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.
which statement best describes a mole? it is 12 units of a given substance. it contains 6.02 1023 grams of sodium chloride. it is the mass of 12 carbon atoms. it contains 6.02 1023 particles of a given substance.
Answer:
The correct option is;
It contains 6.02 × 10²³ particles of a given substance
Explanation:
A mole of substance is the standard scientific unit of measurement for the quantity of the substance which is made up of a large number of small particles such as molecules, ions, atoms, electrons or other entities.
The General Conference on Weights and Measures defines the mole as the amount of a substance that contains 6.02214076 × 10²³ units of entities
The number 6.02214076 × 10²³, is also known as Avogadro's number.
The statement which correctly describes the mole is; it contains 6.02 × 10^23 particles of a given substance.
The mole refers to the amount of substance that contains the same number of elementary entities as 12 g of carbon - 12. According to Avogadro's law, the number of elementary entities in a substance is 6.02 × 10^23. These elementary entities could be atoms, ions, molecules etc.
Therefore, the statement which correctly describes the mole is; it contains 6.02 × 10^23 particles of a given substance.
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What evidence demonstrates that chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes?
Answer:
The evidence that demonstrated that the Chlorine in the stratosphere is believed to come primarily from CFCs ( Chlorofluorocarbons) rather than from natural sources such as volcanoes was due to the study conducted in which the amount of chlorine in the stratosphere over the past 20 years was measured and it was discovered that there was an increase over the years. This also corresponded with a rise in CFCs over the same period which shows that the chlorine in the stratosphere was from man made chemicals such as chlorofluorocarbons.
Chlorine in the stratosphere is primarily from man-made chemicals rather than from natural sources such as volcanoes is evident as follows;
Discussion;
Most of the chlorine in the stratosphere is there as a result of human activities, as the figure below illustrates.
Many compounds containing chlorine are released at the ground.
Volcanoes can emit large quantities of hydrogen chloride, but this gas is rapidly converted to hydrochloric acid, which dissolves in rain water, ice, and snow and does not reach the stratosphere.
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in the symbol 3p4
a. the 3 represents the principal energy level
b. the p represents the principal energy level
c. the 4 represents the principal energy level
d. all of the above
help!
Answer:
a. the 3 represents the principal energy level
Explanation:
3 is the principal energy level. The p is the sublevel. 4 is the possible occupying electron.
An atom has 36 protons, 36 electrons and a mass
number of 80. How many neutrons are in this atom?
Answer:
44 neutrons
Explanation:
To find the neutrons of an atom subtract the atomic number from the mass of the atom
in this case
80-36=44
tge number of neutrons that are in that atom is 48
How is heat transferred through convection?
A. Heat is transferred by energy waves moving through space.
B. Heat is transferred through contact between molecules
C. Heat is transferred by light being changed into kinetic energy.
D. Heat is transferred by the movement of a liquid or gas.
Heat is transferred through convection by the movement of a liquid or gas and is denoted as option D.
What is Convection?this is defined as the process of heat flow through a fluid which include a liquid or gas.
This process doesn't involve contact between the object unlike in conduction. A typical example is the heat flow which occurs in the atmosphere thereby making it the most appropriate choice.
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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.
What is 16.30 to the 100th gram
Answer:
1.65485688 × 10121 grams
Explanation:
Aside from those discrete items, anything like rice or flour can be measured out to make up 100 grams. For example, 1/2 cup (125 ml or about 4 and 1/2 fl. oz) of dry rice weighs very close to 100 grams.
Sodium hydroxide and water will react at room temperature. What does this indicate about its activation energy? A. The activation energy is very low. B. The activation energy is at exactly 600 kJ. C. The activation energy is very high. D. The reaction cannot reach activation energy.
Answer:
The answer would be C.
Explanation:
I took a test with the same question.
The activation energy is very high. Hence, option C is correct.
What is activation energy?Activation energy is the sufficient amount of energy necessary to initiate a chemical reaction.
When sodium hydroxide (NaOH) dissolves in water, it is distributed into positively-charged sodium ions and negatively - charged hydroxide ions.
These cations and anions move around in the water, free and independent of each other, though cations tend to be surrounded more closely by anions and vice versa.
Hence, when sodium hydroxide and water will react at room temperature, the activation energy is very high.
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Do you think it’s important that forensics is categorized as a science? Why or why not?
brainliest to whoever gets it the soonest, what SI unit do you use to measure the length of a book, and what tool and unit for the volume of a box?
Answer:
The SI unit of volume is the cubic meter (m 3 ), which is the volume occupied by a cube that measures 1 m on each side. This very large volume is not very convenient for typical use in a chemistry laboratory. A liter (L) is the volume of a cube that measures 10 cm (1 dm) on each side.
Which of the following is an example of a consumer? Tree Sun Rabbit Mushroom
Answer:
rabbit
Explanation:
Answer:
rabbit
Explanation:
the rabbit is the consumer because the sun "produces" the tree and mushroom, the rabbit comes along and eats the mushroom which was produced by the sun.
begging u to answer Which is not an inter molecular force? Select one: a. Inter atomic bonds b. van der waals forces c. hydrogen bonds
Answer:
a-Interatomic bonds
Explanation:
First of all, it is not a force. Let alone be molecular force.
Chromium is dissolved in sulfuric acid according to the following equation: Cr + H2SO4 ⇒ Cr2 (SO4) 3 + H2
a) How many grams of Cr2 (SO4) 3 can be obtained by reacting 165 g of 85.67% H2SO4 of purity?
b) If 485.9 g of Cr2 (SO4) 3 are obtained, what is the yield of the reaction?
Answer:
[tex]\large \boxed{\text{a)188.4 g; b) 98.67 $\, \%$}}[/tex]
Explanation:
We will need a balanced chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 98.08 392.18
2Cr + 3H₂SO₄ ⟶ Cr₂(SO₄)₃ + 3H₂
To solve the stoichiometry problem, you must
Use the molar mass of H₂SO₄ to convert the mass of H₂SO₄ to moles of H₂SO₄ Use the molar ratio to convert moles of H₂SO₄ to moles of Cr₂(SO₄)₃ Use the molar mass of Cr₂(SO₄)₃ to convert moles of Cr₂(SO₄)₃ to mass of Cr₂(SO₄)₃
a) Mass of Cr₂(SO₄)₃
(i) Mass of pure H₂SO₄
[tex]\text{Mass of pure} = \text{165 g impure} \times \dfrac{\text{85.67 g pure} }{\text{100 g impure}} = \text{141.36 g pure}[/tex]
(ii) Moles of H₂SO₄
[tex]\text{Moles of H$_{2}$SO}_{4} = \text{141.36 g H$_{2}$SO}_{4} \times \dfrac{\text{1 mol H$_{2}$SO}_{4}}{\text{98.08 g H$_{2}$SO}_{4}} = \text{1.441 mol H$_{2}$SO}_{4}[/tex]
(iii) Moles of Cr₂(SO₄)₃
The molar ratio is 1 mol Cr₂(SO₄)₃:3 mol H₂SO₄ [tex]\text{Moles of Cr$_{2}$(SO$_{4}$)}_{3} = \text{1.441 mol H$_{2}$SO}_{4} \times \dfrac{\text{1 mol Cr$_{2}$(SO$_{4}$)}_{3}}{\text{3 mol H$_{2}$SO}_{4}} = \text{0.4804 mol Cr$_{2}$(SO$_{4}$)}_{3}[/tex]
(iv) Mass of Cr₂(SO₄)₃ [tex]\text{Mass of Cr$_{2}$(SO$_{4}$)}_{3} = \text{0.4804 mol Cr$_{2}$(SO$_{4}$)}_{3} \times \dfrac{\text{392.18 g Cr$_{2}$(SO$_{4}$)}_{3}}{\text{1 mol Cr$_{2}$(SO$_{4}$)}_{3}} = \textbf{188.4 g Cr$_{2}$(SO$_{4}$)}_{3}\\\text{The mass of Cr$_{2}$(SO$_{4}$)$_{3}$ formed is $\large \boxed{\textbf{188.4 g}}$}[/tex]
b) Percentage yield
It is impossible to get a yield of 485.9 g. I will assume you meant 185.9 g.
[tex]\text{Percentage yield} = \dfrac{\text{Actual yield}}{\text{Theoretical yield}} \times 100 \, \% = \dfrac{\text{185.9 g}}{\text{188.4 g}} \times 100 \, \% = \mathbf{98.67 \, \%}\\\\\text{The percentage yield is $\large \boxed{\mathbf{98.67 \, \%}}$}[/tex]
Please help me... how do I draw this...
Draw diagrams to show the bonding in each of the following compounds:
a) calcium fluoride (CaF2)
Answer:
Hope it helps!!!
............
In the Lewis structure, the Ca atom donates its two valence electrons to two F atoms.
The bonding in calcium fluoride (CaF₂) involves the transfer of electrons from calcium (Ca) to fluorine (F), resulting in the formation of ionic bonds.
Each F atom gains one electron to achieve a stable electron configuration of eight electrons in its outermost energy level. The electrostatic attraction between the positively charged Ca ion (Ca²⁺) and the negatively charged F ions (F⁻) holds the compound together.
It's important to note that the diagram represents a simplified 2-dimensional representation of the compound's structure. In reality, the compound adopts a three-dimensional crystal lattice structure, with each Ca ion surrounded by eight F ions and each F ion surrounded by four Ca ions.
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Please help, this assignment is to hard for me. :(
Answer:
603000 J
Explanation:
The following data were obtained from the question:
Energy required (Q) =...?
Mass (M) = 10000 g
Specific heat capacity (C) = 2.01 J/g°C
Overheating temperature (T2) = 121°C
Working temperature (T1) = 91°C
Change in temperature (ΔT) =.?
Change in temperature (ΔT) =T2 – T1
Change in temperature (ΔT) = 121 – 91
Change in temperature (ΔT) = 30°C
Finally, we shall determine the energe required to overheat the car as follow:
Q = MCΔT
Q = 10000 × 2.01 × 30
Q = 603000 J
Therefore, 603000 J of energy is required to overheat the car.
Is this example of a direct proportion or an inverse proportion?
A. Direct proportion
B. inverse proportion
Answer:
Inverse proportion occurs when one value increases and the other decreases. For example, more workers on a job would reduce the time to complete the task. They are inversely proportional.
Answer:
A
Explanation:
3.0 cm x 4.0 cm x 1.0 cm
[?]cm^3
Explanation:
Hi there!!
you asked to multiply these all right,
you can simply multiply it ,
=3cm × 4 cm × 1cm
= 12cm^2×1cm (4×3=12)
= 12cm^3 (12×1=12)
Therefore, theanswer is 12 cm^3.
Hope it helps..
In a mass spectrometer, the ions are sorted out in which of the following ways?
A. By accelerating them through electric field
B. By accelerating them through magnetic field
C. By accelerating them through electric and magnetic field
D. By applying a high voltage
Answer:
C
Explanation:
The ions are first accelerated electrically, and then bended magnetically to sort them and record them.
A cylinder containing 14.71 L of helium gas at a pressure of 169.1 atm is to be used to fill toy balloons to a pressure of 1.086 atm. Each inflated balloon has a volume of 2.414 L. What is the maximum number of balloons that can be inflated? Report your answer to 1 decimal place. (Remember that 14.71 L of helium at 1.086 atm will remain in the exhausted (empty) cylinder)
Answer:
The number of balloons is 948.8.
Explanation:
The number of balloons can be calculated as follows:
[tex] N = \frac{V_{f}}{V_{T}} [/tex]
Where:
[tex]V_{f}[/tex]: is the volume at 1.086 atm
[tex]V_{T}[/tex]: is the balloon volume = 2.414 L
The volume at 1.086 atm can be found using Boyle's law:
[tex] P_{i}V_{i} = P_{f}V_{f} [/tex]
[tex] V_{f} = \frac{P_{i}V_{i}}{P_{f}} = \frac{169.1 atm*14.71 L}{1.086 atm} = 2290.5 L [/tex]
Now, the number of balloons is:
[tex] N = \frac{V_{f}}{V_{T}} = \frac{2290.5 L}{2.414 L} = 948.8 [/tex]
Therefore, the number of balloons is 948.8.
I hope it helps you!
Drag each characteristic to the correct category. Viruses do not possess all the characteristics of life. Identify those characteristics that viruses display and those they don't display.
Answer:
Virus is living due to reproduction and non-living due to crystal appearance.
Explanation:
Characteristics that viruses display is the ability of reproduction in which they increase in population which is a living character and have DNA or RNA which help them to make exact copies of itself. Virus is parasitic in nature because it causes harm to the living host such as humans, animals and plants. Some characteristics that viruses don't display are that they are not like living cells, have no membrane around them, no organelles such as mitochondria, golgi bodies, endoplasmic reticulum and lysosomes etc. Viruses are present in crystal form outside the cell.
A mixture of gasoline and air explodes when it encounters a spark. This is
known as
O A. a synthesis reaction
O O O
B. a precipitation reaction
C. fuel efficiency
o
D. a combustion reaction
SUBMI
Answer:
D. A combustion reaction
Explanation:
Suppose you were given a substance and asked
to determine whether or not it was a plasma. Write
the characteristics you would look for to identify
the substance.
Answer:Particles in plasmas collide more often.
Plasma particles have high kinetic energy (they move quickly).
Plasma particles are far apart.
