Consider the following reaction:
Mg + 2H2O Mg(OH)2 + H2 ΔH = -353 kJ
This reaction is
A.
exothermic because heat is released.
B.
endothermic because heat is released.
C.
endothermic because heat is absorbed.
D.
exothermic because heat is absorbed.
Answer:
A
Explanation:
I think it's the answer
Millikan determined the electron's ______ .
Answer
In 1909, Robert Millikan and Harvey Fletcher conducted the oil drop experiment to determine the charge of an electron. ... Using the known electric field and the values of gravity and mass, Millikan and Fletcher determined the charge on oil droplets in mechanical equilibrium.
Millikan and fletcher determined the charge on oil droplets in mechanical equilibrium
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a magnesium ion has 12 protons and a charge of 2 . how many electrons does it contain?
Answer:
It contains 12 electrons.
when a tennis ball is dropped from a high distance is it elastic or inelastic collision? explain?
Answer:
An elastic collision.
Explanation:
When a ball is dropped to the ground, one of four things may happen: It may rebound with exactly the same speed as the speed at which it hit the ground. This is an elastic collision.
How many moles of water is 5.02x1018 molecules
of water?
Answer:8.334×10^-6 moles
Explanation:
a mole is 6.023×10^23
5.02×10^18 ÷ 6.023×10^23=8.33×10^-6
Use the chemical equation to complete the activity.
4Fe + 3O2 → 2Fe2O3
Iron (Fe) reacts with oxygen (O2) to form iron oxide. A scientist adds 15.4 grams of Fe to 3.6 grams of O2 to start the reaction. All of the iron and oxygen react to form iron oxide. Explain in detail how you can determine how many grams of iron oxide will be produced.
Use the law of conservation of matter in the explanation.
Answer:
14.54 g Fe2O3
Explanation:
The first step would be to balance the equation but since it's already balanced we don't have to worry about that.
Through the balanced equation, you can find the stoichiometry of the reaction, that is:
4 moles of Fe, react with 3 moles of O2, to produce 2 moles of Fe2O3
Chemistry (accurately stoichiometry) is all about ratios and proportions. The balanced equations gives you the standard ratio by which moles are produced.
So the next step (shown in the paper), is to convert the grams that are giving you in Moles, and you do this by dividing the number of grams given by the molar mass of the substance. The molar mass is the number of grams by which you can find exactly 6.022x10²³ molecules (one mole) of one specific substance.
15.4 g of Fe= 0.28 mol Fe
3.6 g of O2= 0.11 mol O2
Now that you have the quantity of moles, what you need to do is to look for the limitant reactant.
In a balanced equation, the number of moles in the reactants are the rules and they're gonna react completely with each other. If you want x quatity of reactants to react completely, then you will have to respect the proportion to the ratio given in the balanced equation.
But you will rarely follow the proportion so there will usually be a reactant that's gonna be limiting the reaction and one that is in excess. And how do you find this? Well, the easiest way to do it is:
Dividing the number of moles obtained by x element the coefficients of that element in the balanced equation. The one that has the smallest ratio, is the limitant reactants.Since the limitant reactant is gonna be limiting the reaction, all the stoichiometric procedures should be calculated through it, and in this case, the limitant reactant is O2.
But then how to establish the stoichiometric rule to find the number of Iron oxide (III) that's being produced?
Look back to the stoichiometry of the reaction:
To produce 2 moles of Fe2O3, you need 3 moles of O2.
But you have 0.11 mol O2.
Then establish a factor of conversion (shown in the picture)
The result is 0.07 mol of Fe2O3, but you need the answer in grams so you find the molar mass of Fe2O3 and then multiply it by the number of moles (0.07)
The answer is 14.54 g of Fe2O3
CHEMISTRY IS ALL ABOUT PROPORTIONS :D
Some acids like acetic acid and tartaric acid cannot be tasted
TRUE OR FALSE
The statement is a false.
An acid is a substance which when dissolved in water, produces hydroxonium ion, as the only positive ion.
Some properties of acid include:
They have sour tastes andStrong acids are corrosive.There are two types of acids which includes:
Strong acids: These are the acids that ionizes completely in solution.Weak acid: These are the acids that ionizes incompletely in solution.Examples of weak acid is acetic acid and tartaric acid.
They can be used as food substances like vinegar and naturally occurs on fruit like banana or grape.
Therefore, weak acids such as acetic acid and tartaric acid can be tasted.
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The given statement is False.
Some acids like acetic acid and tartaric acid can be tasted.
Organic acids, such as acetic, citric, malic, and fumaric acids in fruits and vegetables, and tartaric acid in wine, contribute significantly to the sour flavor of foods and beverages. Many inorganic acids taste sour in dilute solutions.
