Answer:
Mass percent of silicon = 46.75% (Approx)
Explanation:
Given:
Mass of silicon = 0.389 g
Mass of silicon dioxide = 0.832 g
Find:
Mass percent of silicon
Computation:
Mass percent of silicon = Mass of silicon / Mass of silicon dioxide
Mass percent of silicon = [0.389 g / 0.832 g]100
Mass percent of silicon = 46.75% (Approx)
Not sure what to do here. It says to convert the following into formulas and states in an unbalanced equation. Please help!
Answer:
Ca2 solid state
H2O liquid state
Ca(OH)2 I believe this would be in solid state
H2 gas state
Explanation:
What is the name of the 3 lenses that have different powers of magnification 4x, 10x and 40x
Answer:
Scanning Objective Lens (4x)
Low Power Objective (10x)
High Power Objective Lens (40x)
Explanation:
Which part of an atom is gained, lost, or shared during a chemical reaction? (2 points)
оа
Electron
Oь
Proton
ос
Neutron
Od
Nucleus
Answer:
a) electron
Explanation:
Answer:
a
Explanation:
i took the test
Ice melting to become water is an example of a physical change.
True or false
Answer:
true
Explanation:
After ice melts into liquid water, you can refreeze it into solid ice if the temperature drops. Freezing and melting are physical changes. The substances produced during chemical changes however cannot easily change back into the original substances.
The molecule NHz contains all single bonds. False or true?
Answer:
true
Explanation:
Which of the following can be predicted using the activity series?
Speed of an acid-base reaction
Speed of a double replacement reaction
Possibility of a double replacement reaction
Possibility of a single replacement reaction
Answer:
Possibility of a single replacement reaction
Explanation:
The activity series of element can be used to predict the possibility of a single replacement reaction.
A single replacement reaction is one in which one substance is replacing the other. The replacement of a metallic ion in solution by a metal atom higher in the activity series than the metal in solution falls into this category of reactions. The relative position of the two elements in the activity series provides the driving force for this kind of reaction. If the element to replace the other is more reactive, the reaction will occur. If it is less reactive, the reaction will not occur.Answer:
Possibility of a single replacement reaction
Explanation:
what characteristics are shared by elements in the same period row?
Answer:
Elements in the same period have the same number of electron shells.
Explanation:
elements gain electrons and protons and become less metallic
#45 State whether the following sets of quantum numbers are valid. If the set of quantum numbers aren’t valid, indicate why.Indicate what orbital the electron is in regardless of whether the numbers are valid or not.
n = 3 l = 3 ml= 0 ms= +1/2
n = 2 l = 1 ml= -1 ms= -1/2
n = 3l = 0 ml= 1 ms= +1/2
#46 Give the “COMPLETE” electron configuration for antimony. Is it paramagnetic or diamagnetic? If there are unpaired electrons, indicate how many.
Answer:
(a) "l" cant be more than n-1. n= 3 so l cant be more than 2.
(b) Valid
(c) If l=0, ml can only be 0.
Sb, Antimony, 51 electrons
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p3
paramagnetic 3 unpaired electrons
Explanation:
(a) "l" (lower case L) can be 0, 1, 2 up to n-1. If n=3, l can be 0, 1, or 2.
(b) This set of quantum numbers is valid. n can be 1, 2, 3, ...
since n= 2, l can be any number from 0 to n-1 or 0,1
Since l=1, ml can be -1, 0, 1
ms can always be +1/2 or -1/2
(c) ml can only be from -l to +l. If l=0, ml=0.
If l was 2, ml could be -2, -1, 0, 1, 2
The distance from San Francisco to Los Angeles is approximately 385 miles. 1609 m = 1 mile. How many kilometers is this? Do not enter “kilometers” as part of your answer.
Answer:
619.465 kilometers
Explanation:
1609 m = 1 mile
so 385 miles is equal to 619465 meters (385 x 1609= 619465)
1000 meters = 1 km
so 619465 meters is 619.465 kilometers
A balloon is floating around outside your window. The temperature outside is 39 °C, and the air pressure is 0.800 atm.
Your neighbor, who released the balloon, tells you that he filled it with 4.70 moles of gas. What is the volume of gas inside
this balloon?
Express your answer numerically in liters.
Answer:
V = 150.49 L
Explanation:
Given data:
Pressure = 0.800 atm
Temperature = 39 °C (39+273 = 312 K)
Moles of gas = 4.70 mol
Volume of gas = ?
Solution:
Formula:
PV = nRT
V = nRT/P
V = 4.70 mol × 0.0821 atm.L/mol.K × 312 K / 0.800 atm
V = 120.39 atm.L/ / 0.800 atm
V = 150.49 L
Sodium, potassium, and cesium belong to which group?
inner transition metals
halogens
alkali metals
Answer:
Alkali Metals
Explanation:
A student who is feeling cold rapidly rubs their hands on their bare arms. What energy transformation is the student using to feel warmer?