The ionized particles have no fixed volume
Explanation:
Plasma is the fourth form of matter which has freely moving electrons in it. The substance can be identified as plasma if its particles collide often and are far apart.
What is plasma?Plasma is a type of matter other than solids, liquids, and gas. They have similar properties to that of gas. Plasma particle collides are often like gases as they move freely in space. Like gases that have no definite shape and volume.
The plasma particles have ionic charges, positive and negative resulting in high kinetic energy. This property allows them to show electromagnetism and electrical conductivity.
The ionized particles are due to the high temperature that allows them to have the property of electrical conductivity and compression.
Therefore, the particles of plasma are ionized and have high kinetic energy.
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When two ionic compounds are dissolved in water, a double replacement reaction can... Group of answer choices occur if two of the ions form an insoluble ionic compound, which precipitates out of solution occur if the ions react to form a gas, which bubbles out of the solution never occur since all ions are in water occur if the ions react to form a gas, which bubbles out of the solution ionic compounds only react with nonmetals
Answer:
occur if two of the ions form an insoluble ionic compound, which precipitates out of solution
Explanation:
When two ionic compounds are dissolved in water, a double replacement reaction takes place if two of the ions form an insoluble ionic compound, which precipitates out of solution. In double displacement reaction ions switch partners. And hence, produce an insoluble precipitate.
Which of these scientist is know for his work in understanding climate change a : edwin hubble b : christian doppler c : warren washington d : charles kuen kao
Answer: just trust me its c
Explanation: i dont cap
According to the table, a 23-30 watt CFL provides __________ lumens and is equivalent to a ________ incandescent bulb.
Answer:
The correct options are;
1. 1,600
2. 100 Watts
A 23-30 watt CFL provides 1,600 lumens and is equivalent to a 100 Watts incandescent bulb
Explanation:
Brightness is measured in lumens and watts measure energy usage therefore with the use of an energy saving light bulb, the same lumination can be obtained at a lower energy usage.
According to a comparison chart for LED Lights vs. Incandescent Light Bulbs vs. Compact Fluorescents (CFLs) from USAI lightening website 23-30 watts CFL has a light output of 1,600 and is therefore produces enough light as a 100 Watts Incandescent Light Bulb
Also according to energy.gov website, CFLs save up to 75% energy such that a 23-30 watt CFL can produce the same illumination as a 100 watt incandescent bulb
Therefore we have, a 23-30 watt CFL provides 1,600 lumens and is equivalent to a 100 Watts incandescent bulb.
Answer:
1600 lumens, 100 watt incandescent
Explanation:
100% on edge (:
Which Nobel gas electron structures do the atoms in a
molecule of hydrogen chloride attain?
And can you tell me why aswell please?
Answer:
The noble as structures attained are helium and argon
Explanation:
The electron configuration of chlorine atom is 1s²2s²2p⁶3s²3p⁵
The elecron configuation of hydrogen is 1s¹
The electron configuration of argon atom is 1s²2s²2p⁶3s²3p⁶
The elecron configuation of helium gas is 1s²
Therefore, in the hydrogen chloride molecule the hydrogen and the chlorine each share one electron from the other atom to attain the the stable noble gas structure of helium for hydrogen and argon for chlorine.
A student made the Lewis dot diagram of a compound as shown. Mg is written with two dots shown on its top. Cl is written on the right side of Mg. Cl has seven dots around it. An arrow is shown from one dot on Mg toward the vacant space around Cl. Another arrow is shown from the other dot on Mg toward the vacant space around Cl. On the top, the art title is written as Students Lewis Dot Model. What is the error in the Lewis dot diagram?
Answer:
The dots were not properly located and arrows are not used in Lewis structures
Explanation:
If we intend to write a Lewis structure for a compound, that lewis structure must consist of only dots. These dots actually show the valence electrons on the outermost shell of the molecule.
We do not involve arrows when writing dot electron structures for compounds. The valence electrons of magnesium ought not to be written together because they are not a lone pair, rather they are two unpaired electrons. The use of an arrow suggests a coordinate covalent bond which is not the case here.
The correct lewis structure for MgCl2 is shown in the image attached to this answer.
Answer: B is the answer took the test
Explanation: both electrons of Mg should be transferred to one O atom...
. Fire can be extinguished by: - a. Lowering temperature below ignition temperature b. Cutting the supply of oxygen c. Removing non-combustible substances from surroundings d. Both a & b
Answer:
B. Cutting the supplies of oxygen
What is 9.871 x 10^-3 in standard form? *
Answer:
0.009871
Explanation:
[tex] 9.871\times 10^{-3} = 0.009871[/tex]
Answer:
.009871
Explanation:
