Most of these questions relate to the Doppler Effect - how the frequency of sound and light waves changes depending on whether the source is moving towards or away from the observer. Moving toward an observer leads to higher frequencies and a 'blue shift' while moving away leads to lower frequencies and a 'red shift'.
Explanation:1. As an object moves towards another object the sound waves bunch up. True. This is a representation of the Doppler Effect where the frequency appears to change when a source of sound is moving relative to the observer.
2. As an object moves toward another object the sound waves have a lower frequency. False. As the object moves closer, the sound waves will have a higher frequency.
3. As an object moves toward another object the sound waves have a lower frequency. False as explained in the question.
4. Faster sources moving towards an object have a higher pitch than slower-moving sources. True. Faster moving sources will cause the sound waves to bunch up leading to higher frequency and hence greater pitch.
5. An object moving away will have a lower pitch. True. The pitch will appear to be lower as the sound waves are spread out.
6. Lower shows differences in frequency as color. This sentence is not clear enough to provide an accurate response.
7. An object moving away to be blue-shifted. False. An object moving away shows a red shift; a blue shift occurs when an object is moving toward the observer.
8. Is a star that shows as blue-shifted moving toward the observer. True. The blue shift indicates that a cosmos object is moving towards us.
9. Faster-moving objects show MORE shifts in frequency. True. The frequency of light waves will change more noticeably with faster-moving objects due to the Doppler effect.
10. Galaxies appear to be redshifted from observing on Earth. Is this because they are moving towards the earth? False. Galaxies are moving away from the Earth which is why they appear redshifted.
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what is the concentration of a NaCl solution, in Molarity, if you add 59.76 g of NaCl into 270 mL of H2O
Hey there!
Molar mass NaCl = 58.44 g/mol
Number of moles
n = mass of solute / molar mass
n = 59.76 / 58.44
n = 1.0225 moles of NaCl
Volume in liters:
270 mL / 1000 => 0.27 L
Therefore:
M = number of moles / volume ( L )
M = 1.0225 / 0.27
= 3.78 M
Hope that helps!
Express in scientific notation. Choose the answer with the proper number of significant figures. (3 x 104) (4 x 1023) = _____ 1227 12 x 1027 10 x 1027 1 x 1028
You know what number of significant figures is required by what they give you originally. In this case, there is only one. (3x10^4)(4x10^23) = 1.2x10^28. However, this is the answer with two significant figures. Thus, round it to become one sigfig: 1x10^28.
Answer:
1x10^28
Explanation:
Energy transformations that occur when a ball is thrown in the air
The amount of force applied per unit area is known as which of the following?
pressure
power
vector
volume
Pressure is the amount of force applied per unit area perpendicular to the surface, represented by the formula P = F/A, with P being pressure, F the force, and A the area; pressure is measured in pascals (Pa).
The concept in question refers to pressure, which is a fundamental idea in the field of physics. Pressure is defined as the force applied per unit area that is perpendicular to the force. The equation for calculating pressure is P = F/A, where P stands for pressure, F represents the force applied, and A denotes the area over which the force is distributed.
Note that while force is a vector quantity, meaning it has both magnitude and direction, pressure is a scalar quantity. This is because pressure is proportional to the magnitude of the force acting perpendicular to the surface and does not have a direction associated with it. The standard unit for measuring pressure is the pascal (Pa), which is named after the renowned French mathematician and physicist Blaise Pascal.
A scientist collects a core sample from 60 km deep in Earth.
Which characteristic will she most likely observe in this sample?
a. The sample has high iron content.
b. The sample is very hot and liquefied.
c.The sample mainly consists of granite.
d. The sample has a very high density.
Answer. C. The sample will mainly consist of granite.
Explanation:
Sample collected from was continental crust (a part crust) as the samples were from 60 km deep. Continental crust ranges from 30 km to 70 km and this layer is mainly includes granite. This continental crusts is mainly responsible for formation of distinct land-forms like continents.
Statement A ,B and D informs us about the state and temperature of metals(iron) in core that is inner most layer of the earth.
Match the formula for the following compound:
dinitrogen pentoxide
NO
N5O2
N2O5
N3O2
Answer : The correct formula of the compound is, [tex]N_2O_5[/tex]
Explanation :
Dinitrogen pentoxide is a covalent compound in which both the elements nitrogen and oxygen are non-metals.
The formula of covalent compound is given by:
The less electronegative element is written first with prefix number like 'mono' for 1 atom, 'di' for 2 atoms, 'tri' for 3 atoms and so on.... in the subscript.The more electronegative element is written then with their prefix number in the subscript.So, the formula of given compound is, [tex]N_2O_5[/tex]
A gas has a volume of 27.5 L at 302 K and 1.40 atm. How many moles are in the sample of gas?
A. 0.0401 mol
B. 0.645 mol
C. 1.55 mol
D. 2.14 mol
According to ideal gas equation, there are 1.55 moles in the sample of gas.
To calculate the number of moles in a sample of gas, we can use the Ideal Gas Law equation: [tex]PV=nRT[/tex] where P is the pressure of the gas, V is its volume, n is the number of moles, R is the gas constant, and T is the temperature in Kelvin.
We can rearrange the Ideal Gas Law equation to solve for n:
[tex]n=\dfrac{PV}{RT}[/tex]
Given:
V = 27.5 L
T = 302 K
P = 1.40 atm
We can use the gas constant, R, which is 0.0821 L·atm/mol·K.
Plugging in the values:
[tex]n=\dfrac{1.40}{0.0821}[/tex]×[tex]\dfrac{27.5}{302}[/tex]
=1.55 moles
Therefore, the number of moles in the sample of gas is 1.55 moles. Hence, option C is correct.
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The transition metals are involved in:
alloys
coordination complexes
catalysts
all of the above
all of above ! they are involved in all thee mentioned here
Which of the following by hypotheses cannot be tested using the scientific method?
1 . If the temperature is increased , the reaction rate of HCI AND NaOH will increase.
2.Cold weather causes car tires to deflate .
3. The booing of Hiroshima ending world war ll.
4. If students do more homework their grades will improve.
A chemist divides a large sample of a mixture into three smaller portions. Each of these portions contains different ratios of the component substances that make up the mixture. Which description best fits the mixture?
A.
compound
B.
element
C.
heterogeneous mixture
D.
homogeneous mixture
E.
pure substance
Which statement about scientific consensus is true?
A.
It represents the beliefs of most scientists.
B.
It is the only way to prove a theory true.
C.
It is necessary to form a hypothesis.
D.
It is an assurance that the interpretations of a study are correct.
E.
It is necessary before research can be published in a science journal.
1) The answer is: C. heterogeneous mixture.
Heterogeneous mixture is not uniform in composition.
This substance is not element or compound, because different components could be observed in the substance.
Pure substance is made of only one type of atom (element) or only one type of molecule (compound), mixtures and solutions are made from two or more types of pure substances.
For example, aluminium is an element and ammonia is compound.
This substance is not a homogeneous mixture, because different samples of the substance appeared to have different proportions of the components.
2) The answer is: A. It represents the beliefs of most scientists.
Consensus is general agreement, but not necessarily unanimity.
Consensus is achieved through communication at conferences, the publication process, replication and peer review.
For example, 97 percente of scienties agree that climate warming trends over the past century are extremely likely due to human activities.
Examine the information.
A runner travels 10 m/s forward for 10 seconds.
Which of the quantities in the sentence would be considered a vector quantity, and why?
The quantity 10 m/s is the only vector quantity because it is a measurement of speed.
The quantity 10 s is the only vector quantity because it measures time.
The quantity 10 m/s is the only vector quantity because it is a measurement that includes a direction.
The quantities 10 m/s and 10 s are vector quantities because these numbers are both measurements that do not include direction.
Answer:
The quantity 10 m/s is the only vector quantity because it is a measurement that includes a direction.
Explanation:
Vector quantities are physical quantities with both magnitude (size) and direction. Examples of vectors include displacement, velocity, acceleration, force, momentum etc.
Time is a scalar quantity having only size. So 10 s is not a vector. 10 m/s forwards is velocity because of the direction.
What is true of valence electrons?
Question 14 options:
They exist in the outer orbital.
They have difficulty moving from one orbital to another.
They are always the lowest energy electrons of the atom.
They easily move from one orbital to anothe
Answer:They exist at specific energy levels.
Explanation:
The prefix 'kilo-' means a thousand. So a kilo-gram is a thousand grams. 1 kilogram=1,000 grams How many kilograms is 1,008 grams? Round your answer to the nearest tenth of a kilogram.
Answer: 1.0 kilograms.
Explanation:
One kilogram is equal to a thousand grams.
Supposing x to be the number of kilograms equal to one thousand and eight grams, we can write it as:
1 kg = 1000 grams
x kg = 1008 grams
To solve for x, we can simply divide 1008 grams by 1000 thousand grams to get the answer.
x = 1008 / 1000
x = 1.008
Rounding this value to the nearest tenth, it will become 1.0 kilograms.
1,008 grams is equivalent to 1.008 kilograms, and when rounded to the nearest tenth of a kilogram, it is 1.0 kilogram.
To find out how many kilograms 1,008 grams is, we need to convert grams to kilograms. We know that 1 kilogram is equal to 1,000 grams. Therefore, we need to divide the number of grams by 1,000 to convert to kilograms. For 1,008 grams, the calculation is as follows:
1,008 grams / 1,000 = 1.008 kilograms
When rounding to the nearest tenth of a kilogram, we get 1.0 kilograms because the hundredth place is less than 5.
So, the answer is that 1,008 grams is equivalent to 1.0 kilogram when rounded to the nearest tenth.
Which one of the following mixtures is classified as a suspension
Final answer:
A suspension is a heterogeneous mixture where the dispersed particles are large enough to settle upon standing. Mud in water is an example of a suspension because it has large particles that are visible, the mixture is cloudy, and particles settle when undisturbed.
Explanation:
To identify which mixture is classified as a suspension, it's essential to understand the particle sizes involved in different mixtures. A suspension contains particles with diameters around 1 µm (1000 nm) that are dispersed throughout another phase. Examples of suspensions include muddy water and paint. In contrast, colloids involve much smaller particles (2 to about 500 nm in diameter) that do not settle on standing, such as milk or fog.
Considering the information provided, a suspension is a heterogeneous mixture where the dispersed particles are large enough to settle out upon standing. These particles can often be separated from the dispersing medium by filtration. In contrast, a solution has much smaller particles that do not settle and cannot be filtered out.
From the examples provided, mud in water fits the definition of a suspension. The particles are of appropriate size, it's heterogeneous, the mixture is cloudy due to the particles, and it will allow for settling over time if left undisturbed.
Mole Word Problems
The recommended daily allowance of selenium in your diet is 6.97x10-7 mole. How many atoms of selenium is this?
A bracelet containing 0.200 mol metal is 75% gold. How many atoms of gold are in the bracelet?
Which has more atoms, 10.0 g C or 10.0 g of Ca? How many atoms does each contain?
A mixture contains 0.250 mol Fe and 1.20 g C. What is the total number of atoms in the mixture?
Air contains several gases. Argon makes up 0.934% of the air. If a person takes a breath that contains 0.600 g of air, calculate the number of argon atoms inhaled.
A chemist needs 0.015 mol of iodine crystals, I2, for an experiment. What mass of iodine crystals should the student obtain?
BONUS PROBLEM
One atom of an unknown element has a mass of 6.66x10-23 g. What is the identity of this element?
Q: The recommended daily allowance of selenium in your diet is 6.97x10-7 mole. How many atoms of selenium is this?
Answer:4.19 × 10¹⁷ Se Atoms
Solution:As we know that 1 mole of any substance contains exactly 6.022 × 10²³ particles which is also called as Avogadro's Number. So in order to calculate the number of particles (atoms) contained by 6.97 × 10⁻⁷ moles of Se, we will use following relation,
Moles = Number of Atoms ÷ 6.022 × 10²³ Atoms.mol⁻¹
Solving for Number of Atoms,
Number of Atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹
Putting values,
Number of Atoms = 6.97 × 10⁻⁷ mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of Atoms = 4.19 × 10¹⁷ Atoms
++++++++++++++++++++++++++++++++++++++++++++++++++
Q: A bracelet containing 0.200 mol metal is 75% gold. How many atoms of gold are in the bracelet?
Answer:9.033 × 10²² Atoms of Gold
Solution:As we know that 1 mole of any substance contains exactly 6.022 × 10²³ particles which is also called as Avogadro's Number. So in order to calculate the number of particles (atoms) contained by 0.200 moles of Au, we will use following relation,
Moles = Number of Atoms ÷ 6.022 × 10²³ Atoms.mol⁻¹
Solving for Number of Atoms,
Number of Atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹
Putting values,
Number of Atoms = 0.200 mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of Atoms = 1.20 × 10²³ Atoms
For 75%,
Number of Atoms = 1.20 × 10²³ Atoms × 0.75
Number of Atoms = 9.033 × 10²² Atoms of Gold
++++++++++++++++++++++++++++++++++++++++++++++++++
Q: Which has more atoms, 10.0 g C or 10.0 g of Ca? How many atoms does each contain?
Answer:Carbon has greater number of Atoms.
Solution:Data Given:
Mass of Carbon = 10 g
M.Mass of Carbon = 12.01 g.mol⁻¹
Mass of Calcium = 10 g
M.Mass of Calcium = 40.08 g.mol⁻¹
Step 1: Calculate Moles of Carbon as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 10 g ÷ 12.01 g.mol⁻¹
Moles = 0.8326 mol
Step 2: Calculate number of Carbon atoms,
As 1 mole of any substance contains 6.022 × 10²³ particles (Avogadro's Number) then the relation for Moles and Number of Carbon atoms can be written as,
Moles = Number of C Atoms ÷ 6.022 × 10²³ Atoms.mol⁻¹
Solving for Number of C atoms,
Number of C atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹
Putting value of moles,
Number of C atoms = 0.8326 mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of C atoms = 5.01 × 10²³ C atoms
Step 3: Calculate Moles of Calcium as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 10 g ÷ 40.08 g.mol⁻¹
Moles = 0.25 mol
Step 4: Calculate number of Calcium atoms,
As 1 mole of any substance contains 6.022 × 10²³ particles (Avogadro's Number) then the relation for Moles and Number of Calcium atoms can be written as,
Moles = Number of Ca Atoms ÷ 6.022 × 10²³ Atoms.mol⁻¹
Solving for Number of Ca atoms,
Number of Ca atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹
Putting value of moles,
Number of Ca atoms = 0.25 mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of Ca atoms = 1.50 × 10²³ C atoms
++++++++++++++++++++++++++++++++++++++++++++++++++
Q: A mixture contains 0.250 mol Fe and 1.20 g C. What is the total number of atoms in the mixture?
Answer:2.10 × 10²³ Atoms in Mixture
Solution:Atoms in Fe:
As we know that 1 mole of any substance contains exactly 6.022 × 10²³ particles which is also called as Avogadro's Number. So in order to calculate the number of particles (atoms) contained by 0.25 moles of Fe, we will use following relation,
Moles = Number of Atoms ÷ 6.022 × 10²³ Atoms.mol⁻¹
Solving for Number of Atoms,
Number of Atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹
Putting values,
Number of Molecules = 0.25 mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of Molecules = 1.50 × 10²³ Atoms of Fe
Atoms in C:
Step 1: Calculate Moles of Carbon as,
Moles = Mass ÷ M.Mass
Putting values,
Moles = 1.20g ÷ 12.01 g.mol⁻¹
Moles = 0.0999 mol
Step 2: Calculate number of Carbon atoms,
As 1 mole of any substance contains 6.022 × 10²³ particles (Avogadro's Number) then the relation for Moles and Number of Carbon atoms can be written as,
Moles = Number of C Atoms ÷ 6.022 × 10²³ Atoms.mol⁻¹
Solving for Number of C atoms,
Number of C atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹
Number of C atoms = 0.0999 × 6.022 × 10²³ Atoms.mol⁻¹
Number of C atoms = 6.01 × 10²² C Atoms
Total Number of Atoms:
= 6.01 × 10²² C Atoms + 1.50 × 10²³ Atoms of Fe
= 2.10 × 10²³ Atoms in Mixture
Remaining answers are attached.
2. Write the formula for the following covalent compound. pentaphosphorus tetraoxide. Explain how you determined the formula. No credit without and explanation. (5 points)
The formula of pentaphosphorus tetraoxide is P₅O₄
As per the convention of naming chemical compounds - the Prefix names are used for naming covalent compounds.
The prefix 'penta' means '5', so we use 5 as subscript for P.
The prefix 'tetra' means '4', so we use 4 as subscript for O.
Therefore the formula of pentaphosphorus tetraoxide is P₅O₄
Recorded observations are called:
data
information
impressions
feelings
ideas
Which of the following elements in the third period would you expect to have the most negative electron affinity value, and why? Aluminum (Al), because it is a metal with a large atomic radius Chlorine (Cl), because it is a halogen with a high effective nuclear charge Silicon (Si), because metalloids release the most energy when gaining electrons Sodium (Na), because alkali metals only have one electron in the outer energy level
Answer:- Chlorine(Cl)
Explanations:- Electron affinity is the amount of energy released when an electron is added to an element in it's gaseous state. Electron affinity increases in a period on going left to right as the size of the element decreases and it's effective nuclear charge increases and this facilitate an element to accept the electron.
The elements mentioned here in the question belongs to the same group and out of these, chlorine is on the right most side and so it is correct choice.
Hence, Chlorine(Cl), because it is a halogen with a high effective nuclear charge is the correct choice.
The answer is: B) Chlorine (Cl), because it is a halogen with a high effective nuclear charge
What is one characteristic of the groundwater that forms caves? A. It is very hot. B. It is very cold. C. It is slightly acidic. D. It is slightly basic.
Answer: Groundwater that forms caves because it is slightly acidic.
Explanation:
The water under the ground present inside the cracks and spaces in sand, soil and rocks is called ground water.
When ground water moves through the soil it results in the formation of acid. Further, this acid helps minerals to get dissolve. These minerals get deposited on other places as well.
This process of deposition and erosion helps in the formation of caves.
Thus, it can be concluded that groundwater that forms caves because it is slightly acidic.
If many observations or results of experiments fail to agree with your deductive reasoning, then:
the general principle or theory is probably false.
the general principle or theory is probable true.
the general principle or theory is probably false
Most people like to go outside on a sunny day, but too much sun exposure can cause sunburns as well as long term health problems, such as eye damage or skin cancer. How do humans protect themselves from too much sun exposure?
Answer:
all of these
Answer:
all of these
Explanation:
What is the mass of a sample of aluminum that absorbs 596 J of heat when the temperature is raised from 30.0°C to 100.1°C? Specific heat of aluminum = 0.900 J/g oC
Answer is: the mass of a sample of aluminum is 9.45 grams.
ΔT = 100.1°C - 30.0°C.
ΔT = 70.1°C.; change in temperature of a sample of aluminium.
Cp(Al) = 0.900 J/g·°C; specific heat capacity for aluminium.
Q = 596 J; heat absorbed.
Q = m(Al) · ΔT · Cp(Al).
m(Al) = Q ÷ (ΔT · Cp(Al)).
m(Al) = 596 J ÷ (70.1°C · 0.900 J/g·°C).
m(Al) = 9.45 g; mass of aluminium sample.
Electron configuration for Lithium.
The answer to problem is [He] 2s1. Hope it helps
Your answer is [He] 2s1
Hope that helps :)
A sample of gas at 1.10 atm has a volume of 326 mL. What is the new volume if the pressure is changed to 1.90 atm?
Answer
For this we use ideal gas equation which is:
P1V1 = P2V2
P1 = 1.10 atm
V1 = 326 ml
P2 = 1.90
V2 = ?
By rearranging the ideal gas equation:
V2 = P1V1 ÷ P2
V2 = 1.10 × 326 ÷1.90
V2 = 358.6 ÷ 1.90
V2 = 188.7 ml
Which state(s) of matter do not have a definite shape nor volume? A. Liquids only B. Liquids and gases C. Gases only D. Gases and plasmas
C. Gases only
Explanation:Gases are the state of matter that has no definite shape and volume while liquids have no definite shape but have definite volume and solids have both definite shape and definite volume. so the correct option is "C".
The requirements of atoms to be able to participate in hydrogen bonding with a hydrogen atom include
all of the following except
A. atoms must have one lone pair of electrons.
B. atoms must be electronegative.
C. atoms must be small.
D. atoms must not be able to closely approach the hydrogen.
Answer: C. atoms must be small.
Explanation: Hydrogen bond is the result of the electrostatic forces of attraction between the hydrogen and the electonegative atom. It is a type of dipole dipole interaction which is not so much of a covalent bond.
The options A, B and D satisfies the definition of the hydrogen bonding but the option C seems to be irrelevant as hydrogen bonding does not deal with the size of the atom.
Thus for the hydrogen bonding , the other atom must be electronegative, and atoms must have atleast one lone pair of electrons and atoms must not be able to closely approach the hydrogen.
The compound copper(ii) nitrate is a strong electrolyte. write the reaction when solid copper(ii) nitrate is put into water:
When solid copper(II) nitrate is dissolved in water, it breaks down into copper(II) ions and nitrate ions. This process is represented by the balanced chemical equation: Cu(NO3)2 (s) -> Cu^2+ (aq) + 2 NO3^- (aq).
Explanation:When solid copper(II) nitrate, denoted as Cu(NO3)2, is put into water, it dissociates into its ions. The balanced chemical reaction is represented as follows:
Cu(NO3)2 (s) -> Cu^2+ (aq) + 2 NO3^- (aq)
Here, (s) stands for solid, while (aq) means aqueous, i.e., ions dissolved in water. Copper(II) nitrate breaks down into copper(II) ions (Cu^2+) and nitrate ions (NO3^-). Because copper(II) nitrate is a strong electrolyte, it dissociates completely in water, meaning there are no leftover solid particles floating in the solution, just a solution of the individual ions.
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how interactions cause substance to boil at different tempurtures
About 300 B.C., Aristarchus suggested that the sun was at the center of the universe. Why?
The brightness of the planets would change.
The planets appeared to move among the constellations.
The planets always moved opposite to the stars.
The planets disappeared periodically.
The correct answer is option A and B
About 300 B.C., Aristarchus suggested that the sun was at the center of the universe because a) the brightness of the planets would change and b) the planets appeared to move among the constellations.
18 centuries before Copernicus, Aristarchus predicted that all planets orbit the sun. In other words, he suggested the Solar System is heliocentric.
Answer:
the answer is A And B
Explanation:
just took the test
Read the scenario.
A lizard is at an initial position of 2 m and walks to a position of 10 m in 4 s.
What is the lizard’s average velocity?
2.5 m/s
-3 m/s
2 m/s
3 m/s
The answer is C. 2 m/s
Answer: 2m/s
Explanation:
Initial position = 2m
Final position = 10m
Distance = 10-2 = 8m
Time = 4s
Velocity = distance(m) /time(s)
Velocity = 8/4 = 2m/s