A.
mechanical ---> thermal
B.
radiant ---> thermal
C.
thermal ---> chemical
D.
electrical ---> thermal
Answer:
B
Explanation:
Answer:
B.
radiant ---> thermal
Explanation:
(2 points) How many grams of K2SO4 are present in 25.0 mL of 7.00 % (m/v) solution?
Show your work. No work = no credit.
Mass of K₂SO₄ : 1.75 g
Further explanationThe concentration of a substance can be expressed in several quantities such as moles, percent (%) weight/volume,), molarity, molality, parts per million (ppm) or mole fraction. The concentration shows the amount of solute in a unit of the amount of solvent.
volume of solution = 25 ml
% (m/v)=7%
mass of K₂SO₄ :
[tex]\tt \%m/v=\dfrac{mass~of~solute}{volume~of~solution}\times 100\%\\\\7\%=\dfrac{mass~K_SO_4}{25}\times 100\%\\\\mass~K_2SO_4=7\times 25\div 100=1.75~g[/tex]
Starch and glycogen
are both polysacharides.
True or false
Based on the information above, which statement provides evidence that a chemical reaction has occurred?
Products release more energy than reactants
Reactants form from the atoms that make up products
There are more atoms in the products than in the reactants
Atoms that make up reactants rearrange into new products
Answer: Atoms that make up reactants rearrange into new products
Explanation:
A chemical reaction is the process of breaking down the chemical bonds of the reacting substances which are commonly called as reactants and making new bonds to form new substances commonly called as products.
The products will contain the same atoms as there are in the reactants but the bonds will rearrange to form different substances.
Every chemical reaction is accompanied with absorption or release of energy.
A solution of potassium sulfide is mixed with a solution of magnesium bromide. Identify the two possible products.
Answer:
Magnesium sulfide and potassium bromide.
Explanation:
Hello!
In this case, for the two mentioned solutions, which are composed by both potassium sulfide (K2S) and magnesium bromide (MgBr2), the following chemical reaction would be carried out:
[tex]K_2S+MgBr_2\rightarrow MgS+KBr[/tex]
However, due to the discrepancy in the atoms of bromine and potassium, the balanced chemical equation should be:
[tex]K_2S+MgBr_2\rightarrow MgS+2KBr[/tex]
Whereas the products are magnesium sulfide and potassium bromide which are both soluble in water.
Best regards!
How many outer-shell d electrons are there in each of the transition-metal ions?Mn(IV) :Co(III) :Fe(II) :Ni(II) :
Answer:
Mn(IV): 3 outer-shell d electrons
Co(III): 6 outer-shell d electrons
Fe(II): 6 outer-shell d electrons
Ni(II): 8 outer-shell d electrons
Explanation:
Mn(IV):
The ion is Mn⁴⁺, so it has lost 4 valence electrons. The ground state electronic configuration of Mn is [Ar]3d ⁵ 4s ². When the neutral atom loses 4 electrons, the electronic configuration is [Ar]3d ³.
outer-shell d electrons = 3
Co(III):
The ion is Co³⁺, so it has lost 3 valence electrons. The ground state electronic configuration of Co is [Ar]3d ⁷4s ². When the neutral atom loses 3 electrons, the electronic configuration is [Ar]3d ⁶.
outer-shell d electrons = 6
Fe(II):
The ion is Fe²⁺, so it has lost 2 valence electrons. The ground state electronic configuration of Fe is [Ar]3d ⁶4s ². When the neutral atom loses 2 electrons, the electronic configuration is [Ar]3d ⁶.
outer-shell d electrons = 6
Ni(II):
The ion is Ni²⁺, so it has lost 2 valence electrons. The ground state electronic configuration of Ni is [Ar]3d ⁸4s ². When the neutral atom loses 2 electrons, the electronic configuration is [Ar]3d ⁸.
outer-shell d electrons = 8
The d electron in the outer shell of each of the transition metal are:
Mn(IV): 3 d electrons in the outer shell.
Co(III): 6 d electrons.
Fe(II): 6 d electrons.
Ni(II): 8 d electrons.
What is electronic configuration?Electronic configuration is the arrangement of the electrons of an atom.
There are subshell s, p, d, f.
The electrons are arranged in these subshells.
Each element has different arrangement of electrons.
Thus, the number of d electron in each of the element is: Mn(IV) :3, Co(III) :6, Fe(II) :6, Ni(II) :8.
Learn more about electronic configuration
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What state of matter is hydrogen?
Answer:
its a gas
Explanation:
Hydrogen is the chemical element in the periodic table that has the symbol H and atomic number 1. At standard temperature and pressure it is a colorless, odorless, non-metallic, univalent, highly flammable diatomic gas. Hydrogen is the lightest and most abundant element in the universe.
