Answer:
In a physical change, the substances involved retain their original properties. A new substance is not formed. A physical change can be reversed. Chemical changes happen on a molecular level when two or more substances chemically bond together.
Mending a broken bone is a chemical change as to heal the bone enzymes are released which are chemicals.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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The atomic mass of Cu is 63.5. Find its electrochemical equivalent
Answer:
The electrochemical equivalent of copper, Cu, is 3.29015544 × 10⁻⁷ g/C
Explanation:
The given parameters are;
The element for which the electrochemical equivalent is sought = Copper
The atomic mass of copper = 63.5
The electrochemical equivalent, 'Z', of an element or a substance is the mass, 'm', of the element or substance deposited by one coulomb of electricity, which is equivalent to a 1 ampere current flowing for a period of 1 second
Mathematically, we have;
m = Z·I·t = Z·Q
We have;
Cu²⁺ (aq) + 2·e⁻ → Cu
Therefore, one mole of Cu, is deposited by 2 moles of electrons
The charge carried one mole of electrons = 1 Faraday = 96500 C
∴ The charge carried two moles of electrons, Q = 2 × 96500 C = 193,000 C
Given that the mass of an atom of Cu = 63.5 a.m.u., the mass of one mole of Cu, m = 63.5 g
[tex]Z = \dfrac{m}{Q} = \dfrac{63.5 \ g}{193,000 \ C} = 3.29015544 \times 10^{-4} \, g \cdot C^{-1}[/tex]
∴ Z = 3.29015544 × 10⁻⁴ g/C = 3.29015544 × 10⁻⁷ g/C
The electrochemical equivalent of copper, Cu, is Z = 3.29015544 × 10⁻⁷ g/C
Which sample would show stronger (intermolecular) attractive forces, the cold water or the hot water?
Answer:
Cold water
Explanation:
A simple way to solve this kind of problems is to keep in mind that:
Solids have stronger intermolecular attractive forces than liquids, and liquids have stronger forces than gases.
Cold water behaves more similarly to solids than hot water. Conversely, hot water behaves more similarly to gases than cold water. Thus, cold water has stronger intermolecular attractive forces than hot water.
You write an invisible message on paper with lemon juice - when you heat the paper, the writing turns brown. Chemical or physical change
Answer: Chemical Change.
Explanation: Lemon juice has properties that, when heated, turn the paper brown. In the invisible ink science experiment, that is why it is used. In lemon juice, the acid prevents peeled fruit from browning, like apples and pears. The lemon juice has a bitter taste and is acidic.
Individual differences in a group is called what
A.adaptation
B.varation
C.natrual selection
D.selective breeding
True or False: There are five (5) of Newton's Laws of Motion *
Answer:
False
there is three
Explanation:
Three laws are combined together which is further known to us as Newton ’s three laws of motion. These three newton’s laws of motion are: Law I – Newton’s first law of motion Law II – Newton’s second law of motion
Hope this helps :)
What advantage does cross pollination have over self-pollination?
1. It allows a plant to have both male and female flowers.
2. It assures that there is genetic variety within each plant species.
3. It ensures that all offspring will be identical.
4. It allows a plant to fertilize itself.
Answer:
It allows all the plants to have one genetic
(Popcorn Stand) A salt shaker has 2.91 moles of NaCl, how many grams of NaCl are in the salt shaker?
Answer:
170 grams NaCl
Explanation:
Find the mass of NaCl by adding the two elements atomic mass
Na: 22.99
Cl: 35.45
22.99+35.45=58.44 g
Convert moles to grams.
2.91 mol NaCl * 58.44 g NaCl= 170.0604 g
A company uses chlorine to produce titanium chloride from titanium dioxide.
What is the relative formula mass (Mr) of titanium dioxide, TiO2?
Relative atomic masses (Ar): O = 16 Ti = 48 *
Answer:
80 g/mol
Explanation:
The Relative formular mass is the sum of the relative atomic masses of the elements present in the molecule.
TiO2;
There is one Ti atom and 2 O atom. Their atomic masses is given as;
TiO2 = 48 + 2(16) = 48 + 32 = 80 g/mol
Brainlist to who gets it right first
Which feature of the leaves is an adaptation for obtaining energy
A. Their short height
B. Their large size
C. Their pointed tips
D. Their unique shape
Answer:
B their larger size . this is right
Answer:
The answer is B. here is proof. Plz mark brainliest.
Explanation:
Hi, help with these two questions.
1. Write the isotope notation for an atom with 9 protons and an atomic mass of 20.
2. Write the isotope notation for an atom with 13 protons and 12 neutrons.
Answer:
Answered below
Explanation:
1) Atomic number is usually the number of protons
Since the atom is a neutral atom, Number of protons is equal to the number of electrons.
Thus means that we have 9 electrons and our atomic number is 9.
Atomic mass number is given as 20.
The is topic notation makes use of the atomic number and mass number.
Atomic number of 9 denotes fluorine.
Thus, the isotopic notation is written as attached;
2) we are told that an atom has 13 protons and 12 neutrons.
Similar to A above,
Atomic number is 13.
Now, number of neutrons + number of protons = mass number.
Thus;
Mass number = 13 + 12 = 25
Element with atomic number of 12 is magnesium
Thus,isotopic notation is as attached.
Help need fast !!!!!!
Answer:
Sodium oxide NA2O
2) N8CL
3) HO2
4) LISO3
Answer:
Sodium oxide NA2O
2) N8CL
3) HO2
4) LISO3
Explanation:
Given 4.20 x 1022 molecules of He gas, what mass of He do you have?
0.279 g He
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Atomic Structure
Reading a Periodic TableAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
4.20 × 10²² molecules He
Step 2: Identify Conversions
Avogadro's Number
[PT] Molar Mass of He - 4.00 g/mol
Step 3: Convert
Set up: [tex]\displaystyle 4.20 \cdot 10^{22} \ molecules \ He(\frac{1 \ mol \ He}{6.022 \cdot 10^{23} \ molecules \ He})(\frac{4.00 \ g \ He}{1 \ mol \ He})[/tex]Multiply/Divide: [tex]\displaystyle 0.278997 \ g \ He[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
0.278997 g He ≈ 0.279 g He
A student did an investigation to determine the effect the amount of air would have on plant growth. She planted identical
plants in 4 separate closed containers with different volumes of air. She measured the height of the plants after they had
grown for 3 weeks.
What is the dependent (responding) variable in her investigation?
Answer:
Explanation:
The responding variable always is measured against the variable that you have control over.
In this case, you have control over the volume of air.
The responding variable is the amount the plant has grown. This would be a good long term experiment to try for a science fair or just because you might be interested. It's a good simple idea.
If you find yourself rushing to complete many different tasks at once, it may be useful to
a Work at home to get each task done as soon as possible
b. Recruit another co-worker to do your normal tasks
C. Clarify the deadlines for each of the tasks with your boss
d. Stop working on the tasks until someone asks about them
Answer:
its c
Explanation:
because i have the most wrinkly brain
If you find yourself rushing to complete many different tasks at once, it may be useful to clarify the deadlines for each of the tasks with your boss.
What do you do when you have many tasks at once?It is common in an office setting to be assigned many tasks to be completed within a short time frame. However, all these tasks must be prioritized in order.
Hence, If you find yourself rushing to complete many different tasks at once, it may be useful to clarify the deadlines for each of the tasks with your boss.
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(blank) are the fastest form of radiation?
Answer: Gamma particles
Answer:
Gamma rays, are the fastest.
Explanation:
They literally move at the speed of light, I hope this helps you.
Name 5 things that the periodic table includes about 1 atom for each element:
1.
2.
3.
4.
5.
Answer:
They are listed below
Explanation:
The 5 things that the periodic table includes are;
1. Name of the element
2. The symbol of the element
3. Atomic number of the element
4. Relative atomic mass
5. Electron configuration
The nuclear equation below represents the alpha decay of 222/86 Rn --> 4/2 He + X
What is the mass number of the element represented by X?
Answer: The mass number of X is 218.
Explanation:
Alpha decay : When a larger nuclei decays into smaller nuclei by releasing alpha particle. In this process, the mass number and atomic number is reduced by 4 and 2 units respectively.
General representation of an element is given as: [tex]_Z^A\textrm{X}[/tex]
where,
Z represents Atomic number
A represents Mass number
X represents the symbol of an element
General representation of alpha decay :
[tex]_Z^A\textrm{X}\rightarrow _{Z-2}^{A-4}Y+_2^4\alpha[/tex]
[tex]_{86}^{222}\textrm{Rn}\rightarrow _{84}^{218}\textrm{Po}+_2^4\textrm{He}[/tex]
which pair contributed to the development of political parties in the United States ?
Answer: D
Explanation: I got it right
How many moles are in 88.0 g of carbon dioxide (CO2)?
PLEASE HELP MEEEEEE< ;-(
1.What is the amount of aluminum chloride produced from 40 moles of aluminum and 40 moles chlorine?
2.What is the amount of aluminum chloride produced from 80.0 grams of aluminum and 80.0 grams chlorine?
Answer:
= 0.4448 mol
Explanation:
id.k frfr
A 3.5L flexible container holds a gas at 250K. What will the new volume be if the temperature is increased to 400K?
Answer: 5.6L
Explanation:
Just did it on an assignment
A 3.5L flexible container holds a gas at 250K. The new volume will be 5.6 L, if the temperature is increased to 400K.
What is Charles Law ?Charles law is an ideal gas law which states that at a constant pressure volume of a gas is directly proportional to the absolute temperature.
It is expressed as
[tex]\frac{V_1}{T_1} = \frac{V_2}{T_2}[/tex]
where,
V₁ = initial volume
T₁ = initial temperature
V₂ = final temperature
T₂ = final temperature
Now put the values in above formula, we get
[tex]\frac{V_1}{T_1} = \frac{V_2}{T_2}[/tex]
[tex]\frac{3.5\ L}{250\ K} = \frac{V_2}{400\ K}[/tex]
[tex]V_{2} = \frac{3.5\ L \times 400\ K}{250\ K}[/tex]
[tex]V_{2} = \frac{1400}{250}[/tex]
V₂ = 5.6 L
Thus, from the above conclusion we can say that A 3.5L flexible container holds a gas at 250K. The new volume will be 5.6 L, if the temperature is increased to 400K.
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What are two functions of dermal tissue in plants?
A.Control the entry and exit of water
B.Cover the outside of plants
C.Contain cells that connect to form pipes
D.Transport water and food
Answer:
A and B
Explanation: Dermal tissue functions to protect the plant from injury and water loss.
a ___________________ is the phase when the moon is between the sun and the earth and cannot be seen.
like before, I put chemistry because there is no science subject.
Help!
If you were travelling at 45 miles per hour, how long would it take to travel a distance of 340 miles?
Pls help me with this question: This diagram represents the process of?
A.selective breeding
B.natural selection
C.metamorphosis
D.germination
Answer:
A
Explanation:
Selective Breeding
Is your answer because if you look closely to the pic you see the process
Hope this helps:)
Pls mark brainlist
Answer:
A
Explanation:
i don't understand this problem
?Mg+?02=?Mg0
Explanation:
2Mg + O2 ➖ 2MgO
hope it helps
what happens when u mix blood and water
Answer:
Blood and water
Explanation:
pleaseeeeeeeeeeeeeeeeeeeeeeee helppppppppppp
Approximately how many grams of KBr will dissolve in 100g of water at 50C?
60g
70g
80g
90g
Answer:
the answer would be to your problem here is 90g
Explanation:
This is an unbalanced equation representing a chemical reaction HgO->Hg+O2 (two is supposed to be small and on the bottom right part of the O) Which equation is the correctly balanced chemical equation for this reaction? A. HgO->Hg+20 (and a tiny 2 next to the 20) B. 2Hgo->Hg+0 (and a tiny 2 next to the 0) C. 2HgO->2Hg+0 (and a tiny 2 next to the 0) D. 2Hgo->Hg+20 (and a tiny 2 next to the 20)
Answer: C. [tex]2HgO\rightarrow 2Hg+O_2[/tex]
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The skeletal chemical equation will be:
[tex]HgO\rightarrow Hg+O_2[/tex]
The balanced chemical equation will be:
[tex]2HgO\rightarrow 2Hg+O_2[/tex]
The correctly balanced chemical equation for the reaction [tex]HgO - > Hg + O_{2}[/tex] is: C. [tex]2HgO - > 2Hg + O_{2}[/tex]
The law of conservation of mass states that mass can neither be created nor destroyed; it can only be transferred from one location to another. As a result, the mass of the products is required to be the same as the mass of the reactants.
On both the reactant and product sides of the reaction, the identical amount of atoms of each element is required. Therefore, the equations used in chemistry are balanced.
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as the train rushes down the hill the kinetic energy of the train _____ and the gravitational potential stored between the train and earth ________