Answer:
The sharing of valence electrons
Explanation:
A covalent bond is formed when two or more atoms share valence electrons.
In BeCl2, electrons are shared between the beryllium atom and two chlorine atoms.
Owing to the large difference in electronegativity between the two elements, the bond is polar covalent.
2. Calculate the density of a rock that has a mass of 21.58 grams and causes the water in a
graduated cylinder to rise from 20.0yl to 25.4 ml.
Answer:
4.00 g/mL
Explanation:
Density is mass divided by volume (g/mL).
Mass of rock = 21.58
Volume of rock = 25.4 - 20.0 = 5.4mL
Density of rock = 21.58g / 5.4mL = 3.99629 g/mL
Round to the lowest number of significant figures which is three = 4.00 g/mL
Part 1)
There is a storage container with 5.25 tons of Ammonia (NH3). How many molecules of Ammonia are there?
Answer:
1.69×10²⁹ molecules.
Explanation:
The following data were obtained from the question:
Mass of Ammonia (NH3) = 5.25 tons
Molecules of Ammonia (NH3) =.?
Next, we shall convert 5.25 tons to grams (g). This can be obtained as follow:
1 ton = 907184.74 g
Therefore,
5.25 ton = 5.25 ton × 907184.74 g / 1 ton
5.25 ton = 4762719.885 g
Therefore, 5.25 tons is equivalent to 4762719.885 g
Finally, we shall determine the number of molecules of ammonia, NH3 in 4762719.885 g. This can be obtained as follow:
From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules. This implies that 1 mole of ammonia, NH3 also contains 6.02×10²³ molecules.
1 mole of ammonia, NH3 = 14 + (3x1) = 14 + 3 = 17 g
17 g of ammonia, NH3 contains 6.02×10²³ molecules.
Therefore, 4762719.885 g of ammonia, NH3 will contain = (4762719.885 × 6.02×10²³) / 17 = 1.69×10²⁹ molecules.
From the calculations made above,
5.25 tons (4762719.885 g) of ammonia, NH3 contains 1.69×10²⁹ molecules.
1.) Electromagnetic waves that you can see are called:
A) Ultraviolet rays
B) microwaves
C) visible light
D) infrared rays
2.) These waves have the longest wavelength and the lowest frequency.
A) infrared waves
B) radio waves
C) microwaves
D) gamma rays
3.) Which wave has high enough energy to cause damage to skin and sometimes cancer?
A) Ultraviolet rays
B) microwaves
C) visible light
D) infrared rays
4.) Waves with high frequency have a ___________ wavelength
5.)Electromagnetic waves are _________ waves, the energy of the wave moves at right angles to the direction of travel.
6.) Which type of wave travels faster in a vacuum: visible light or radio waves? Explain your answer.
7.) What Electromagnetic wave has the highest frequency? What does that mean about the energy of this type of wave?
8.) Mechanical waves like sound require a medium to travel. Are electromagnetic waves mechanical waves? Why or Why not?
9.) Identify each type of electromagnetic wave from the illustration.
(The photo comes with this question)
Do 2. A student determines that there are 1.3 x 1025 molecules of an unknown
substance in a 968 g sample. Which compound most likely represents this
unknown substance?
CO
CIO
2)
CO2
N203
CLEAR ALL
Answer:
The correct option is;
CO₂
Explanation:
The given information are;
The number of molecules in the substance = 1.3 × 10²⁵
The mass of the substance = 968 g
Therefore, we have;
The number of molecules in one mole of a substance = 6.02 × 10²³
The number of moles present = (1.3 × 10²⁵)/(6.02 × 10²³) ≈ 21.595 moles
Therefore, 968 g = 21.595 moles
1 mole = 968/21.595 = 44.826 g
The mass of one mole of the substance = 44.826 g
Therefore the mass of one mole of the substance is closely related to the mass of one mole of CO₂ which is 44.01 g/mol.
