Answer:
109°
Explanation:
According to Valence Shell Electron Pair Repulsion Theory, electron pairs on the valence shell of the central atom of a molecule must be positioned as far apart in space as possible to minimize repulsion between valence shell electron pairs.
The shape of a molecule depends on the number and type of electron pairs on the valence shell of its central atom. Lone pairs generally cause more repulsion than bond pairs of electrons.
The ideal bond angle for a molecule with four bonds is 109° which corresponds to a tetrahedral geometry. This enables the four bonds to spread as far apart in space as possible.
Why do fireworks produce different colors
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Energy is the only factor that determines the color of light of fireworks.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
Fireworks has many different types of element. When any element is given an energy. Then the process of excitation of electrons takes place from its outermost shells. Every element absorb characteristic wavelength of energy and releases light to the corresponding wavelength.
Therefore, energy is the only factor that determines the color of light of fireworks.
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Select the answer from the drop-down, ranging from true or false.
Mixtures have components that are always in fixed ratios.
[ true or false ]
Compounds can only be separated physically.
[ true or false ]
The components of a mixture keep their unique properties.
[ true or false ]
Mixtures can be physically separated
[ true or false ]
Mixtures are pure substances
[ true or false ]
Compounds are pure substances
[ true or false ]
Answer:
False, False, True, True, False, True
Explanation:
Mixtures have components that are always in fixed ratios. FALSE. The ratio of components in a mixture is variableCompounds can only be separated physically. FALSE. Compounds can only be separated chemically.The components of a mixture keep their unique properties. TRUE. Mixtures can be physically separated. TRUE. Mixtures are pure substances. FALSE. Mixtures are formed by a mixture of 2 or more pure substances, not bonded chemically.Compounds are pure substances. TRUE.true? no false. ... no its true uhhhhh no gotta be false true. false. true. fase. gotta be tru false or maybe its true? nah its false
pls brainliest?
How many sig figs are there
5.00000008
Answer:
2 sig figs.
Explanation:
Sig Fig Rules:
Any non-zero digit is a significant figure.
Any zeros between 2 non-zero digits are significant figures.
Trailing zeros after the decimal are significant figures.
An unknown substance from planet X has a density of 10 g/ml. It occupies a volume of 80 ml. What is the mass of this unknown substance? *
Answer:
The answer is
800 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
density = 10 g/ml
volume = 80 ml
The mass of the substance is
mass = 10 × 80
We have the final answer as
800 gHope this helps you
The density of water at 40°C is 0.992 g/mL. What is the volume of 2.69 g of water at this temperature? V= mL
Answer:
[tex]\boxed {\tt 2.71169355 \ mL}[/tex]
Explanation:
Density can be found using the following formula:
[tex]d=\frac {m}{v}[/tex]
Rearrange the formula for v. Multiply both sides by v, then divide both sides by d.
[tex]d*v =\frac {m}{v}*v[/tex]
[tex]d*v=m[/tex]
[tex]\frac{d*v}{d}=\frac{m}{d}[/tex]
[tex]v=\frac{m}{d}[/tex]
The volume can be found by dividing the mass by the density. The mass is 2.69 grams and the density is 0.992 grams per milliliter.
[tex]m= 2.69 \ g\\d= 0.992 \ g/mL[/tex]
Substitute the values into the formula.
[tex]v=\frac{2.69 \ g}{0.992 \ g/mL}[/tex]
Divide. Note that the grams, or g, will cancel each other out.
[tex]v=\frac{2.69}{0.992 \ mL}[/tex]
[tex]v= 2.71169355 \ mL[/tex]
The volume of the water is 2.71169355 milliliters.
Which common item is made from copper?
soap
coins
baby powder
colored pencils
Answer:
coins
Explanation:
Complete the chemical combustion reaction of naphthalene, which
demonstrates the conservation of mass.
C10H8 + 1202 >>
Answer:
[tex]C_{10}H_{8}+12O_2\rightarrow 10CO_2+4H_2O[/tex]
Explanation:
Hello,
In this case, since combustion reactions yield carbon dioxide and water via the following equation:
[tex]fuel+O_2\rightarrow CO_2+H_2O[/tex]
In such a way, for naphthalene, its combustion reaction is:
[tex]C_{10}H_{8}+12O_2\rightarrow 10CO_2+4H_2O[/tex]
Whereas we see ten carbon atoms, eight hydrogen atoms and twenty four oxygen atoms at both reactants and products as a proof of the law conservation of mass.
Regards.
Students observed cells under the microscope. They observed that the cells had a cell wall, cell membrane,
nucleus, and many chloroplasts.
Which observation helps students identify the type of cell observed?
A The presence of a nucleus means the cells are from a plant.
B The presence of a cell membrane means that the cells are from an animal.
C The presence of chloroplasts means that the cells are from a plant.
D The presence of a cell wall means that the cells are from an animal.
Answer:
option B is the right answer
which of the following is not true about water ? *
Water has a freezing point of 0℃
Water is chemically stable and makes a good energy source
Water has a density of 1 g/mL
water is polar
water has a boiling point of 100℃
Water is less dense as a solid
Which of these statements is supported by the results of Thomson’s experiment? Check all of the boxes that apply.
Atoms are indivisible.
Cathode rays are made up of negatively charged particles.
Atoms contain negatively charged particles.
Answer: Cathode rays are made up of negatively charged particles.
Atoms contain negatively charged particles.
Express 2.99 x 108 m/s (the speed of light) in decimal notation (i.e., express the
number without using scientific notation
Answer:
speed of light = 299,000,000 m/s
Explanation:
The speed of light in vacuum, denoted as c, is a universal physical constant which unlike space and time, is independent of the observer. It is a constant that is important in many fields of science. Its exact value is given as 299,792,458 metres per second.
In scientific notation, it is approximately given as 2.99 x 10⁸ metres per second.
2.99 x 10⁸ metres per second = 2.99 x 100000000 = 299,000,000 m/s
Therefore, when expressed in decimal notation, the speed of light = 299,000,000 m/s.
What is heat?
O Fire
O Hot
O Energy
O Potential
Answer:
Energy
Explanation:
Heat is a form of energy.
what were the limitations of Dobereiner's classifcation?
Answer:
Dobereiner could find only three triads; . i.e total of 9 elements only. However the total number of elements were more than that of those encompassed in Dobereiner's Triad
Explanation:
Answer:
Dobereiner could find only three triads; . i.e total of 9 elements only. However the total number of elements were more than that of those encompassed in Dobereiner's Triad. Thus, Dobereiner's could not be classify most of the elements known at that time
Explanation:
This work is not my own.... copied from google but hope this helps you.
A peregrine falcon dives 176 meters through the air in 8 seconds. Its
average speed during the dive is 22 m/s. *
Answer:
This question is asking to find the average speed during the dive. The answer is 22m/s.
Explanation:
Average speed of a substance can be calculated knowing it's distance over a particular amount of time.
The formula for average speed is:
Average speed (s) = Distance (d) / time (t)
In the case of this question where A peregrine falcon dives 176 meters through the air in 8 seconds, the distance of the falcon is 176m, while the time is 8s. Hence;
Average speed = 176/8
Average speed = 22
Therefore, the average speed of the falcon diver is 22m/s.
How do the key results indicate
Suppose you are given samples of pentane, 2,2-dimethylpropane, 2-methylbutane and hexane. how you would go about determining which substance had the highest boiling point.
Answer:
Addiction
Explanation:
13 C4- has _______ electrons.
Answer:
10 electrons
Explanation:
A 0.500 g sample of tin (Sn) is reacted with oxygen to give 0.534 g of product. What is the empirical formula of the oxide?
Answer:
[tex]Sn_2O[/tex]
Explanation:
Hello,
In this case, given the mass of the sample and mass of tin we can compute the mass of oxygen via:
[tex]m_O=0.534g-0.500g=0.034g[/tex]
Thus, by using the atomic bas of tin and oxygen we can compute their moles:
[tex]n_{Sn}=0.500gSn*\frac{1molSn}{118.8gSn} =0.00421mol\\\\n_O=0.034gO*\frac{1molO}{16gO}=0.002125mol[/tex]
Next, we need to divide both moles by the moles of oxygen as those are the smallest in order to compute the subscript in the chemical reaction:
[tex]Sn=\frac{0.00421}{0.002125}=2\\ \\O=\frac{0.002125}{0.002125}= 1[/tex]
Therefore, empirical formula of the oxide should be:
[tex]Sn_2O[/tex]
Best regards.
How many Calories are there in 4600 Joules?
Answer:
1099.426
Explanation:
Why are atoms usually portrayed as spheres when most orbitals are not spherically shaped?
a. The shape of an atom depends on the shape of its nucleus, not on the shape of its orbitals.
b. The shape of an atom depends on the shape of the outer orbital which always spherical
c. The shape of an atom is obtained by superimposing all of its orbitals.
d. The shape of an atom is not important so it is easier to treat atoms as spheres.
Answer:
The shape of an atom is not important so it is easier to treat atoms as spheres.
Explanation:
In considering the shape of an atom, we do not consider the shape of the orbitals individually.