Tartaric acid is fairly water soluble and has a pronounced tart flavor. Tartaric acid is present naturally in grapes and bananas and has been shown to improve the flavor of grape and lime-flavored beverages. Tartaric acid may aid in the treatment of glucose intolerance and digestion.
Acetic acid is a colorless liquid having a sour flavor. Although it is most frequently associated with vinegar, this acid has a wide range of different applications in a variety of industries. Acetic acid is a colorless liquid that is composed of chemical compounds.
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what species has an atom with an oxidation number of 3
Would an alkaline earth metal make a good replacement for tin in a tin can?
Answer:
Definitely not. This is because the alkaline earth metal [basically group 2 elements] are reactive and will react with the contents of the can, contaminating it.
No, alkaline earth metals would not be a good replacement for tin in a tin can because alkali from alkaline earth metals react with tin and release hydrogen.
What are alkaline earth metals?Alkaline earth metals are present in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
They are called alkaline earth metals because their hydroxide and oxides are highly alkaline. Their metal oxides are found in the earth's crust.
These metals have 2 electrons in their outer shell, and they are highly reactive, so they will react with the tin in a tin can.
Thus, alkali from alkaline earth metals react with tin and generate hydrogen, hence they would not make an acceptable replacement for tin in a tin can.
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which best explains why water dissolves most salts?
Answer:
where are the answers?
Explanation:
Look at the graph. Which part of the line shows a time
when the object was not moving?
Help please I don’t know what to do
Calculate the molar mass for CO
Answer:28.01 grams
Explanation:
Methane has the chemical formula of CH4 and would, therefore, it would be
considered...
Answer:
compound
Explanation:
A compound contains more than one element.
Methane's chemical formula (CH4) indicates that it consists of one carbon atom and four hydrogen atoms.
Therefore, methane is a compound.
Find the molar mass of iron (III) nitrate, Fe(NO3)3
Answer:
Hey there are you doing are you doing I will tell you the answer
is change in color a physical change
Answer: A change in color is not always a chemical change. If one were to change the color of a substance in a non-chemical reaction scenario, such as painting a car, the change is physical and not chemical.
Solid → Liquid: Melting
Solid → Gas: Sublimation
Liquid → Gas: Vaporization
Gas → Liquid: Condensation
Explanation:
how many grams are in 4.5 x 10^22 molecules of water
Answer:
1.35 g
Explanation:
water is h2o, so the molar mass is 1.01x2+16.00=18.02. divide 4.5 x 10^22 by 6.022 x 10^23 to get 7.5 x 10^-2 (2 sig figs). 18.02 x 7.5 x 10^-2 is 1.35 g
calculate the number of atoms in a sample containing 3.5 g of silicon atoms
Answer:
there are 7. 505 x 1022 atoms in 3.5 grams of silicon.
Explanation:
So, 1 mole of silicon will have a mass of 28.0855 g and the number of atoms will be 6.022 x 1023. Therefore, there are 7. 505 x 1022 atoms in 3.5 grams of silicon.
Answer:
1 mole of silicon will have a mass of 28.0855 g and the number of atoms will be 6.022*1023 . Therefore , there are 7.505*1022 atom in 3.5 g of silicon .
giving brainliest, more chemistry questions being uploaded
Answer:
We have the atoms, and we have the molar mass of Vanadium (listed in the periodic table) which should be 50.94g/mol.
The first step is to convert the 4.18 x 10^23 atoms into moles by dividing the atoms by Avogadro's number (6.02 x 10^23)
(4.18 x 10^23)/(6.02 x 10^23) = 0.694 moles
Now we know that moles is equal to the mass divided by the molar mass. So now that we have the moles and the molar mass of Vanadium, we can rearrange the equation to find mass. Once you have rearranged it, you have to multiply the moles by the molar mass.
So 0.694 moles x 50.94g/mol = 35.35g of V
2NaOH(aq) + Cl2(g) -> NaCl(aq) + NaClO(aq) + H20(l)
Answer:
Cl2(g) + 2 NaOH(aq) = NaCl(aq) + NaClO(aq) + H2O(l)
Explanation:
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Use the key above to interpret the following incomplete chemical reaction.
Select the statements at apply in order to complete the model. (Choose 3)
A) The number of atoms in the products must be equal to the reactants.
B) One diatomic oxygen should be removed from the reactant side.
C) One unbonded carbon atom should be added to the product side of the equation
D) One carbon atom and two oxygen atoms are needed to balance the equation.
E) One carbon dioxide molecule should be added to the product side of the equation.
Answer:
Carbon dioxide molecule
Answer:a , d ,e
Explanation:
jusy took quiz
explain a mixture of molecules
Answer:
A mixture of molecules is a group of molecules in which there are multiple different elements and atoms, that are in either fixed proportions or random. There are heterogeneous and homogenous mixtures.
Explanation:
PLS HELP
Answer this question and I will mark you the braninliest! <3
Answer:
the left one
Explanation:
heavier means it goes faster
Calculate the following examples.
1. Ramji conducted an experiment in the field related to the rate of percolation. He observed that it took 30 minutes for 600 ml of water to percolate through the soil. Calculate the rate of percolation per hour.
2. Jigna takes 50g of dry powdered soil in a filter paper and slowly adds water to the soil from a 100 ml fully filled measuring cylinder. When water starts dripping from the filter paper, 60 ml of water is left in the measuring cylinder. Find out the percentage of water absorbed by the soil.
Answer:
12ml per hour and
69% LOL
1) The rate of percolation would be 0.33 ml/s
Percolation rate = volume of water/time
= 600/1800s
= 0.33 ml/s
2) The percentage of water absorbed would be 40%
Percentage of water absorbed = amount absorbed/total water x 100
amount of water absorbed = 100 - 60
= 40 ml
total amount of water = 100 ml
Percentage of water absorbed = 40/100 x 100
= 40%
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Given the equation
N2(g) +3H2 (g)--> 2NH3 (g)
1 mole of N2 gas is needed to completely react with 3 moles of H2 gas.
How many molecules of H2 gas are needed?
Answer:
1.81 x [tex]10^{24}[/tex] molecules H2
Explanation:
Use Avogadro's number:
3 moles H2 x 6.022 x [tex]10^{23}[/tex] molecules= 1.81 x [tex]10^{24}[/tex] molecules H2
Which of the following elements are most likely to form an ionic bond
K and Ca
S and Cl
K and Cl
C and O
Answer:
K (Potassium) and Cl (Chlorine)
Explanation:
Ionic bonds are formed with metals and nonmetals
Covalent bonds are formed only with nonmetals
Calcium and potassium are both metals
Sulfur and Chlorine are both nonmetals so they don't form ionic bonds
Carbon and Oxygen are both nonmetals so they don't form ionic bonds
Two gas jars are connected to each other, but they are separated by a closed valve. One gas jar contains oxygen, and the other contains hydrogen. What will happen when the valve is opened?
Answer Choices:
A. Oxygen and hydrogen molecules will mix because of random movement of their molecules.
B. Oxygen and hydrogen molecules will remain in separate jars because of different partial pressures.
C. Oxygen and hydrogen molecules will remain in separate jars because of different rates of expansion.
D. Oxygen and hydrogen molecules will mix because the molecules have a much lower volume than the volume of the jars.
When the valve is opened, oxygen and hydrogen molecules will mix because of random movement of their molecules.
What is diffusion?
Diffusion involves the movement of gas molecules from one region where they are in higher concentration to another region where they are in lower concentration.
When the valve is opened, oxygen and hydrogen molecules will mix because of random movement of their molecules.
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Answer:
Oxygen and hydrogen molecules will mix because of random movement of their molecules.
Explanation:
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The half-life of a radioactive isotope is 2.4 minutes. If you started with 100.0 grams, how many grams would be left after 7.2 minutes has elapsed? Explain how you arrived at your answer.
Answer:
12.5grams would remain after time has elapsed
Which statement describes how a substance melts?(1 point) Molecules in the substance gain kinetic energy and then become less tightly bound to each other. Molecules in the substance gain kinetic energy and then become less tightly bound to each other. Molecules in the substance lose kinetic energy and then become more tightly bound to each other. Molecules in the substance lose kinetic energy and then become more tightly bound to each other. Molecules in the substance lose kinetic energy and then become less tightly bound to each other. Molecules in the substance lose kinetic energy and then become less tightly bound to each other. Molecules in the substance gain kinetic energy and then become more tightly bound to each other. Molecules in the substance gain kinetic energy and then become more tightly bound to each other.
Answer:
Molecules in the substance gain kinetic energy and then become less tightly bound to each other.
Explanation:
According to the forces of attraction , for a substance to melt molecules in the substance gain kinetic energy and then become less tightly bound to each other.
What are forces of attraction?Forces of attraction is a force by which atoms in a molecule combine. it is basically an attractive force in nature. It can act between an ion and an atom as well.It varies for different states of matter that is solids, liquids and gases.
The forces of attraction are maximum in solids as the molecules present in solid are tightly held while it is minimum in gases as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.
The physical properties such as melting point, boiling point, density are all dependent on forces of attraction which exists in the substances.
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