In the given question, the state of matter of Hydrogen is gas in nature.
A state of matter is one of the four distinct forms in which matter can exist as solid, liquid, gas, and plasma.
Hydrogen is a chemical element that occurs naturally as a gas at standard temperature and pressure (STP). It is the lightest and most abundant element in the universe and is found in stars, gas giants, and other celestial bodies.
It is also used in various industrial processes, such as the production of ammonia and methanol, and as a fuel source in fuel cells.
Therefore, hydrogen is in the gaseous state at room temperature and normal atmospheric pressure.
Learn more about State of matter here:
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Calculate the number of moles of Cl atoms in 1.81×1024 formula units of magnesium chloride, MgCl2.
The highpoint of a wave is called a
Answer:
crest
Explanation:
why the Modern dry process is preferred to another conventional process?
12. Calculate the no of molecules in:
34g of ammonia molecules, NH3
Answer:
1.2 × 10²⁴ molecules NH₃
General Formulas and Concepts:
Chemistry
Reading a Periodic TableAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Dimensional AnalysisExplanation:
Step 1: Define
34 grams NH₃
Step 2: Define conversions
Avogadro's Number
Molar Mass of N - 14.01 g/mol
Molar Mass of H - 1.01 g/mol
Molar Mass of NH₃ - 14.01 + 3(1.01) = 17.04 g/mol
Step 3: Convert
[tex]34 \ g \ NH_3(\frac{1 \ mol \ NH_3}{17.04 \ g \ NH_3} )(\frac{6.022 \cdot 10^{23} \ molecules \ NH_3}{1 \ mol \ NH_3} )[/tex] = 1.20157 × 10²⁴ molecules NH₃
Step 4: Check
We are given 2 sig figs. Follow sig fig rules.
1.20157 × 10²⁴ molecules NH₃ ≈ 1.2 × 10²⁴ molecules NH₃
A image of a drag race car has long arrow A pointing up, medium length arrow B pointing down, medium length arrow C pointing forward and left, and short arrow D pointing backward and right. Which arrow represents the force of gravity acting upon the car? Which arrow represents the normal force on the car? Which arrow represents the applied force on the car when the driver steps on the gas pedal?
Which arrow represents the force of gravity acting upon the car?
✔ B
Which arrow represents the normal force on the car?
✔ A
Which arrow represents the applied force on the car when the driver steps on the gas pedal?
✔ C
10 m/s to 80 m/s in 5 seconds
900 mph................
Answer:
a = 0.8 m/s/s
Vav = 45m/s
Explanation:
Vav = [tex]\frac{Vi + Vf}{2\\}[/tex]
Vav = [tex]\frac{10 +80}{2}[/tex]
Vav = 45m/s
a = [tex]\frac{v}{t}[/tex]
a = [tex]\frac{4m/s}{5s}[/tex]
a= 0.8m/s/s
1s22s22p63823p64523d104p5s24d105p5
What is the name of the element?
Answer:
IODINE
Explanation:
The sublevel notation of the element:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹⁰ 5p⁵
To find this element, we must add the powers of the each of the sublevels. This is the number of electrons in the orbital of the atom.
2 + 2 + 6 + 2 + 6 + 2 + 10 + 6 + 2 + 10 + 5 = 53
This give atom has 53 electrons and we can assume it to have an atomic number of 53.
The element is IODINE
Which statement is true about S-waves?
A They are the slowest selsmic waves.
B They travel only through solids.
They are the first to be detected by
seismometers.
D They can travel through solids and
liquids.
please help
Answer:
B They travel only through solids.
Explanation:
Seismic s-waves are also known as secondary or shear-waves. They are elastic waves that travels within a body.
At a seismic station, they are the second set of waves to arrive after the primary - waves. They can only pass through solid bodies as fluids cannot be sheared. The above mentioned property makes them very useful in determining the interior property of the earth. They are not the slowest seismic waves.A nitrogen atom in N, should have a
charge of 1-
partial charge 6+.
charge of 0.
partial charge
What is the total number of electrons in a S2- jon?
1.
10
2.
14
16
4.
18
the answer is D) 18 electrons
A student determines that the number of moles in a sample of Al2O3 is 8.3 moles. How many grams are in the sample?
Mass : 846.268 g
Further explanationThe mole is the number of particles contained in a substance
1 mol = 6.02.10²³
Moles can also be determined from the amount of substance mass and its molar mass
[tex]\tt mol=\dfrac{mass}{MW}[/tex]
mass of Al₂O₃ :
MW 101,96 g/mol
mass=mole x MW
[tex]\tt 8.3\times 101.96=846.268~g[/tex]
how to find the number of neutrons
Answer:
For all uncharged atoms, the number of electrons equals the number of protons. The mass number 40 is the sum of protons and neutrons. To find the number of neutrons, subtract the number of protons from the mass number.
Answer:
mass number- protons
Explanation: