Answer:
VSEPR theory
Explanation:
The valence shell electron pair repulsion theory was propounded by Gillespie and Nylom (1957).
The entire idea of the VSEPR theory is that the shape of a molecule depends on the electrostatic repulsion between electron pairs surrounding the central atom in a molecule which causes these pairs to be separated as far as possible.
The shapes of many molecules can be accurately predicted based on this model.
Which of the following should NOT be used to hold chemicals while they are being heated?
Question 5 options:
test tube
weigh boat
beaker
crucible
Answer: Weigh boat
Explanation:
they are disposable and will likely melt
Weigh boat among the following should not be used to hold chemicals while they are being heated ,therefore option (b) is correct.
What do you mean by weigh boats ?Weigh boats are ideal for general-purpose weighing, evaporating, dispensing, and storing applications. Compatible with balances and dryers, these pans support precise measurements.
A weigh boat is an open container often used in chemistry and bio chemistry. It is used if you want to weigh a sample very accurately.
A weigh boat is an object that is used to protect your balance from any object you want to weigh.
Weigh boat among the following should not be used to hold chemicals while they are being heated ,hence option (b) is correct.
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Chất tinh khiết là:
A. Có tính chất thay đổi
B. Có lẫn thêm vài chất khác
C. Gồm những phân tử đồng dạng
D. Không lẫn tạp chất
Answer:
The FitnessGram™ Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it continues. The 20 meter pacer test will begin in 30 seconds. Line up at the start. The running speed starts slowly, but gets faster each minute after you hear this signal. [beep] A single lap should be completed each time you hear this sound. [ding] Remember to run in a straight line, and run as long as possible. The second time you fail to complete a lap before the sound, your test is over.
fd
Define symbol and compound with an exomple.
what are two consents in this experiment
The number of cricket chirps
The temperature of each container
The kind of containers used
The number of crickets in each container
Answer:
the number of crickets in each container
Explanation:
to participate in the experiment you will have to know the crickets in the container
Magicians often use ‘flash powder’ in their acts. Flash powder contains 69.0% potassium chlorate (31.9% K, 28.9% Cl, 39.2% O) and the remainder is aluminium. Calculate the percentage composition by mass of each element in flash powder
Answer:
[tex]\rm K[/tex]: approximately [tex]22.0\%[/tex].
[tex]\rm Cl[/tex]: approximately [tex]19.9\%[/tex].
[tex]\rm O[/tex]: approximately [tex]27.0\%[/tex].
[tex]\rm Al[/tex]: [tex]31.0\%[/tex].
Explanation:
Consider a [tex]100\; \rm g[/tex] sample. There would be [tex]69.0\% \times 100\; \rm g = 69.0\; \rm g[/tex] of [tex]\rm KClO_{3}[/tex] and [tex]100.0\; \rm g - 69.0\; \rm g = 31.0\; \rm g[/tex] of [tex]\rm Al[/tex].
Out of that [tex]69.0\; \rm g[/tex] of [tex]\rm KClO_{3}[/tex]:
[tex]31.9\%[/tex] (by mass) would be [tex]\rm K[/tex]: [tex]31.9\% \times 69.0\; \rm g \approx 22.0\; \rm g[/tex].
[tex]28.9\%[/tex] (by mass) would be [tex]\rm Cl[/tex]: [tex]28.9\% \times 69.0\; \rm g \approx 19.9\; \rm g[/tex].
[tex]39.2\%[/tex] (by mass) would be [tex]\rm O[/tex]: [tex]39.2\% \times 69.0\; \rm g \approx 27.0\; \rm g[/tex].
Overall, the composition (by mass) of each element in this mixture would be:
[tex]\rm K[/tex]:
[tex]\begin{aligned} & \frac{31.9\% \times 69.0\; \rm g}{100\; \rm g} \\ =\; & 31.9\% \times 69.0\% \\ \approx \; & 22.0\%\end{aligned}[/tex].
[tex]\rm Cl[/tex]:
[tex]\begin{aligned} & \frac{28.9\% \times 69.0\; \rm g}{100\; \rm g} \\ =\; & 28.9\% \times 69.0\% \\ \approx \; & 19.9\%\end{aligned}[/tex].
[tex]\rm O[/tex]:
[tex]\begin{aligned} & \frac{39.2\% \times 69.0\; \rm g}{100\; \rm g} \\ =\; & 39.2\% \times 69.0\% \\ \approx \; & 27.0\%\end{aligned}[/tex].
[tex]\rm Al[/tex]:
[tex]\begin{aligned}& \frac{100\; \rm g - 69.0\; \rm g}{100\; \rm g} \\ =\; & 100\% - 69.0\% \\ =\; & 31.0\%\end{aligned}[/tex].
Match each step of the scientific method with its matching example.
Match Term Definition
A) The growth of green algae is recorded every day for several weeks and compared
B) The data recorded in the experiment supports the hypothesis about how algae reproduce.
C) Based on what other scientists have done, algae life cycles are affected by light.
D) Under the same temperature and water conditions, green algae is grown under natural light, blue light, and green light.
Experiment
Conclusion
Research
Analysis
Answer: I did the quiz and got it correct
Explanation:
Biosphere- B
Ecosystem- C
Biome- D
Habitat- A
Scientific Method
What is Scientific Method
A method or procedure that consists of systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.
Experiment- The growth of green algae is recorded every day for several weeks and compared
Conclusion- Under the same temperature and water conditions, green algae is grown under natural light, blue light, and green light.
Research-Based on what other scientists have done, algae life cycles are affected by light.
Analysis- The data recorded in the experiment supports the hypothesis about how algae reproduce.
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Am I correct?
(Plz don’t used this for points or typing random things…plz don’t)
Answer and Explanation:
The answers would be:
A. Domestic cats live in about 34% of homes in the United States. (Statistical statements are, most of the time, facts and not an opinion)
C. Modern domestic cats are closely related to Near Eastern wildcats. (Fact)
D. Cats eat rodents that can spread disease. (Fact)
The above statements are facts because they don't make a judgement or show a position on the topic, only show what is known and proven to be true.
B and E are incorrect because they take a side of the topic, in which someone else might disagree with the opinion. These opinions aren't proven to be true.
#teamtrees #PAW (Plant And Water)
I hope this helps!
need help asap!!!!!!!!!
Answer:
c. 2 and 3 only
Explanation:
When you compact the bag of trash you make it smaller, so the volume changes. And the density is the mass divided by the volume, so as the volume changed the density obligatorily change too
why is the Dna molecule able to open up and close?
Answer:
The breaking of the hydrogen bonds due to the force relieves the torsional stress stored in a double helix. As a result, the nucleotide strands rotate more freely about the axis of a helix and start unwinding. ... The DNA unzipping and the DNA unwinding result in a structural transformation from dsDNA to ssDNA.
How many Sodium (NA) Atoms are in Methylene?
Answer:
No Sodium(Na) in methylene
Explanation:
Methylene is an organic compound
Jane wants to study how a person's heart and lungs respond to intense
exercise. She measures the heart rate and breathing rate of 10 people before,
during, and after a 5K race. Which body systems is she studying?
A. Cardiovascular and respiratory
B. Skeletal and urinary
C. Digestive and nervous
D. Muscular and reproductive
SUBMIT
Identify the correct mole ratio for each substance.
Sodium chloride (NaCl)
Na:Cl = 1: _
Ammonium nitrate(NH.NO3)
H:0 = 4: _
Answer:
The mole ratio of H : O in ammonium nitrate is 4 : 3.
Explanation:
We are given a compound named ammonium nitrate having formula
There are 3 elements in this compound which are nitrogen, hydrogen and oxygen.
To calculate the mole ratio, we write the ratio of their subscripts. For this compound,
7.95x10 converted to the number is
7.95 × 10
= 79.5
This is the answer
How many joules of energy are required to melt 125 g of water?
Answer for this question is 45,000
Energy is referred to by scientists as the capacity for work. People have figured out how to transform energy from one form to another and then use it to accomplish tasks, making modern civilization possible.
Explain about the energy?Energy is the ability to do tasks. It can exist in various forms, including potential, kinetic, thermal, electrical, chemical, and nuclear.
Energy can take on a variety of shapes. Examples of these include: electrical energy, sound energy, chemical energy, nuclear or atomic energy, light energy, heat energy, mechanical energy, gravitational energy, and so on. Each form has the ability to shift or transform into the others.
The sun is one of the most significant energy sources. Most of the energy on earth comes from the sun, which is where it all began. We get
Answer for this question is 45,000
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In an exothermic reaction, heat is
released into the surroundings. How does this affect entropy?
particles in the surroundings move slower and have decreased entropy.
• B. The particles in the surroundings move faster and have increased entropy.
•C. The particles in the surroundings move
surroundings move slower and have increased entropy.
• D. The entropy is not affected by this.
Answer:
B. the particles in the surroundings move faster and have increased entropy
Explanation:
An exothermic process releases heat, causing the temperatures of the surroundings to increase. Entropy increases as temperature increases. Since an exothermic reaction releases heat to the surroundings, molecules in the surroundings will begin to move faster because they will absorb more energy, which increases their kinetic energy. An increase in temperatures means that the particles of the surroundings have greater kinetic energy. The faster moving particals have more disorder than particles that are moving more slowly at a lower temperature. Entropy is interpreted as the degree of disorder/randomness.
if any 1 studying 11th can u plz send me the chemistry notes for chapter 2 STRUCTURE OF AN ATOM lesson
plz send me honestly cause i have exam day after tommorow .so plz send unwanted answer
I BEG U
Answer:
What
You cant just send notes you also have to say where you are and which book you are using because others are different
Bài 19 với ạ, ai giúp em với ❤️❤️❤️❤️❤️
Answer:
we're are u from
Explanation:
also the writing from that paper look really cool
How many moles are there in 2.3 x 1024 atoms of
sulfur?
Explanation:
The steps given in the question are incorrect.
Step 1 should be convert atoms to moles (n). Step 2 should be convert moles (n) to mass (m).
Step 1
Use dimensional analysis to convert the number of atoms to moles.
1 mole atoms = 6.022 × 10²³ atoms
n(Ag) = 2.3 × 10²⁴ Ag atoms × (1 mol Ag/6.022 × 10²³ Ag atoms) = 3.8193 mol Ag
Step 2
Convert the moles of Ag to mass.
mass (m) = moles (n) × molar mass (M)
n(Ag) = 3.8193 mol Ag
M(Ag) = atomic weight on the periodic table in g/mol = 107.868 g Ag/mol Ag
m(Ag) = 3.8193 mol × 107.868 g/mol = 412 g Ag = 410 g Ag rounded to two significant figures
The mass of 2.3 × 10²⁴ Ag atoms is approximately 410 g.
Answer:
[tex]\boxed {\boxed {\sf 3.8 \ moles \ of \ sulfur}}[/tex]
Explanation:
We are asked to convert a number of atoms to moles.
We can convert atoms to moles using Avogadro's Number, which is 6.022 × 10²³. This is the number of particles (atoms, molecules, formula units, etc.) in 1 mole of a substance. In this problem, the particles are atoms of sulfur. There are 6.022 ×10²³ atoms of sulfur in 1 mole of sulfur.
We use dimensional analysis to convert atoms to moles. This involves setting up ratios. Use Avogadro's Number and the underlined information to make a ratio.
[tex]\frac {6.022 \times 10^{23} \ atoms \ S}{1 \ mol \ S}[/tex]
We are converting 2.3 ×10²⁴ atoms of sulfur to moles, so we multiply by this value.
[tex]2.3 \times 10^{24} \ atoms \ S *\frac {6.022 \times 10^{23} \ atoms \ S}{1 \ mol \ S}[/tex]
Flip the ratio. It is equivalent, but it allows the units of atoms of sulfur to cancel.
[tex]2.3 \times 10^{24} \ atoms \ S *\frac {1 \ mol \ S}{6.022 \times 10^{23} \ atoms \ S}[/tex]
[tex]2.3 \times 10^{24} *\frac {1 \ mol \ S}{6.022 \times 10^{23} }[/tex]
[tex]\frac {2.3 \times 10^{24} }{6.022 \times 10^{23} } \ mol \ S[/tex]
[tex]3.819329127 \ mol \ S[/tex]
The original measurement of atoms (2.3 ×10²⁴) has 2 significant figures, so our answer must have the same. For the number we calculated that is the tenths place. The 1 in the hundredths place to the right (3.819329127) tells us to leave the 8 in the tenths place (3.819329127).
[tex]3.8 \ mol \ S[/tex]
2.3 ×10²⁴ atoms of sulfur is equal to approximately 3.8 moles of sulfur.
Type the correct answer in the box. Express your answer to two significant figures. You are performing a reaction with 1.7 moles of hydroiodic acid and 3.43 moles of zinc bromide: 2HI + ZnBr2 → 2HBr + ZnI2. How many moles of zinc iodide can be made? The theoretical yield is moles of zinc iodide.
Answer:
1.34 34343 he did
Explanation:
i did the test
Answer:
0.85
Explanation:
Volume = 90g / 3g cm3 What is the volume help ASAP
Answer:
The answer will be this 30g/cm3
Is it possible to prepare chlorine in lab without application of heat?
Answer:
i think it will explode
A place where animals are protected in their natural habitat is called ------------------
answer is wildlife sanctuary
Answer:
a wildlife sanctuary
Explanation:
What is required for dynamic equilibrium?
A. A closed system.
B. The forward and backward reactions occur under the same conditions.
C. A reversible reaction.
D. All of these
Answer:
A. all of them
Explanation: Edtell
1. what is hard water.
2. Mention four sources of water.
3. write down the chemical formula of water.
4. What is purification of water.
5. Mention two importance of purification of water.
6. Mention 4 method used ot purify water. 7. Mention 4 impurities found in water.
8. Explain the term contaminated of water.
9. State two physical properties of water. 10. mention the names of of the elements that causes hardness in water.
Answer:
Oh man, the questions are much
Explanation:
1. Hard water is water what has high mineral content. (I can't go into details )
2. River, reservoir, Lake, groundwater, rain
3. H2O
4. POW is the process of removing undesirable chemicals, biological contaminants, suspended solids and gases from water.
5. Reduces amount of chlorine, soil residue, and organic and inorganic substances. Helps in improving the taste. Smell and visual appearance of water.
6. Boiling, filtration, distillation, and chlorination
7. Dust, dirt, harmful chemicals, biological contaminants, radiological contaminants
8. It is the contamination of water bodies, usually as a result of human activities, in such a manner that negatively affects it legitimate uses.
9. Colorless, turbidity, taste And odor.
10. Hardness of water is caused by compounds of calcium and magnesium, and by a variety of other metals.
What are the top three sources of US electricity generation?
The three major categories of energy for electricity generation are fossil fuels (coal, natural gas, and petroleum), nuclear energy, and renewable energy sources.
Which is the best term to use when describing the energy of motion? chemical kinetic potential thermal
Answer:
Kinetic energy
Explanation:
Kinetic energy is the energy associated with an object's motion. It is mass and velocity dependent by a directly proportional relationship.
Potential energy is the energy associated with an object's position.
Thermal energy is the energy associated with heat addition or withdrawal.
Kinetic energy is the energy that a body possesses because of its movement, that is, it is the energy that arises when objects are in motion.
What is kinetic energy?It is that energy that a body or system possesses due to its movement.The amount of work done by all the forces acting on a body with a given mass, depends on the said mass and the speed of the body.Therefore, we can conclude that kinetic energy is the energy produced by its movements that depends on its mass and speed.