Hence, we do not seek to determine the exact shape of the atom, rather we simply treat the atom as spheres. Even though most orbitals are not spherically shaped.
Making a Lis changing something to improve your work. A) scenario
B) revision
C) entry event
D) wish list
why is a lot of energy needed to break covalent bonds
Answer:
The strength of a bond between two atoms increases as the number of electron pairs in the bond increases.
Explanation:
Which of the following is equal to an impulse of 18 units?
O A. Force = 10, time = 2
B. Force = 0.1, time = 18
O C. Force = 6, time = 3
OD. Force = 7, time = 3
Answer:
the answer is C. this is because 6 times 3 is 18
What is the answer? Please
Answer:
true
Explanation:
what is the answer? please
A factor that does no change in an experiment is the.
a. Controlled variable
b. Data
c. Inconstant
d. Independent variable
Answer:
A. Controlled variable
Explanation:
a controlled variable or a constant variable is a variable that doesnt change during an experiment
From a 2.875 g sample containing only iron, sand, and salt, 0.660 g of iron and 1.161 g of sand were separated and recovered. What was the percent of salt in the original sample
Answer:
36.66%
Explanation:
Step 1: Given data
Mass of iron: 0.660 gMass of sand: 1.161 gMass of the sample: 2.875 gMass of salt: ?Step 2: Calculate the mass of salt
The mass of the sample is equal to the sum of the masses of the components.
m(sample) = m(iron) + m(sand) + m(salt)
m(salt) = m(sample) - m(iron) - m(sand)
m(salt) = 2.875 g - 0.660 g - 1.161 g
m(salt) = 1.054 g
Step 3: Calculate the percent of salt in the sample
We will use the following expression.
%(salt) = m(salt) / m(sample) × 100%
%(salt) = 1.054 g / 2.875 g × 100% = 36.66%
The percent of salt in the original sample containing only iron, sand, and salt is 36.66%.
What is salt?Salt is a mineral made up of primarily sodium chloride.
Seawater contains a vast amount of salt.
Given,
The total mass of the sample is 2.875 g
Mass of iron is 0.660 g
Mass of sand is 1.161 g
Step 1: To find the mass of salt
The total mass of the sample = the sum of the masses of the compounds
m(sample) = m(iron) + m(sand) + m(salt)
2.875 g = 0.660 g + 1.161 g + m(salt)
m(salt) = 2.875 g - 0.660 g - 1.161 g
m(salt) = 1.054 g
Step 2: Calculate the percent of salt in the sample
[tex]\%(salt) = \dfrac{m(salt) }{m(sample)} \times 100\%\\\\\\\%(salt) = \dfrac{1.054 g }{2.875 g} \times 100\% = 36.66\%[/tex]
Thus, the percentage of salt in the sample is 36.66%.
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Convert a speed of 933 cm/s to units of inches per minute
Answer:
220000 in/min
Explanation:
Step 1: Write out conversions
1 in ≈ 2.54 cm
60 sec = 1 min
Step 2: Set up dimensional analysis
[tex]\frac{933cm}{s} (\frac{60s}{1min} )(\frac{1in}{2.54cm} )[/tex]
Step 3: Evaluate
220039.4 in/min
Step 4: Sig figs
There are 3 sig figs
220039.4 in/min ≈ 220000 in/min
PLEASE HELP(DUE IN 10 Minuets)
Complete hydrolysis of a hexapeptide gives 2 Gly, Leu, Phe, Pro, and Tyr. Reaction of the peptide with phenylisothiocyanate gave the phenylthiohydantoin of Pro. Partial hydrolysis of the peptide gave the following fragments: Phe-Gly-Tyr, Gly-Phe-Gly, Pro-Leu-Gly, Leu-Gly-Phe. What is the structure of the peptide
Answer:
The complete sequence : Pro-Leu-Gly-Phe-Gly-Tyr
Explanation:
For the formation of phenylisothiocyanate, the four peptide sequences overlap common residue to get the the complete sequence of the hexapeptide as shown in the diagram attached below
Attached below is the structure of the peptide
substance A is a nonpolar liquid and has only dispersion forces among its constituent particles. Substance B is also a nonpolar liquid and has about the same magnitude of dispersion forces among its constituent particles as substance A. When substance A and substance B are combined, they spontaneously mix. Why
Explanation:
The substance A and B will mix into one solution as it is a solvent interactions which is greater than or equal to the solute- solute and the solvent-solvent interactions. Thus when such interactions occurs, it is greater or equal to the some of the other two possible interactions. And here both have the same kind of interaction, and same magnitude, so they will makes to form a solution and mixes properly and spontaneously.