Answer:
a i believe
Explanation:
a
Which further observation led Mendeleev to create the periodic table
Answer:
Mendeleev realized that the physical and chemical properties of elements were related to their atomic mass in a 'periodic' way, and arranged them so that groups of elements with similar properties fell into vertical columns in his table.
Explanation:
An unknown substance has a volume of 2 cm3 and a mass of 38.6 grams.
What is the density of the sample?
Answer:
The answer is 19.3 g/cm³Explanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question we have
[tex]density = \frac{38.6}{2} \\ [/tex]
We have the final answer as
19.3 g/cm³Hope this helps you
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
what is 1.23 x 10^-3 in standard notation
Answer:
=0.00123
Explanation:
Look at the attachments below
Hope this helps (:
Answer:
0.00123
Explanation:
Standard notation is the normal way of writing numbers. Examples include 1, 2, and 10. The number 1.23 x 10^-3 is written in scientific notation. The decimal goes after the first nonzero integer and it is multiplied by a power of 10. The power or exponent attached to the 10 tells you how many places over you need to move the decimal to get back into scientific notation. Examples include 1.00 x 10^2 (representing 100 in standard form because you would move the decimal two places to the right.), 2.0 x 10^1 (representing 20 in standard form because you would move the decimal one place to the right), and 3.0 x 10^-4 (representing 0.0003 in standard form because you would move the decimal four places to the left since it is a negative exponent).
The negative (-3) exponent in 1.23 x 10^-3 indicated to move the decimal three places to the left. If it was positive, you would move it three places to the right.
In 1.23 x 10^-3 move the decimal to the left 1 place to get:
0.123
two places to get:
0.0123
and a third place to get:
0.00123
The final answer is 0.00123
In which situation is it better to have low friction?
Choose the correct answer.
a skydiver uses a parachute
a student walks down a hallway
a ladder leans against the wall
a hockey puck slides toward the goal
Answer: D- a hockey puck slides toward the goal
Explanation:
It needs to be able to slide easily and thats the correct answer on the test
What is the mass, in grams, of 0.450 moles of Sb?
Answer:
54.9 g
Explanation:
0.450 mol x 122g/mol
Relative and average atomic mass both describe properties of an element related to its different isotopes. Out of these two Relative atomic mas is more accurate. Therefore, 54.9 g is the mass in grams of 0.450 moles of Sb.
What is mass?Mass defines the quantity of a substance. It is measured in gram or kilogram. Average mass is the mass of atoms of an element that are isotopes. It can be calculated by multiplying mass of a isotope to natural abundance of that isotope.
Average atomic mass = (mass of first isotope× percent abundance of first isotope)+(mass of second isotope× percent abundance of second isotope)
Mass of Sb= number of moles of Sb ×Molar mass of Sb
=0.450 mol x 122g/mol
=54.9 g
Therefore, 54.9 g is the mass in grams of 0.450 moles of Sb.
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3. Which of the following is not a compound?
water
potassium iodide
B
sodium chloride
D hydrogen
Plowing is an example of what Energy?
a. Kinetic Energy
b. Potencial Energy
Answer:
mechanical or kinetic eg hammer and nails
Question 2 of 10
What are Van der Waals forces?
A. Forces that change polar molecules into nonpolar molecules
B. Very strong forces that exist between two different molecules
O c. Hydrogen bonds in nonpolar molecules caused by a permanent
dipole
D. Small dipole attractions between molecules caused by a
temporary electron shift
SEB
Answer:
D
Explanation:
Van der Waal forces are small dipole attractions between molecules caused by a temporary electron shift ,here, the option D is correct.
What are Van Der Waal forces?Van der Waals forces exist among all kinds of atoms and molecules. The origin of this force stems from the instantaneous dipole-induced dipole interactions among adjacent polar atoms and molecules.
Among polar molecules, there are three components that contribute to the total forces: the induction force, the orientation force and the dispersion force.
The Van Der Waal forces that act between macroscopic bodies and surfaces in a solvent medium are relevant to the phenomena of protein adsorption.
Van Der Waal forces are the small dipole attractions between molecules caused by a temporary electron shift , thus, option D is correct.
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4. Describe the arrangement of the electrons on each energy level.
Answer:
Explanation:
If the energy of an atom is increased, an electron in the atom gets excited. To go back to its ground state, the electron releases energy. The energy of the light released when an electron drops in energy level is the same as the difference in energy between the two levels.
Viewed simply, electrons are arranged in shells around an atom’s nucleus. Electrons closest to the nucleus will have the lowest energy. Electrons further away from the nucleus will have higher energy. An atom’s electron shell can accommodate 2n2 electrons (where n is the shell level).
In a more realistic model, electrons move in atomic orbitals, or subshells. There are four different orbital shapes: s, p, d, and f. Within each shell, the s subshell is at a lower energy than the p. An orbital diagram is used to determine an atom’s electron configuration.
There are guidelines for determining the electron configuration of an atom. An electron will move to the orbital with lowest energy. Each orbital can hold only one electron pair. Electrons will separate as much as possible within a shell.
In an atom, electrons are arranged in shells that surround the nucleus, with each successive shell moving further away from the nucleus.
What is energy level?In physics, an energy level is any discrete value from a set of total energy values for a subatomic particle confined by a force to a limited space or for a system of such particles, such as an atom or a nucleus.
Energy levels are fixed distances from an atom's nucleus where electrons can be found. Electrons are tiny, negatively charged particles that move around an atom's positive nucleus. The steps of a staircase represent energy levels.
Around the nucleus, electrons are arranged in different shells. Each successive shell can only hold so many electrons. First, the innermost shell is filled. This shell can only contain two electrons.
Thus, this way, the electrons are arranged.
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Can you help me please
what are your steps to this from the lesson
If a wave of red light has a wavelength of 6.7 x 10-7 m, will the frequency of the red wave be high or low?
Answer:
Its high
Explanation:
Becuase if u times it what do u get
(100 POINTS) When thermal energy (heat) is added to a reaction, it happens _________ (faster or slower)
When thermal energy (heat) is removed from a reaction, it happens _________ (faster or slower)
Answer:
1) faster
2) slower
Explanation:
Answer:
faster
Explanation:
Identify whether each element is a halogen, a noble gas, or nonmetal only.
Astatine (At):
Nitrogen (N):
Krypton (Kr):
Chlorine (Cl):
Sulfur (S):
Answer:
Astatine: Halogen
Nitrogen: Non-Metal
Krypton: Non-Metal, Noble Gas
Chlorine: Non-Metal
Sulfur: Non-metal
Explanation:
A dull metal object has a density of 8.8 G/ML and a volume of 20 ML calculate the mass
Answer:
Mass = 0.000176 gram
Steps:
m = V × ρ
= 20 milliliter × 8.8 gram/cubic meter
= 2.0E-5 cubic meter × 8.8 gram/cubic meter
= 0.000176 gram
Explanation:
Write a complete, balanced chemical equation where tin metal reacts with aqueous hydrochloric acid to produce tin(II) chloride and hydrogen gas. Include states.
From the equation, which element is oxidized, and which element is reduced?
Answer:
1. The balanced equation is given below:
Sn (s) + 2HCl (aq) –> SnCl₂ (aq) + H₂ (g)
2a. H is oxidized.
2b. Sn is reduced.
Explanation:
1. Balanced equation for the reaction between tin (Sn) metal and aqueous hydrochloric acid (HCl) to produce tin(II) chloride (SnCl₂) and hydrogen gas (H₂).
This is illustrated below:
Sn (s) + HCl (aq) –> SnCl₂ (aq) + H₂ (g)
There are 2 atoms of Cl on the right side and 1 atom on the left side. It can be balance by putting 2 in front of HCl as shown below:
Sn (s) + 2HCl (aq) –> SnCl₂ (aq) + H₂ (g)
Now, the equation is balanced
2. Determination of the element that is oxidize and reduced.
This can be obtained as follow:
We shall determine the change in oxidation number of each element.
NOTE:
a. The oxidation number of H is always +1 except in hydrides where it is –1.
b. The oxidation state of Cl is always –1.
Sn (s) + 2HCl (aq) –> SnCl₂ (aq) + H₂ (g)
For Tin (Sn):
Sn = 0
SnCl₂ = 0
Sn + 2Cl = 0
Cl = – 1
Sn + 2(–1) = 0
Sn – 2 = 0
Collect like terms
Sn = 0 + 2
Sn = +2
Therefore, the oxidation number of Tin (Sn) changes from 0 to +2
For H:
H = +1
H₂ = 0
The oxidation number of H changes from +1 to 0
For Cl:
Cl is always –1. Therefore no change.
Summary:
Element >>Change in oxidation number
Sn >>>>>>>From 0 to +2
H >>>>>>>>From +1 to 0
Cl >>>>>>>No change
Therefore,
Sn is reduced since its oxidation number increased from 0 to +2.
H is oxidized since it oxidation number reduced from +1 to 0
The balanced chemical equation for the reaction is
Sn(s) + 2HCl(aq) → SnCl₂(aq) + H₂(g)
and the element that oxidized is tin (Sn) while the element that is reduced is hydrogen (H)
The balanced chemical equation for the reaction where tin metal reacts with aqueous hydrochloric acid to produce tin(II) chloride and hydrogen gas is
Sn(s) + 2HCl(aq) → SnCl₂(aq) + H₂(g)
From the equation,
The element that is oxidized is tin (Sn), because the oxidation state of Sn increased from 0 to +2
The element that is reduced is hydrogen (H), because the oxidation state of H decreased from +1 to 0.
Hence,
The balanced chemical equation for the reaction is
Sn(s) + 2HCl(aq) → SnCl₂(aq) + H₂(g)
and the element that oxidized is tin (Sn) while the element that is reduced is hydrogen (H).
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whats the lewis dot diagram for calcium
Draw the Lewis dot structure for each atom of the compound to show how many valence electrons are present in each atom. For example, the calcium atom in calcium chloride, CaCl2, has two valence electrons, and the chlorine atoms have seven valence electrons each.
Which phrase best describes igneous rocks?
form when lava and magma cool
accumulate sediments following erosion
require heat and pressure to be formed
consist of many sediment layers
ctivity
Answer:
A) form when lava and magma cool
please give me brainliest :p
God bless!
Answer:
A: form when lava and magma cools
Explanation:
Got it right on Edge 2020 :)
Identify the mineral that can have the composition of KMg3AlSi3O10(OH)2
Answer:
Phlogopite
Explanation:
It is a member of mica group family of phyllosilicates mineral. It is the magnesium endmember of the biotite stable - the chemical formulation KMg3AlSi3O10 (F, OH) 2.
You check the air pressure in your car tires on Monday morning and the pressure
reads 765 mmHg. A cold front drops the temperature considerably overnight. You
check your tire pressure Tuesday morning and the pressure reads 740 mmHg.
Using what you've learned about the properties of gases, what causes this change
in pressure?
How many moles are in 12.6 grams of K2S?
A
Carpet is beaten to
beaten to remove dust
Answer:
It's Clean?
Explanation:
Determine the amount of energy (heat) in Joules and Kcal required to raise the temperature 0f 98.5 grams water from 37.0 0C to 75.0 0C.
Answer:
15660.712J
Explanation:
Q = m × c × del T
Q(energy) = ?
m (mass) = 98.5g
c = 4.184J
del T = 75-37 = 38 °C
Q = 98.5 × 4.184 × 38
Q = 15660.712 J
when Lithium forms an ionic compound with carbonate, how many of each ion is needed?
Answer:
Two Lithium ions and one carbonate ion
Explanation:
Let us look at this equation;
Li2CO3(s) ------->2Li^(aq) + CO3^2-(aq)
We can see that each unit of Li2CO3 has two lithium ions and one carbonate ion.
Let us not forget that Li has a valency of 1 while carbonate ion has a valency of 2. Exchange of valencies gives the final formula of the compound.
Answer:
Two Lithium ions and one carbonate ion
Explanation:
Which of the following is used for chemical symbols today? a. drawings c. letters b. icons d. numbers
Answer:
Letters
Explanation:
For example, today we use the periodic table which is full of elements named with 1 or 2 letters. Like how Helium is He and Sodium is Na. Hope this helps!!!
Chemical symbols are used to identify an element and it is represented by one or two letters from their latin name. Thus option c is correct.
What is chemical symbol?Chemical symbols are representations for elements and compounds. Each element in the periodic table have their own symbol which first letter or first two letters from their latin name.
For example, hydrogen has the symbol H, oxygen is O, N for nitrogen C for carbon, Na for sodium etc. The latin name of sodium is natrium, that's why it has the symbol Na.
The letters used in the chemical symbol must be capital. If two letters are there like in Na, Ar etc. the first letter be capital and second letter have to be in small case.
In a similar way compounds can be represented using chemical symbols with number of each atom given as subscripts of the elemental symbol as in CO₂, H₂O etc.
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Who still uppppppp and boreddddd
Answer:
me
Explanation:
The quantum mechanical model...
a
describes electrons as moving through specific circular orbits, and not staying in one place.
b
places electrons in fixed positions, not moving through specific orbits or orbitals.
c
describes electrons as moving anywhere in the atom, not specific circular orbits.
d
describes electrons as moving through cloud-like orbitals, not specific circular orbits.
Two people are pulling on a rope, like in the picture below. The person on the left pulls at 5 N and the person on the right pulls 5 N. What is the net force on the rope?
Answer:
The net force is 0
Explanation:
because both people on either side are pulling the rope with the same force
during recycling, ground glass is melted under light heat and poured into molds. which type of change occurs as the glass melts?
The state change occurs when the glass melts.
What are different states of matter?The matter is anything that has mass and occupies space.
The different states of matter are solid, liquid, gas, and plasma.
The properties of the different types of matter can be understood by looking at the arrangement of molecules.
When a solid substance is heated beyond its melting point, it changes its state from solid to liquid.
When liquid is heated beyond its vaporizing point, it changes its state from liquid to gas.
Solids are closely packed and have a definite shape and size.
Liquids are loosely packed and take up the space of the container.
Gas has high intermolecular spacing and the gases are not rigid.
Ground glass is melted under light heat and poured into molds.
Recycling glass involves changing the state of glass from solid to liquid state.
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How would an astronomer identify our home in the universe? Earth is in the solar system. The Milky Way is in the solar system. The solar system is next to the Milky Way. Earth is in the Milky Way and next to the solar system. The Milky Way is in the universe. The solar system is in the Milky Way. Earth is in the solar system. The universe is in the Milky Way. The Earth is in the Milky Way. Earth is at the center of the solar system.
Answer:
Earth is in the solar system.
Explanation:
Earth is our home and it is in the solar system.
Earth is the fifth-largest of the planets in the solar system and the third planet from the sun. Earth is the only planet having oxygen and water that supports life. Till now according to the research Earth is the only planet having life.
Planets are in the solar system, the solar system is in the milky way and the milky way is present in the universe. The astronomer identifies our home in the universe as "Earth is in the solar system" as Earth is our home.
Hence, the correct answer is "Earth is in the solar system."
Answer:
The Milky Way is in the universe. The solar system is in the Milky Way. Earth is in the solar system.
Explanation:
If the Milky Way Is in the universe and solar system you would know earth is also In the solar system, so "Our home planet is the third planet from the Sun, and the only place we know of so far that's inhabited by living things. While Earth is only the fifth largest planet in the solar system, it is the only world in our solar system with liquid water on the surface."