
Ca + Cl2 → CaCl2
Calcium + chlorine → Calcium chloride
If there are two or more of any molecules, that’s indicated with a number in front of the molecule:
CH4 + 2O2 → CO2 + 2H2O
One methane molecule + two oxygen molecules → one carbon dioxide molecule and two water molecules
An equation may sometimes specify which phase each molecule is in – whether it’s solid, liquid, or gas, or if it’s dissolved. This is written in brackets after the molecule – (s) for solid, (l) for liquid, (g) for gas, and (aq) for ‘aqueous’, meaning dissolved in water. For example, solid calcium carbonate reacts with carbonic acid in water to form calcium bicarbonate, which is much more soluble so becomes dissolved in water:
CaCO3 (s) + H2CO3 (aq) → Ca(HCO3)2 (aq)
Solid calcium carbonate + dissolved carbonic acid → dissolved calcium bicarbonate
All chemical reactions can actually proceed in either direction. Most of the time, one direction is expected to take place more strongly, so the arrow is written in that direction. However, many common reactions happen in both directions simultaneously, creating an equilibrium where the reactions are taking place but there is no net change in concentration from one side to the other. This is indicated with the symbol ⇌.
For example, carbonic acid in water is continually breaking down into bicarbonate and hydrogen ions – but the ions are also continually joining back together.
H2CO3 ⇌ HCO3– + H+
Carbonic acid ⇌ bicarbonate + hydrogen ions
Pretend your friend was absent from class today...
Write what you would say if you had to explain how and why elements to
your friend.
Answer:
how and why elements what?? why they exist?? im gonna assume that's what you meant, so elements exist because we're all on earth and without elements, we don't have resources to live. the earth is made of elements and if there were none, we wouldn't even have a planet
Explanation:
^
36 g of KOH was dissolved in 800 mL of water. What is the
molality of the solution? (Molar mass of KOH = 56 g/mol,
density of water = 1.00 g/mL) ___ m.
Answer: 0.8 m
Explanation:
1) Draw a particle picture of liquid lemonade turning into a solid popsicle
BEFORE
AFTER
Explanation:
The particles are further apart in liquids than in solids so when the lemonade changes from a liquid to a solid, the particles would become closer.
A solution is any mixture of two or more substances.
TRUE or
FALSE
Answer:
true
Explanation:
Which best describes nuclear fusion? O A nucleus spontaneously splits and absorbs energy O Two nuclei spontaneously combine and absorb energy. O A nucleus collides with a neutron and splits, releasing energy. O Nuclei combine to form a heavier nucleus, releasing energy.
Answer: Nuclei combine to form a heavier nucleus, releasing energy.
Explanation: e.g two deuterium nucleus (Hydrogen-2 isotopes) forms an He nucleus and energy is released.
Nuclear fusion is when nuclei combine to form heavier nuclei, releasing energy.
What is Nuclear Fusion?Nuclear fusion is a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei and subatomic particles (neutrons or protons). The difference in mass between the reactants and products is manifested as either the release or absorption of energy.
The release of energy with the fusion of light elements is due to the interplay of two opposing forces: the nuclear force, a manifestation of the strong interaction, which holds protons and neutrons tightly together in the atomic nucleus; and the Coulomb force, which causes positively charged protons in the nucleus to repel each other.
Nuclear fusion is also observed in stars.
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A rarefraction is generated when particles move
A:together
B.closer
C.under
D.apart
At a high concentration do you have more or less particles per unit volume
Answer:
More particles per unit volume
Explanation:
Concentration means the amount of solute in a solution. Now, the amount of solute also means the number of particles of solute present in a solution.
Hence, when we use the term "high concentration", we imply that the amount of solute present or the number of particles present in a solution is high.
Thus, at high concentration, there are more solute particles than solvent particles in a solution.
WILL GIVE BRAINLIEST!!
What adaptation helps the pelican to swim?
Big wings
Long beak
Strong legs
Webbed feet
Help for brainliest
Answer:
those things that looks like cristals
PLEASE HELP.
What does the atomic number of an element tell us?
A) the number of neutrons in an atom of an element
B) the number of protons in an atom of an element
C) the number of protons, electrons, and neutrons in an element
What is not matter in chemistry??
Explanation:
Examples of things that are not matter include thoughts, feelings, light, and energy. Light, heat, kinetic and potential energy, and sound are non-matter because they are massless.
Which of these elements will successfully create a 1:1 bond with Carbon (C)
Carbon (C)
Silicon (Si)
Beryllium (Be)
Oxygen (0)
Answer:
Option B, Silicon
Explanation:
The valency of Carbon is 4 as it has four electrons in its outermost shell
The valency of Si is also four hence C
Hence Silicon can form 1:1 bond with the carbon
Valency of Beryllium is 2, hence it can not form 1:1 bond with carbon. Similarly the valency of oxygen and carbon are way different to form 1:1 bond
hence, only option B is correct
In the buffer solution CH3COsH(aq) -> H3O+(aq) + CH3CO2-(aq)
A. H3O+ is an acid, and CH3CO2H is its conjugate base.
B. CH3CO2H is an acid, and CH3CO2- is its conjugate base.
C. H3O+ is an acid, and CH3CO2- is its conjugate base.
D. CH3CO2H is a base, and H3O+ is its conjugate acid
In the buffer solution CH₃COOH (aq) ---> H₃O⁺(aq) + CH₃CO₂⁻(aq):
CH₃CO₂H is a base, and H₃O⁺ is its conjugate acid.
Option D is correct.
What is an acid?An acid is described as a molecule or ion capable of either donating a proton, known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid.
From the buffer solution above, H₃O⁺ is the conjugate acid because it donates a proton (H⁺) to a base CH₃CO₂H.
In conclusion, A conjugate acid, within the Brønsted–Lowry acid–base theory, is described as a chemical compound formed when an acid donates a proton (H⁺) to a base.
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Convert 444 cal to joules
Answer: 1
Decimal Answer: 1.858
In order to tell the difference between microwaves and visible light in the blue range, which of the following measurements should be made?
Answer:
microwaves should be made
Answer:
answer choices plzzzzz
ima edit my answer wht are the choices
Explanation:
mrk mE BRAINLIEST PLZZZZZZZZZZZz
Consider the statement:
“The following report presents the results of our laboratory tests, which support the conclusion that our new treatment for acne is safe and effective with minimal possible side effects.”
What questions should a person ask themselves to determine if this scientific study is reliable?
What does the acne medicine look like?
What does the acne medicine smell like?
Were laboratory tests conducted by the same company that produces the acne medicine?
Were laboratory tests conducted in a laboratory with more than 100 employees?
The question the person should ask him/herself to probably check for authenticity of the drugs is "Were laboratory tests conducted by the same company that produces the ac[tex]\cap[/tex]e medicine?". Option C. This is further explained below.
What is a scientific study?Generally, scientific study is simply defined as a method that includes making conjectures and deriving answers as logical implications from the hypotheses.
In conclusion, Were laboratory tests conducted by the same company that produces the ac[tex]\cap[/tex]e medicine should be questioned as medical companies should look to other labs for authenticity confirmation.
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How many joules of heat are needed to raise the temperature of 30.0 g of aluminum from 22°C to 80°C, if the specific heat of aluminum is 0.90 J/g°C?
Answer: There are 1566 joules of heat needed to raise the temperature of 30.0 g of aluminum from 22°C to 80°C, if the specific heat of aluminum is 0.90 J/g°C.
Explanation:
Given: Mass = 30.0 g
Specific heat = [tex]0.90 J/g^{o}C[/tex]
[tex]T_{1} = 22^{o}C[/tex]
[tex]T_{2} = 80^{o}C[/tex]
Formula used to calculate the heat energy requires is as follows.
[tex]q = m \times C \times (T_{2} - T_{1})[/tex]
where,
q = heat energy
m = mass of substance
C = specific heat capacity of substance
[tex]T_{1}[/tex] = initial temperature
[tex]T_{2}[/tex] = final temperature
Substitute the values into above formula as follows.
[tex]q = m \times C \times (T_{2} - T_{1})\\= 30.0 g \times 0.90 J/g^{o}C \times (80 - 22)^{o}C\\= 1566 J[/tex]
Thus, we can conclude that there are 1566 joules of heat needed to raise the temperature of 30.0 g of aluminum from 22°C to 80°C, if the specific heat of aluminum is 0.90 J/g°C.
A rocket launches because of __________.
A. an opposite reaction
B. it's large mass
C. its gravity
D. air resistance
Answer:
an opposite reaction
Earth's gravity is still pulling down on the rocket. When a rocket burns propellants and pushes out exhaust, that creates an upward force called thrust. To launch, the rocket needs enough propellants so that the thrust pushing the rocket up is greater than the force of gravity pulling the rocket down.
13) Which "conversion tool" below would you use to complete this
conversion?
In 2Fe+3Cl2=2FeCl3, how much iron (Fe) is needed to produce 4 moles of FeCl3?
In 2Fe+3Cl2=2FeCl3, how much FeCl3 is produced when 5 moles of Fe react in excess chlorine?
Answer:
4 mol Fe
5 mol FeCl₃
Explanation:
Step 1: Write the balanced equation
2 Fe + 3 Cl₂ ⇒ 2 FeCl₃
Step 2: Calculate how much iron (Fe) is needed to produce 4 moles of FeCl₃
According to the balanced equation, the molar ratio of Fe to FeCl₃ is 2:2.
4 mol FeCl₃ × 2 mol Fe/2 mol FeCl₃ = 4 mol Fe
Step 3: Calculate how much FeCl₃ is produced when 5 moles of Fe react in excess chlorine
According to the balanced equation, the molar ratio of Fe to FeCl₃ is 2:2.
5 mol Fe × 2 mol FeCl₃/2 mol Fe = 5 mol FeCl₃
A certain element has a half-life of three years.
If you currently have a 10g sample of that element and you know that it has undergone five half-life decays, how many grams of the element were in the sample originally?
A
150g
B
160g
C
320g
D
50g
(C) 320 g
Explanation:
A = A02^(-t/hl)
where hl = half-life
A0 = original amount
A = present amount
t = elapsed time = 5 half-lives
10g = A02^(-5) = A0/32
A0 = 32×(10 g) = 320 g
The speed you read from your speedometer is your ____________________. *
average speed
direction
instantaneous speed
distance
Answer:
it is your instantaneous speed
Explanation:
PLESE HELP WILL GIVE BRAINLYESTY
Imagine that you are Sir Isaac Newton. Write a short autobiographical statement that talks about who you are, where you’re from, and some of your important contributions.
Answer:
My name is Isaac Newton and I am a scientist. I am known as one of the most important scientists in history. I was born in Woolsthorpe, England on January 4, 1643. My father, a farmer who was also named Isaac Newton, had died three months before my birth. My mother remarried when I was three years old and left me in the care of my grandparents.
Explanation:
why do different people have differently shaped proteins?
The sequence of amino acids in the chain determines how the chain will fold up to make the protein, so different proteins have different three-dimensional shapes. ... This is because proteins form attachments and interact with many other molecules and structures inside organisms.
Use the dichotomous key to identify these plant leaves.
Leaves from which plant are shown?
pine
catalpa
dogwood
maple
Answer:
catalpa
Explanation:
i took the test
NEED HELP ASAP 20 POINTS !!!!!What does a subscript in a chemical formula tell you? For example the 3 in Rb3PO4 the number of atoms of the element symbol it follows the number of atoms of the element symbol it is in front of the number of molecules
Answer:
The answer should be A
Explanation:
because the definition of a subscript is that they indicate the number of atoms of an element present in am molecule or formula unit.
Answer:
The first choice. The rule is go left. Those subscript numbers always talk about the element to the left of them.
Explanation:
The straight forward answer is the first one.
You should always answer that when reading the chemical make up of molecules. Let's look at some examples.
C8 H18
Consider the 8. It must be describing how many carbons there are. If it was meant for the hydrogen, then what does the 18 mean? You wouldn't know.
Now look at something a lot more complicated.
Mg3(PO4)2
Use the going left rule. That satisfies Mg doesn't it? There are 3 of them and 3 is correct.
The two at the end is also straightforward if you think about it. It must be telling you how many molecules are in the brackets. If that were not so, then you wouldn't be able to tell what it did. So there are 2 PO4
But you still have the 4 to deal with. Use the going left rule again. 4 must be telling you how many oxygens you have inside the brackets. There are 4 of them.
If you have 2.9 x 10^21 atoms of nitrogen, how many moles do you have?
Answer: Approximately [tex]0.48 \times 10^{-2} \ \text{ mole}[/tex]
============================================================
Explanation:
There are roughly 6.02 * 10^23 atoms in one mole of any element. So we have 6.02 * 10^23 atoms in one mole of nitrogen.
We can then do the following conversion:
[tex]\left(2.9 \times 10^{21} \ \text{ atoms of nitrogen} \right)\times \left(\frac{1 \ \text{ mole}}{6.02 \times 10^{23} \ \text{ atoms}}\right)\\\\\frac{2.9 \times 10^{21}}{6.02 \times 10^{23}} \ \text{ mole}\\\\\frac{2.9}{6.02} \times 10^{21-23} \ \text{ mole}\\\\0.48172757 \times 10^{-2} \ \text{ mole}\\\\0.48 \times 10^{-2} \ \text{ mole}\\\\[/tex]
What is the pH of a 0.21 M solution of LiOH?
Answer:
13.32
Explanation:
pOH=-log(0.21)=0.68
pH=14-pOH=14-0.68=13.32
How many molecules are in 5.00 grams of NH3?
a 0.294
b 0.333
C 1.77 x 1023
d 6.68 x 1022
e 2.00 x 1023
Answer:
C. 1.77x 1023
Explanation:
Not sure please correct me if im wrong
What is described by the frequency of a wave?
A. The speed the wave is traveling through space
B. The number of waves that pass a point in 1 second
C. The height of the wave from trough to peak
D. The distance from one peak to the next peak
Taking into account the definition of frecuency, the statement "The number of waves that pass a point in 1 second" describes the frequency of a wave.
Definition of frequencyFrequency is the number of vibrations that occur in a unit of time. Its unit is s⁻¹ or hertz (Hz).
In other words, the frequency in wave phenomena, such as sound, electromagnetic waves (such as radio or light), electrical signals or other waves, expresses the number of times the phenomenon is repeated per unit of time. For example, if a wave repeats ten times per second, it means that it has a frequency of ten cycles per second.
SummaryFinally, the statement "The number of waves that pass a point in 1 second" describes the frequency of a wave.
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