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10. Fuel oil, gasoline, kerosene and naphtha are four fractions obtained from the fractional
distillation of petroleum.
What is the order of the boiling points of these fractions?
Answer:
option b
Explanation:
answer from gauth math
Which of the following structures in the human eye most likely functions in a way to help humans see clearly in different levels of light? A. The iris, or the colored portion of the eye
B. The white area
C. The eyelid
D. The pupil, or the dark portion at the center of the eye
D. the pupil or the dark portion at the center of the eye
A student conducts an experiment to determine how the temperature of water affects the time for sugar to dissolve. In each trial, the student uses a different amount of water and a different temperature of water. What is wrong with this experimental design? A.The student changed more than one independent variable. B.The student did not change enough independent variables. C.The student needs to perform more trials. D.The student does not have a dependent variable.
What is wrong with the experimental design is that the student changed more than one independent variable.
WHAT AN EXPERIMENT SHOULD CONTAIN?
An experiment is a procedural method of solving a scientific problem or answering a scientific question. An ideal experiment should contain two variables namely: independent variable and dependent variable. Dependent variable: This is the variable that the experimenter measures in the experiment. The dependent variable responds to changes made to the independent variable. Independent variable: This is the variable that is manipulated in an experiment in order to bring about a response.In the experiment conducted by the student in this question in order to determine how the temperature of water affects the time for sugar to dissolve. The independent variable is the DIFFERENT TEMPERATURE OF WATER while the dependent variable is the TIME TAKEN FOR SUGAR TO DISSOLVE.
N.B: An experiment should have only one independent variable and all other variables should be kept constant. This is to have a reliable result.
However, this student used two independent variables (temperature and amount of water) for the experiment, which is wrong for the experimental design.Therefore, the fact that the student changed more than one independent variable is wrong for the experimental design.
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Answer:
The student changed too many variables.
Explanation:
in k-12 took the quiz
The graph below shows how solubility changes with temperature.
A graph with the horizontal axis showing temperature ranging from 0 to 10 in units of 10 and the vertical axis solubility in grams of salt per 100 grams of water. Several compounds are shown. All data are approximate. The substances and their coordinates are as follows: upper N a upper C l: 0, 38; 10, 38; 20, 38; 30, 38; 40, 39; 50, 39; 60, 39; 70, 40; 80, 40; 90, 40; 100, 40. Upper N a subscript 2 upper H upper A s upper O subscript 4: 0, 5; 10, 18; 20, 28; 30, 39; 40, 49; 60, 65; 80, 82. Upper B a (upper N upper O subscript 3) subscript 2: 0, 5; 10, 8; 30, 12; 40, 15; 50, 18; 60, 20; 80, 28; 100, 33. Upper N a subscript 2 upper S upper O subscript 4: 0, 5; 5, 8; 10, 10; 15, 15; 20, 20; 25, 20; 28, 35; 30, 40; 32, 49; 33, 50; 35, 50; 40, 48; 50, 47; 60, 46; 70, 45; 80, 43; 90, 32; 100, 40. Upper C 3 subscript 2 (upper S upper O subscript 4) subscript 3 dot 9 upper H subscript 2 upper O: 0, 18; 20, 10; 30, 8; 50, 5; 60, 3; 80, 1; 100, 0.
How many grams of NaCl will be needed to form 600 mL of a saturated solution at 100°C?
15 g
24 g
40 g
240 g
answer 240g
The amount of NaCl required to prepare a 600 mL saturated solution depends on the solubility at the temperature.
What is solubility?Solubility is the amount of solute that dissolves in a given volume of solvent.
Solubility = amount of solute/volume of solvent oSolutions may be saturated, unsaturated, super saturated solution.
For solutes, the solubility increases with increase in temperature.
The amount of NaCl required to prepare a 600 mL saturated solution depends on the solubility at the temperature.
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Answer:
240
Explanation:
