Answer:
Total gram of Ca = 99.26 g
Explanation:
Given:
Mass of CaCl₂ = 277.45 g
Find:
Mass of Ca
Computation:
Ca = 40 g/mol
Cl₂ = 2 (35.5) g/mol = 71 g/mol
Total CaCl₂ = 111 g/mol
Total gram of Ca = [40 / 111] 277.45 g
Total gram of Ca = 99.26 g
1. Mg + HCl … + ….
2. NaOH + HNO3 … + ….
3. KOH + CuCl2 … + ….
4. Na2SO4 + BaCl2 … + ….
5. HCl + FeO à … + …
Explanation:
The answer is mentioned above.
Hope it helps.
list one difference between blended fibres and regenerating synthetic fibres
Answer:
blended is better than synthetic fibre. because blended fabrics have quality of synthetic and natural fibres so they are more better than fabrics. For example terrycot. Blended Fibres are considered better than individual synthetic fibres because they show the advantages of 2 or more fibres.
3. Prepare a saturated solution of common salt in hot water. Suspend a thick cotton wick into this solution. Keep it undisturbed for a few days. You will find that common salt crystals will deposit on the wick. Is the change physical or chemical?
Answer:
physical
Explanation:
The change is physical.
A physical change involves a reversible change to the physical properties of substances, whereas a chemical change involves an irreversible change to the chemical properties of substances through a chemical reaction.
The dissolution of common salt is a physical change because the common salt can be retrieved by evaporating off the water. This is what was manifested by the deposition of common salt crystals on the wick.
what are the 2 main methods of combination of elements??
Answer:
to make them react to each other to form a compound
Explanation:
mark me as brainliest pls
Answer:
An element is a material that consists of a single type of atom. Each atom type contains the same number of protons. Chemical bonds link elements together to form more complex molecules called compounds. A compound consists of two or more types of elements held together by covalent or ionic bonds.
What characteristic best describes the low entropy associated with solids?
O A. The atoms are held together with strong bonds.
O B. The atoms are arranged in a rigid structure.
C. The solid has a high specific heat capacity
D. The atoms in a solid are mostly metals.
Answer:
B. The atoms are arranged in a rigid structure.
Explanation:
Because the entropy of solids depends on the structure of the atoms, a rigid structure has less randomness = less entropy. So, the answer is B.
Answer:
b
Explanation:
a p e x :)
Làm thế nào để tắt mỗi chất ra khỏi hỗn hợp gồm bột nhôm bột sắt và bột gỗ?
Answer:
Dùng nam chân hút đc bột sắt ra khỏi hỗn hợp
Bột gỗ và bột nhôm thì bột gỗ tan trong nước còn bột nhôm thì không
Explanation:
Nice !Pesticides and fertilizers are a major cause of
O air pollution
O acid rain
o the greenhouse effect
O groundwater pollution
Answer:
it means air pollution Environment. The chemicals and nutrients found in fertilizers, while beneficial for agricultural crops, can be lethal in high doses for fish, birds and other wildlife. Pesticides, designed to kill pests chemically, are also dangerous when leached into soil or groundwater supplies.
Answer: Freezing point depression
Explanation:
freezing point depression is a phenomenon that describes why adding a solute or solvent results in the lowering of the freezing point of the solvent
Define physical and chemical properties, provide three examples of each, discuss their reversibility, and explain the fundamental differences between them.
Answer:
Physical properties are defined as the properties which can be observed without changing its chemical composition.
For example: color, volume, and molecular weight.
Chemical properties are defined as the properties which can be observed only after changing chemical identity of the substance.
For example: reactivity, toxicity, and flammability.
The fundamental differences between physical and chemical properties are as follows:
Chemical properties are related to chemical bonds of the substance while physical properties are not.
In chemical properties, chemical identity of substance changes while physical properties do not have any change.
Chemical properties predict the reaction of substance while physical properties only describe the appearance of the substance.
Explanation:
Answer:
A measurable property that can be observed typically and explains any matter or organism's appearance and physical behavior is called a physical property. Examples of physical properties are appearance, boiling point, freezing point, melting point, colors, odor, mass, density, solubility. Properties that are only observed during a reaction or change in the composition of a matter is called a chemical property. These properties describe the internal part of anything and explain how it behaves when reacted with other chemical substances. Examples are enthalpy, entropy, reactivity, flammability, oxidation state, acidity, basicity. Some physical properties are reversible or sometimes irreversible. Like the change of states of matter is reversible, and the growth of an organism is irreversible. The same thing with the chemical properties. There are reversible chemical reactions(formation of ammonium chloride) and irreversible chemical reactions. (burning of a chemical substance). After knowing all about these properties, the most fundamental difference is that the physical properties can be measured without any chemical change in them. But a chemical property is measurable when the substance goes through a chemical reaction.
Explanation:
which statement is true about this reaction 14/7n + 1/1h ------> 15/8o
A. it is a practical source of energy on earth
B.it occurs only outside the solar system
C.its product is heavier than each of its reactants
D.it shows the critical mass of an element
Answer: answer is C
Explanation:
Its product is heavier than each of its reactants is true about this ₇N¹⁴ + ₁H¹ → ₈O¹⁵ reaction
What is Nuclear reaction ?A nuclear reaction is a reaction in which one or more than one nuclides are generate and it collides between two atomic nuclei or one atomic nucleus.
The reaction is
₇N¹⁴ + ₁H¹ → ₈O¹⁵
Now equating the mass number of both sides
14 + 1 = 15 + a
a = 0
Equating atomic number of both sides
7 + 1 = 8 + x
x = 0
Thus, we can say that its product is heavier than each of its reactants is true about this reaction
Hence, option C is correct answer.
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what charge does an atom that has gained electrons have?
Answer:
I think it's positive charge
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Chlorine and oxygen are both gases at room temperature. What are some characteristic properties of chlorine that distinguish it from oxygen?
Answer:
Well one characteristic is electical energy transforms into thermal energy and gases and the state of matter(one of the distinct form i which matter exist)
What mass of Fe(OH)3 is produced when 35 mL of 0.250 M Fe(NO3)3 solution is mixed with 55 mL of a 0.180 M
KOH solution? (this is a limiting reactant problem).
Answer:
0.35 g.
Explanation:
We'll begin by calculating the number of mole of Fe(NO3)3 in 35 mL of 0.250 M Fe(NO3)3 solution.
This is illustrated below:
Molarity of Fe(NO3)3 = 0.250 M
Volume = 35 mL = 35/1000 = 0.035 L
Mole of Fe(NO3)3 =?
Molarity = mole /Volume
0.250 = mole of Fe(NO3)3 / 0.035
Cross multiply
Mole of Fe(NO3)3 = 0.25 x 0.035
Mole of Fe(NO3)3 = 8.75×10¯³ mole
Next, we shall determine the number of mole of KOH in 55 mL of 0.180 M
KOH solution. This is illustrated below:
Molarity of KOH = 0.180 M
Volume = 55 mL = 55/1000 = 0.055 L
Mole of KOH =.?
Molarity = mole /Volume
0.180 = mole of KOH /0.055
Cross multiply
Mole of KOH = 0.180 x 0.055
Mole of KOH = 9.9×10¯³ mole.
Next, we shall write the balanced equation for the reaction. This is given below:
3KOH + Fe(NO3)3 —> Fe(OH)3 + 3KNO3
From the balanced equation above,
3 moles of KOH reacted with 1 mole of Fe(NO3)3 to produce 1 mole of Fe(OH)3.
Next, we shall determine the limiting reactant. This can be obtained as follow:
From the balanced equation above,
3 moles of KOH reacted with 1 mole of Fe(NO3)3.
Therefore, 9.9×10¯³ mole of KOH will react with = (9.9×10¯³ x 1)/3 = 3.3×10¯³ mole of Fe(NO3)3.
From the above illustration, we can see that only 3.3×10¯³ mole out of 8.75×10¯³ mole of Fe(NO3)3 given is needed to react completely with 9.9×10¯³ mole of KOH.
Therefore, KOH is the limiting reactant and Fe(NO3)3 is the excess reactant.
Next, we shall determine the number of mole of Fe(OH)3 produced from the reaction.
In this case, we shall use the limiting reactant because it will give the maximum yield of Fe(OH)3 as all of it is consumed in the reaction.
The limiting reactant is KOH and the mole of Fe(OH)3 produce can be obtained as follow:
From the balanced equation above,
3 moles of KOH reacted to produce 1 mole of Fe(OH)3.
Therefore, 9.9×10¯³ mole of KOH will react to produce = (9.9×10¯³ x 1)/3 = 3.3×10¯³ mole of Fe(OH)3.
Finally, we shall convert 3.3×10¯³ mole of Fe(OH)3 to grams. This can be obtained as follow:
Molar mass of Fe(OH)3 = 56 + 3(16 + 1) = 56 + 3(17) = 107 g/mol
Mole of Fe(OH)3 = 3.3×10¯³ mole
Mass of Fe(OH)3 =?
Mole = mass /Molar mass
3.3×10¯³ = Mass of Fe(OH)3 / 107
Cross multiply
Mass of Fe(OH)3 = 3.3×10¯³ x 107
Mass of Fe(OH)3 = 0.3531 ≈ 0.35 g.
Therefore, 0.35 g of Fe(OH)3 was produced from the reaction.
A new stable element with an atomic number of 120 and an atomic mass of 246 is created in a particle accelerator. Enough of this element is created to determine that it combines with chlorine in a 1:2 ratio. Element 120 should be placed in the same group as _____ on the periodic table.
Answer:
Be,Mg,Ra etc
Explanation:
It should be palced in group 2A because as it reacts with chlorine in ratio of 1:2 . It's valancy is 2 and is metal as it react with non metal donating two electrons .
one more thing it fits there orderly
Did you know that before pencil erasers were added on in 1858. people got rid of pencil markings
with white breadcrumbs? Which would erase pencil markings better, an eraser or white bread
crumbs?
Make a hyphotesis plz
Answer:
I guess eraser is better than bread crumbs
Erasers would be better than white bread or crumbs to erase the pencil marks because they would not leave any food marks on the paper and using bread crumbs.
What is an eraser?An eraser is an object of stationary which is used to remove pencil marks from the paper. It is used during writing, when we write something wrong, we could erase or remove the writing from the paper. It is very useful for small children because they usually make mistakes while studying.
Erasers are made from the milk of rubber plants. The milk is collected from the plants, and then it is mixed with chemicals and set down, and then cut into pieces.
Thus, Erasers would be preferable to utilizing bread crumbs or white bread because they would not leave any food stains on the paper after erasing the pencil markings.
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A chemical engineer is developing a process for producing a new chemical. One step in the process involves allowing a solution of potassium hydroxide to react with a solid. Which action would most likely increase the reaction rate for this step? using larger pieces of the solid using a more concentrated potassium hydroxide solution adding water to the system
Answer:
using a more concentrated potassium hydroxide
Explanation:
The option that would likely increase the rate of reaction would be to use a more concentrated potassium hydroxide.
The concentration of reactants is one of the factors that affect the rate of reaction. The more the concentration of the reactants, the faster the rate of reaction.
Granted that there are enough of the other reactants, increasing the concentration of one of the reactants will lead to an increased rate of reaction.
Hence, using a more concentrated potassium hydroxide which happens to be one of the reactants would likely increase the rate of reaction.
Answer:
using a more concentrated potassium hydroxide
Explanation:
The identity of an element is determined by
A. the number of neutrons
B. the weight of the nucleus
C. the number of protons
D. the number of electrons
The answer is Number of Protons !
Answer: D. the number of protons
Explanation: The number of protons shows you what the Atomic number of an element is on the Periodic table of elements.
The identity of an element is primarily determined by the number of protons it possesses. The Option C.
What determines the identity of an element?Each element on the periodic table has a unique number of protons in its nucleus which is referred to as its atomic number. This fundamental property of an element distinguishes it from other elements and determines its place on the periodic table.
While number of neutrons and electrons can vary within an element, it is the number of protons that defines its identity. Thus, the correct answer is C: the number of protons.
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number of moles from the formula is multiplied by the atomic mass of each _______, and then all those masses are added together.
A)
atom
B)
particle
C)
molecule
D)
electron
Answer:
D. electron
Explanation:
An atom X has a proton number of 19 and relative atomic mass of 39.
(i) How many electrons, protons and neutrons are there in an atom of X?
(ii) How many electrons will there be in the outer energy level (shell) of an atom of X?
(iii) What is the electronic configuration of X?
Answer:
1) electron=19 Proton=19 Neutron=39-19=20
2) 1
3) in pic
Answer:
(i)electrons = 19; Protons = 19 Neutrons =39-19=20
(ii) 1
(iii) 2,8,8,1
Hope this helps.
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In human cells, a dynamic equilibrium exists between carbonic acid (H2CO3) and carbon dioxide (CO).
H2CO3(aq) = CO2() + H200
When a person exercises, the body's cells metabolize glucose to gain energy. This metabolism also causes an increase in the
concentration of carbon dioxide.
Le Chatelier's principle states that stresses applied to a system in dynamic equilibrium will cause the system to change in order to
alleviate those stresses. According to this principle, how would an increase in carbon dioxide concentration affect the system?
A. There would be a decrease in the concentration of carbonic acid.
В. There would be an increase in the concentration of glucose.
C. There would be an increase in the concentration of water.
There would be an increase in the concentration of carbonic acid.
D There would be an increase in the concentration of carbonic acid.
There would be an increase in the concentration of carbonic acid - this is how an increase in carbon dioxide concentration influences the system.
What is dynamic equilibrium?In chemistry, a dynamic equilibrium lives once a reversible reaction occurs. Substances transition between the reactants and products at equal rates, indicating there is no net change. Reactants and products exist formed at such a rate that the concentration of neither changes. It is a precise example of a system in a steady state. After a time, a reversible reaction in a closed system can get what we call a dynamic equilibrium.
The correct answer is option D.
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why does a desert cooler better on a hot dry day
Answer:On a hot dry day humidity will be less.when humidity decreases rate of evaporation increases
Answer:
The water that evaporates from a desert cooler takes in energy from the environment for filling up for the loss of energy during EVAPORATION making the environment cold.
Therefore, on a hot dry day, the Evaporation is more which means the environment will be colder.
Explanation:
I hope it is okay.
I learnt it last year, so I went back to my book and explained it better in my own way.
Thanks.
why solids do not undergo diffusion
Answer:
Solids do not undergo diffusion because it has a fixed structure (vibrates in a fixed position) and it also cannot be compressed.
Hoped this helped in any way
Have a nice day
D. Answer these questions.
1. What is chemistry?
2. What is scientific method?
Answer:
1.Chemistry is the scientific discipline involved with elements and compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a reaction with other substances.
2.The scientific method is an empirical method of acquiring knowledge that has characterized the development of science since at least the 17th century. It involves careful observation, applying rigorous skepticism about what is observed, given that cognitive assumptions can distort how one interprets the observations.
What is the pH of a 2.50×10^-4 M solution of sodium hydroxide
Answer:
Answer is 10.398(approx.)
Explanation:
NaOH ⇄ Na⁺ + OH⁻
pOH = -log[OH⁻]= -log(2.5×10⁻⁴) = 3.602
∴pH = 14 - pOH = 10.3989(approx.)
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Question 19 of 30
How does the distance over which the strong nuclear force acts compare to
the distance over which the other fundamental forces act?
O A. The distance is the same as the weak nuclear force and less than
gravitational and electrostatic forces.
B. The distance is the same as the weak nuclear, gravitational, and
electrostatic forces.
O c. The distance is larger than the weak nuclear force but less than
gravitational and electrostatic forces.
D. The distance is smaller than the gravitational force but later than
weak nuclear and electrostatic forces.
which of the following molecules would you expect to be optically active
1. CCl2F2
2. 2-methyl butane
3. butan-2-ol
Answer:
waaaaaaaaaaqwwwwwwwwwwww
How many moles are present in 136 grams of MgCl2? 1.46 mol 1.43 mol 2.27 mol
Answer:
1.43 mol
Explanation:
When a substance's particles are packed together tightly and have a definite shape and
volume...it is said to be in what state?
solid
gas
plasma
liquid
Answer:
solid
Explanation:
Define freezing....... Correct and detailed answers will be marked as Brainliest.
The transformation of liquid into solid when it reaches when it's temperature is below freezing point.
Answer:
Freezing:
When liquid is converted to solid, the process is called freezing.
Conditions for freezing:
1) Temperature must be lowered.
2) The temperature should be below 0 degree centigrade.
Example:
The conversion of "liquid water" into "ice".
=> We can use a "freezer" to freeze things.
Write the valence shell electronic configuration of an element present in the 3rd
period and Group IIIA,
Al= [Ar] 3s^2 3p^1
for the third period the principal quantum number is n=3. the third