Answer:
Reacting hydrogen and oxygen gases to make water
Explanation:
Exothermic means that energy is released into the environment, so let's go through the process of elimination.
Allowing meat to thaw after taking it out of the freezer - NO it is endothermic, and takes energy/heat from the environment to thaw.
Popsicle melting on a warm summer day - NO also endothermic, the opposite of exothermic.
Boiling water in a beaker to convert it to steam - NO because we need to add heat, so it doesn't release any energy.
Rolling a ball up a hill - NO, for a ball to roll up a hill, it needs energy from something else, so it's not exothermic.
Reacting hydrogen and oxygen gases to make water - YES this reaction makes new bonds, which releases energy, so this is exothermic.
Among the following choices reacting hydrogen and oxygen gases to make water is an exothermic reaction as it releases energy as new bonds are formed.
What is an exothermic reaction?An exothermic reaction is defined as a chemical reaction which involves release of energy in the form of light,heat .In these reactions, energy is transferred from system to surroundings rather than taking energy from surroundings into system as in endothermic reactions.
In an exothermic reaction,change in enthalpy is negative.Therefore, it can be inferred that net amount of energy which is required to start the exothermic reaction is less than the net amount which is released by the reaction.
Examples of exothermic reactions are combustion reactions, detonation of nitroglycerin , neutralization reactions and nuclear fission.
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11. Samantha was asked to measure out 10 g of salt in a lab. She mistakenly measures out 15 g instead. Calculate
the percent error. Make sure your answer has the correct number of significant figures!
Answer:
50%
Explanation:
Expected measurement required = 10g
Actual measurement observed = 15g
The percentage error is given as proportion the difference between the actual and expected measurement or values and the expected value value expressed as a percentage.
[(Actual - Expected) / Expected] × 100%
[(15 - 10) / 10)] × 100%
(5 / 10) × 100%
0.5 × 100%
50%
Therefore, the percentage error in the measurement is 50%
formula for soda glass
Answer:
composition of soda-lime glass is 73% SiO2 – 15% Na2O − 7% CaO − 4% MgO − 1% Al2O3 [129,132,133].
The Soda glass formula is SiO2, Na2O, CaO, Al2O3, K2O, SO3, MgO, Fe2O3, TiO2
Soda glass is a chemical compound that stands out for being the most widely used material to make windows, bottles, glasses, among others.
This compound is characterized by being chemically stable, reasonably hard, and extremely versatile because it can be recycled since it can be melted to make new products.
Its chemical formula is made up of other compounds such as:
SiO2, is Silicon OxideNa2O, is sodium oxideCaO, is calcium oxideAl2O3, is aluminum oxideK2O, is potassium oxideSO3, is sulfur oxideMgO, is magnesium oxideFe2O3, is iron oxideTiO2, is Titanium OxideAdditionally, the compounds found in the highest proportion in glass are SiO2 (74 atoms) and Na2O (13 atoms).
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Chemistry is often called the __________ science because it involves the study of the materials in the universe and the changes these materials undergo
Answer:
Central
Explanation:
Chemistry is often called the central science because of connects the physical sciences, life sciences and applied sciences.
Chemistry is the study of matter and changes undergone by matter. This makes chemistry to occupy a central place in many scientific disciplines including medicine, engineering, pharmacy, geology etc. Basic knowledge of chemistry is usually required by experts in these disciplines.
Answer it answer it answer it
Answer:
[tex]\Large \boxed{\mathrm{A}}[/tex]
Explanation:
Rust formed from iron and oxygen combining is a chemical change, because in a chemical change, the resulting substance(s) will have different properties from the substance(s) before the chemical change.
I cant comment... So is it Right?
Does Na2 gas posses metallic character? Explain your answer..
Explanation:
It contains Na2 molecules and the atoms in this molecule are held together by a purely covalent bond because the electronegativity of the two atoms is identical.Metallic bonding would not kick in until you make clusters of quite a few atoms. Such clusters would likely not be very stable because thermodynamically the larger the clump of material the more stable it gets. So they tend to coalesce until you have chunk of metal.Metallic bonding is in a sense a form of covalent bonding, but it is very collective (delocalized over a great many atoms) and electron deficient (there are more states than electrons to fill them up with, leading to conductive properties. This means that “a metallic bond” is a bit of an oxymoron like a forest with only one tree.Reply me in commentsYes, Na2 gas possesses a metallic character.
Does NA contain metallic bonds?In the stable state, metal sodium functions as an array of Na+ ions which can be surrounded by way of a sea of 3s electrons. However, it would be wrong to consider metal sodium as an ion when you consider that the ocean of electrons is shared by using all of the sodium cations, quenching the nice fee.
Sodium most effective has one valence electron. So, in metallic bonding, it is able to only donate one electron to be delocalized at some point of the structure. In steel bonding, the real bonding is the electrostatic force between the effective cations and the delocalized electrons.
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If you have a little air in a balloon, find the volume of the balloon if the mass is 0.6 g and the density of the air is 0.0012 g / mL
Hey there!:
Mass = 0.6 g
Density = 0.0012 g/mL
Volume = ??
Therefore :
Density = mass / Volume
0.0012 = 0.6 / V
V = 0.6 / 0.012
V = 500 mL
Hope this helps!
How many gram of zinc will have to be treated with dilute hydrochloric acid to liberate 1.85 dm³ of hydrogen at 27°C and 750mmHg?
Answer:
Explanation:
given
volume=1.85 d m^3
T=27 degree C=27+273 k=300 k
P=750 mmHg
mass of zinc=?
we know that PV=nRT
n=m/M
PV=mRT/M
M for zinc=65.4
PVM=mRT
m=PVM/RT
m=750*1.85*65.4/0.0821*300
m=90742.5/24.63
m=3684
hope this will help u
What happens when two objects when they are brought closer together The mass of both objects decrease The mass of both objects increase The gravitational force between them decreases The gravitational force between them increases
Answer:
The correct option is
The gravitational force between them increases
Explanation:
According to Newton's law of universal gravitation states that the force of attraction between two bodies is directly proportional to the product of the masses of the bodies and inversely proportional to the square of the distance of their centers from each other.
The formula for universal gravitation is given as follows;
[tex]F_{1} = F_{2} =G \times \dfrac{m_{1} \times m_{2}}{r^{2}}[/tex]
Where;
F₁, and F₂ = The gravitational forces of attraction on each mass
G = The gravitational constant
m₁ = The mass of one body
m₂ = The mass of the body
r = The distance between the centers of the two bodies
Therefore, the gravitational force of attraction on each object is inversely proportional to the as the distance between the centers of the two bodies
When the distance between the centers of the two bodies decreases, the two objects are brought closer together, the gravitational force of attraction between them increases.
Answer:
Gravitational force between two objects of masses m1/m2
Explanation:
is defined by Gm1xm2/r^2, where G is a universal constant, and r is the distance between the masses. This shows you why B is wrong; it would increase. Also, A is not a good choice, as shown. In the case of B, it would increase by say, 2/1 to 4/1 by doubling ones mass. In C's case the bottom would decrease on the fraction alot (square) if they were moved closer, thus the force would be greater.
Explanation:
in other words the answer is The gravitational force between them increases
if 193 ml of chlorine gas was collected at 21 celsius, what volume would it have if the temperature dropped to 0 celsius
Answer:
New volume of chlorine gas (V2) = 179 ml (Approx)
Explanation:
Given:
Volume of chlorine gas (V1) = 193 ml
Temperature of chlorine gas (T1) = 21°C = 21 + 273 = 294 k
New temperature of chlorine gas (T2) = 0°C = 0 + 273 = 273 k
Find:
New volume of chlorine gas (V2) = ?
Computation:
Using charle's law
V1 / T1 = V2 / T2
193 / 294 = V2 / 273
V2 = 179.21
New volume of chlorine gas (V2) = 179 ml (Approx)
What are half reaction
Answer:
When you don't have a complete reaction.
Explanation:
Happens a lot between a solvent and a solute. The solute may not bind well with the solvent I.e. water.
What is the formula of the ion hydrogen sulfite, which has a charge of -1
There are two types of ions in chemistry, one is cation and the other is anion. Anion is the negative charge ion. Therefore, the formula of hydrogen sulfite ion is HSO₃⁻
What is chemical Compound?Chemical Compound is a combination of ions, ions forms by combination of element and element forms by combination of atoms in fixed proportion.
According to our question the chemical compound from which hydrogen sulfite ion is coming is sulfurous acid that is H₂SO₃. So to get hydrogen sulfite ion we need to remove one hydrogen ion that is H⁺ from the chemical compound sulfurous acid.
The balanced reaction is
H₂SO₃[tex]\rightarrow[/tex]H⁺ + HSO₃⁻
From above reaction we can see that the charge over hydrogen sulfite ion is -1
Therefore the formula of hydrogen sulfite is HSO3-
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A baseball has a mass of 135 grams and a softball has a mass of 270 grams. In which of the following situations would they have the same momentum? The baseball and softball are thrown at the same speed in the same direction.
Answer:
The baseball is thrown twice as fast as the softball in the same direction.
Explanation:
does the tendency to gain electrons decrease as we go down grp 17?
Explanation:
Hi, there!!!!
Let me simply clear you..
Yes,The tendency to gain electrons (in nonmetal) decreases when we go down group 17.
The reason for above answer is when we go downwards in periodic table then the atomic size increases with the addition of number of shells and force of attraction between the nucleus and valance shell decreases. The force of attraction between the nucleus and valance shell becomes weaker due to which the force of attracting the electrons gets decreased.
So, we can say that the tendency to gain electrons decreases as we go down in periodic table.
Hope it helps....
100 cm^3 of oxygen diffuses through a Porous in 3second how long will it take 150 cm^3 of sulphur (iv) oxide diffuse through the same pot? ( oxygen= 16 sulphur = 32)
Answer:
3.18 seconds
Explanation:
Given the following :
Volume of oxygen (V1) = 100cm^3
Time taken (t1) = 3 seconds
Volume of Sulphur (iv) oxide (v2) = 150cm^3
From Graham's Law of diffusion:
(r1/r2) = √(m1/m2)
Where r = rate of diffusion
m = molar mass
Note rate (r) = (volume / time)
[(V1/t1) ÷ (v2/t2)] = √(m1/m2)
(v1/t1) * (t2/v2) = √(m1/m2)
m1 = 02 = (16 * 2) = 32
m2 = SO2 = (32 + (16 * 2)) = 64
(100/3) * (t2/150) = √(32/64)
100t2 / 450 = √(32/64)
100t2 / 450 = √32 / 8
100t2 / 450 = √32 / 8
100t2 * 8 = 450 * √32
800t2 = 2545.5844
t2 = 2545.5844 / 800
t2 = 3.1819805
t2 = 3.18 seconds
It will take 3.18s for 150cm^3 of Sulphur (iv) oxide to diffuse through the same pot.
What does light travel in?
Answer:
Light travels as a wave.
Explanation:
But unlike sound waves or water waves, it does not need any matter or material to carry its energy along. This means that light can travel through a vacuum—a completely airless space. (Sound, on the other hand, must travel through a solid, a liquid, or a gas.)
When might Accurate length measurement be important?
Answer:
When you are going to measure small lengths or objects or when you are going to measure things with great accuracy.
Explanation:
What are the properties of alkynes
What is the independent variable of Smithers experience?
Please help controls and variables simpson? Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're supposed to staple a set of papers). Group A is given the special juice to drink while they work. Group B is not given the special...
Answer:
Smithers thinks that a special juice will increase the productivity of workers. He creates two groups of 50 workers each and assigns each group the same task (in this case, they're ... Group A is given the special juice to drink while they work. Group ... 1. Control Group. Group B. 2. Independent Variable. volume of special juice.
Explanation:
Answer:
1. Group B
2. The juice
3. The number of stacks of paper
4. the juice did not help improve a quicker process
5. Group A can be given the juice, Group B can be given the juice without the special ingredient
USE QUIZLET FLASH CARDS IT CAN HELP YOU WITH A LOT OF QUESTION
Which is the correct definition of metallic bonding? Select one: a. an array of positive ions in a sea of electrons b. complete transfer of valence electrons c. atoms share electrons to to be stable
Answer:
I believe it's A) an array of positive ions in a sea of electrons
If two solutions with concentrations of 0.4 M sugar and 0.7 M sugar respectively are separated by a semipermeable membrane, during osmosis there is a net flow of Group of answer choices sugar molecules from the dilute to the concentrated solution sugar molecules from the concentrated to the dilute solution water molecules from the concentrated to the dilute solution water molecules from the dilute to the concentrated solution
Answer: Water molecules from the dilute to the concentrated solution
Explanation:
During Osmosis if a solution is separerated by a semipermeable membrane, the solvent (typically water) from the less concentrated solution in terms of solute goes through the semipermeable membrane to the solution with the higher concentration so that the concentrations between the solutions can be balanced.
With the above solutions therefore, water molecules would move from the solution of 0.4M of sugar to the solution with a 0.7M of sugar through the semipermeable membrane.
During osmosis, water molecules move from the dilute to the concentrated solution.
OSMOSIS:
Osmosis is the movement of water molecules from a region of higher concentration (low concentration of solute) to a region of lower concentration (higher concentration of solute). The principle of movement is based on the concentration gradient i.e. difference in concentration across a semipermeable membrane. According to this question, two solutions have sugar concentrations of 0.4 M sugar and 0.7 M respectively and are separated by a semipermeable membrane. Therefore, water molecules will move from the dilute (0.4M) to the concentrated (0.7M) solution during osmosis.Learn more at: https://brainly.com/question/13655668?referrer=searchResults
The pH of a solution decreases by 2.0. How does the hydronium ion concentration of the solution change? Increases to 2 times the original concentration increases to 100 times the original concentration decreases to one one hundredth. Of the original concentration decreases to one half. Of the original concentration
Answer:
The hydronium ion concentration increases to 100 times the original concentration
Explanation:
The pH of a solution is defined as the negative logarithm of the hydrogen or hydronium ion concentration of that solution. It is given by the expression below:
pH = -log[H₃O⁺] = log[H₃O⁺]⁻¹
Assuming the solution was at neutral with original pH = 7;
The new pH of the solution will be = 7 - 2 = 5
At pH = 7;
log[H₃O⁺]⁻¹ = 7
[H₃O⁺]⁻¹ = 10⁷
[H₃O⁺] = 10⁻⁷
At pH = 5
log[H₃O⁺]⁻¹ = 5
[H₃O⁺]⁻¹ = 10⁵
[H₃O⁺] = 10⁻⁵
10⁻⁵ = 10⁻⁷ * 10²
But 10² = 100
Therefore, the hydronium ion concentration increases to 100 times the original concentration
Answer:
B
Explanation:
On Edge
Select the correct answer from each drop-down menu. At chemical equilibrium, the amount of because .
Answer:
The answer that completes the question are in BOLD:
At chemical equilibrium, the amount of PRODUCT AND REACTANT REMAIN CONSTANT because the RATES OF THE FORWARD AND REVERSE REACTIONS ARE EQUAL.
Explanation:
In a reversible chemical reaction, an equilibrium is said to be achieved when the rates of the forward reaction is equal to that of the reverse reaction. A reversible reaction is one in which products are formed from reactants simultaneously with the formation of reactants from products.
The combination of two or more substances called REACTANTS gives rise to another substance called PRODUCT, which can in turn give rise to Reactants again. With time, the rate at which the reactants give rise the products, which is called the FORWARD REACTION will be equal to the rate at which the products give rise to the reactants, which is called REVERSE REACTION. At this point, the chemical reaction is said to be in a STATE OF EQUILIBRIUM.
When the rate at which both reaction occurs becomes equal i.e. at an equilibrium state, the concentration of both the reactants and the products becomes constant i.e. no longer changes. Hence, the amount of the reactants forming the products is the same as the amount of products forming the reactants.
N.B: At chemical equilibrium, the amount of the reactants and products does not necessarily equals zero (0). It simply means that there is no net change in the concentration/amount of both reactants and products.
clearly distinguish between science and technology
Answer:
The words science and technology can and often are used interchangeably. But the goal of science is the pursuit of knowledge for its own sake while the goal of technology is to create products that solve problems and improve human life. Simply put, technology is the practical application of science.
Explanation:
Check the following images
Hope it helps!!!
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If the concentration of substance A of a reversible reaction in dynamic equilibrium increases, how will the equilibrium change?
A. It will shift to create more of substance A.
B. It will shift towards the reactants.
C. It will shift towards the products.
D. It will shift to create less of substance A.
Answer:
[tex]\boxed{It\ will\ shift\ to\ create\ less\ of\ substance\ A}[/tex]
Explanation:
If the concentration of any substance A in a dynamic equilibrium increases, The equilibrium will be shifted to its opposite side so that Substance A can be created less and the substance opposite to A can be created more so that a "dynamic equilibrium" can again be established.
how many significant figures are in 820 400.0 L
Answer:
7 significant numbers
How many moles are present in 136 grams of MgCl2? 1.46 mol 1.43 mol 2.27 mol
Answer:
1.43 mol
Explanation:
If each geometric shape represents a different type of atom, and atoms that are touching have chemically bonded with each other, which best describes this model? * 1. An element 2. A compound 3. A homogeneous mixture of two compounds 4. A heterogeneous mixture of two compounds 5. A homogeneous mixture of four elements 6. A heterogeneous mixture of four elements
Answer:
The correct option is;
3. A homogeneous mixture of two compounds
Explanation:
An homogeneous mixture is one where the components of the mixture are evenly dispersed such that the individual components cannot be seen to be isolated and distinguishable and having a constant composition of the constituents
The image displays three atoms (red circle, cyan triangle, and orange rectangle). The red circle appear to be bonded in pairs while the cyan triangles are bonded to the orange rectangles making a total of two compounds
The arrangement of the compounds in the mixture appear to be very evenly distributed to suggest an homogeneous mixture
The visibility of the compounds should be for an illustrative purpose.
Polymers formed from amino acids are called _____. proteins carbohydrates lipids nucleic acids
Answer:
Proteins
Explanation:
Amino acids act as monomers (a single unit used to form polymers) , the polymer will be a long chain of individual amino acids. An amino acid chain forms a protein. These proteins are also known as peptides.
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Tips for memorizing the first 20 elements of the periodic table?
Answer:
hydrant flying with balloon, balloon has lithp letting air out, bee: really yum balloon
= = = =
hydrogen helium lithium beryllium
be bore on the balloon, balloon pops, hydrant drops and makes a car bomb
= =
boron carbon
night row general gets hurt by car bomb nearby, that general gets off boat
=
nitrogen
wearing oxygen mask, mask is full of fluride gel, then he got neon teeth
= = =
oxygen fluorine neon
(try making a story out of the elements, use your imagenation)
I will give u tips to learn whole periodic table
1. Break down the table into sections
2. Spread out the memorisation process
3. Learn the elements in a song
4. Make none sense words made from element symbols
5. Use colour to learn element groups
6. Use mnemonic device to help remember the order of elements
I am sure this will be helpful for uuu
Explanation:
What is ionic bond and explain it
Answer:
An ionic bond is a chemical bonding involving the attraction between oppositely charged ions
Explanation:
On the periodic table, elements from group 1 and 7 are attracted to each other and when they bond, it's called ionic bonding. This is because of their valence electrons and ions.
Answer:
Ionic bonding is a type of chemical bonding that involves the electrostatic attraction between oppositely charged ions, and is the primary interaction occurring in ionic compounds. It is one of the main types of bonding along with covalent bonding.