The correct option is CO₂
The calculation is as follows:The number of molecules in one mole of a substance should be = 6.02 × 10²³
And,
The number of moles present is
= (1.3 × 10²⁵)/(6.02 × 10²³)
≈ 21.595 moles
Now
1 mole = 968/21.595 = 44.826 g
The mass of one mole of the substance = 44.826 g
So, the mass of one mole of the substance is closely related to the mass of one mole of CO₂ i.e. 44.01 g/mol.
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Do it for 60 points pleaseee
Answer:
period number
Answer:
Period number
Explanation:
Period number is the answer.
Hope this is right!
What are alkali metals
Answer:
Alkali metals are highly reactive elements that appear to be silver and they are found in group 1 of the periodic table. It consists of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). As you go further down the group, the more reactive they are. Those elements all react to water and air, so they must be kept in oil to preserve their state.
how many picoliters are in 3.16 mL
Answer:
3.16×10⁹ pL
Explanation:
Given data:
Volume in mL = 3.16
Volume in picoliters = ?
Solution:
Picoliter and milliliters are units of volume. Milliliter is greater unit than picoliter.
1 mL = 10⁹ pL
Now we will convert the 3.16 mL into pL.
3.16 mL × 10⁹ pL/ 1 mL
3.16×10⁹ pL
Type the correct answer in each box.
Which chemical symbols will complete the equation for this single displacement reaction?
2NaBr + Cl2 → 2 __ __ + __ 2
Answer:
2Naci+Br2
Explanation:
i hope it is help full
Answer:
Na//Cl//Br
Explanation:
What is an ionic bond?
Answer:
Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion
Explanation:
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A large marble is dropped in a graduated cylinder with 45 mL of water in it. The water level increased to 61 mL. What is the volume of the marble?
Answer:
The answer is 16 mLExplanation:
The volume of the marble can be found by using the formula
volume = final volume of water - initial volume of water
So we have
volume of marble = 61 - 45
We have the final answer as
16 mLHope this helps you
Answer:
16mL
Explanation
Which of the following is a CORRECT statement?
Chemical change cannot be undone or reversed.
Physical change often cannot be undone or reversed.
In chemical change, you end up with the same substance you started with.
In physical change, particles of 2 or more substances rearrange to form new or different substance.
Answer:
Detail is given below.
Explanation:
1) Chemical change cannot be undone or reversed.
The given statement is correct. Because,
Chemical change:
The changes, that occur due to change in the composition of a substance and result in a different compound is known as chemical change.
These changes are irreversible .
Example:
Combustion of fuel or wood: that oil or wood convert into energy, CO2 and ash in case of wood and this reaction can not be reversed.
2) Physical change often cannot be undone or reversed.
The given statement is incorrect.
Physical Change
The changes that occur only due to change in shape or physical properties but their chemical or internal composition remain unchanged.
These changes were reversible.
Example :
Water converting to Ice
Water converting to gas
3) In chemical change, you end up with the same substance you started with
The given statement is incorrect. Consider the following example.
The reaction of Hydrogen and oxygen:
H₂ (g) + O₂ (g) -------------------------------------> 2H₂O (l)
A totally new compound is formed when oxygen and hydrogen are undergo reaction which is water.
4) In physical change, particles of 2 or more substances rearrange to form new or different substance.
The given statement is incorrect.
When particles rearrange them selves the different substance is not formed. Consider the example of water when it converted into ice or vapors. Only phase is changed but water retain its properties so new substance is not formed.
A neutral (net charge
zero) atom of silicon contains:
A
28.09 electrons
B
16 electrons
C
14 electrons
D
38 electrons
Answer:
C 14
Explanation:
Silicon atom has 14 protons. Given that a positive and a negative neutralize each other you need 14 electrons to neutralize the 14 protons.
Which quantum number describes the orientation of an orbital within a sublevel?
Explanation:
Each orbital within a particular sublevel is distinguished by its value of ml. This quantum number may be more aptly named the orbital orientation quantum number. In each energy sublevel (designated by l) there are 2l+1 possible independent orientations of the electron cloud.
Answer:
[tex]m_l-magnetic[/tex]
Explanation:
The principal energy level, n, tells us which shell it is in and the total energy of the electron.
The angular momentum (azimuthal), l, tells us which sublevel/subshells the electron is in.
The magnetic, m sub l, tells us the orientation the electron is spinning.
Use the rules of significant figures to report the answer to this math question: (5.003 x 10^4) - (6.059 x 10^3) + (9.23 x 10^2) =
Answer:
44894
Explanation:
The bright red line from the emission spectrum of hydrogen has a wavelength of 657 nm. What is the energy, in joules, of a single photon of this light? 4.35 x 10–40 J 3.03 x 10–28 J 3.03 x 10–19 J 4.56 x 1014 J
Answer:
3.03 × 10^-19 J
Explanation:
The energy, E, of a photon of light can be calculated by using the formula:
E = hv
Where; E is energy in Joules,
h is Planck's constant {6.626×10^−34J}
v is frequency of light
For this question, the wavelength (λ) is given, not the frequency (v).
Hence, we use;
v= c/λ
Where v= frequency, c= speed of light (3×10^8m/s), λ= wavelength (657nm)
657nm = 657 × 10^-9m
v = 3×10^8/657 × 10^-9
v = 3/657 × 10^(8--9)
v = 0.00456 × 10^17
v = 4.56 × 10^14
Since frequency (v) = 4.56 × 10^14;
E = hv
E = 6.626×10^−34 × 4.56 × 10^14
E = 30.21 × 10^(-34+14)
E = 30.21 × 10^-20
E = 3.021 × 10^-19
Therefore, the energy of the photon of light is 3.02 × 10^-19 J
A student has a container of sand and sugar. What characteristic could be used to separate the mixture?
Answer:
Sugar will dissolve, so water.
Explanation:
Sugar is a bicubacle food source you could say, sand will not evaporate or dissolve in the water since it is not a 3c2e source. Using water will seperate them.
Answer: Heat
Explanation:
Because is you put water and sand in a container you can separated by boiling the water and all the water would evaporate and the sand would stay.
What is an atomic theory?
What is an isotope?
How is the atomic mass of an element calculated?
Answer:
Atomic theory is the scientific theory that matter is composed of particles called atoms.
isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number.
to calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons.
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Explanation:
Which properties change the composition of a substance?
A chemical properties
B physical properties
C neither chemical nor physical properties
D chemical and physical properties
Answer:
D. Chemical and physical properties
Which best explains the process of meiosis?
Meiosis includes cytokinesis, which divides the cell's DNA.
Meiosis is a series of steps that divides the cell's cytoplasm.
Meiosis includes interphase, which divides the cell's cytoplasm.
Meiosis is a series of steps that divides the cell's DNA.
Answer:
D
Explanation:
Meiosis is a series of steps that divides the cell's DNA best explains the process of meiosis. Therefore, option D is correct.
What is meiosis ?A type of cell division in which each daughter cell receives half the DNA of the parent cell. In mammals, meiosis occurs during the formation of egg and sperm cells.
Due to the fact that cell division occurs twice during meiosis, a single starting cell can produce four gametes (eggs or sperm). Cells go through four stages during each round of division: prophase, metaphase, anaphase, and telophase.
Meiosis is also important for allowing genetic diversity and facilitating the repair of genetic defects via recombination.
Daughter cells are diploid after meiosis and have twice as much genetic material, which can be divided in an infinite number of ways.
Thus, option D is correct.
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How do you think chemical change is defined?
Answer:
A chemical change happens when one chemical substance is transformed into one or more different substances,
Explanation:
Which of these is a physical change in shape?
A. Digesting food
B. Cooking an egg
C. Breaking a glass
D. Dissolving salt
A student places a small amount of water in a glass dish and then carefully places a small paperclip on the surface of the water. The paperclip floats. What happens if the student adds a drop or two of dish soap to the water?
Answer:
Adding soap would cause the paper clip to fall through the water and onto the base of the dish because soap is a surfactant.
Explanation:
The concept surface tension is used here to determine what happens to the paperclip when a drop of dish soap is added to the water. Here the paperclip sink into the water.
What is surface tension?The property exhibited by the surface of a liquid in order to resist the action of an external force because of the cohesive nature of the molecules is known as the surface tension. Due to this property the surface of a liquid behaves as an extended elastic membrane.
The paperclip float on water because of the high surface tension as the water molecules at the surface are strongly attracted among themselves. But on adding one or two drops of dish soap to water causes the paperclip to sink.
The addition of the drops of dish soap to the water weakens the attraction among the water molecules and thereby lowers the surface tension. As a result of this the surface film disappears and the paperclip sink into the water.
Thus the paperclip fall into the water when a drop of dish soap is added to the water.
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Please help!!!
When 38 g of a metal at 92 °C is added to
43 g of water at 22°C, the temperature of the
water rises to 30°C. What is the specific heat
capacity of the metal? Assume no heat was
lost to the surroundings.
Answer in units of
J/g degrees C
The specific heat capacity of the metal : 0.610 J/g° C
Further explanationThe law of conservation of energy can be applied to heat changes, i.e. the heat received/absorbed is the same as the heat released
Q abs = Q received
Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
∆T = T(final temp) - T(initial temp)
mass of metal = 38 g
T initial metal = 92 °C
mass of water = 43 g
T final water = 30 °C
T initial water = 22°C
c water = 4.18 J/g° C
Heat absorbed by water[tex]\tt Q=m.c.\Delta T\\\\Q=43\times 4.18\times (30-22^oC)\\\\Q=1437.92~J[/tex]
the specific heat capacity of the metalQ water = Q metal
[tex]\tt 1437.92=38\times c\times (92-30)\\\\c=0.610~J/g^oC[/tex]
please help.
In 1976, an airplane was flown at a speed of 2193 miles per hour. How many kilometers could the plane fly in 4.3 hours? Use D.A. with these conversion factors: 1mile = 5280ft 1ft =12 inches 1 inch = 2.54cm
Answer:
9429.9
Explanation:
periodt
Once upon a time, Walter the water molecule was traveling around Linda's blood. He was enjoying moving around wherever he wanted. One day, Walter decided to visit some cells. He traveled in and out of the cells as he pleased. Walter decided that he liked the cells so much that he wanted to stay inside and rest in the vacuole. However, as the day went on, Walter felt a change happening around him. Linda had eaten some VERY salty popcorn. Walter LOVED Sally the salt molecule and felt a magnetic attraction to her. The closer the salt came to the cell, the quicker Walter's love for Sally pulled him out of the cell and towards the salt.
Answer:
This story that is related to the movement of water in relation to the amount of solute seeks to explain the process of OSMOSIS in a very interesting way.
Explanation:
The OSMOSIS process is a process where water diffuses from a compartment with fewer solutes to one with higher solutes, that is why the osmotic intention is to balance the concentrations and molarities between both compartments, this is called osmotic balance.
For this to happen, a highly water-permeable barrier is needed.
Requires a medium to travel (travel fastest through solid-like metal train tracks A Waves B Sound Waves C Light Waves D matter
Answer:
b
Explanation:
becuase of sound waves
_________ are elements of the same element that have a different _______________ due to a different number of _____________.
Answer: Isotopes
Explanation:
The atoms of a chemical element can exist in different types. These are called isotopes. They have the same number of protons (and electrons), but different numbers of neutrons. Different isotopes of the same element have different masses.
Hope this helps!
What are natural resources
Answer:
resources that come from the ground or eath naturally which also means that those minerals like coal take hundreds of years to be created
Percent occurrence and isotope masses for oxygen: 99.759 % at 15.99491 amu, 0.037% at 16.99913 amu and 0.204% is at what amu value, if the average atomic mass is 15.99937 amu?
Show work
Answer:
15.99937 is the value of this question answer
What was Wegener's continental drift idea?
Answer: In the early 20th century, Wegener published a paper explaining his theory that the continental landmasses were “drifting” across the Earth, sometimes plowing through oceans and into each other.
Explanation: He called this movement continental drift.