Answer:
Oceanic crust is not only thinner and denser than continental crust, and it is also much younger than it and has a different chemical composition. When magma from the mantle of the earth finds a way up, it comes into contact with water that cools it down quickly
easons for the dense packing in metals
Explanation:
Typically, only one element is present, so all atomic radii are the same. -Metallic bonding is not directional. -Nearest neighbor distances tend to be small in order to lower bond energy.
why is the cell wall so important to the plant cell???
Explanation:
Cellulose fibers, structural proteins, and other polysaccharides help to maintain the shape and form of the cell. Additional functions of the cell wall include: Support: The cell wall provides mechanical strength and support. It also controls the direction of cell growth.
What is the empirical formula for a compound that has 57.5%
Na, 40.0% 0, and 2.5% H?
a
Naz(OH)4
b
Na(OH)2
С
Na(OH)
d
Naz(OH)
Answer:
c
Explanation:
use %composition given to calculate emperical 4mular
The empirical formula of the compound having 57.5% Na, 40.0% O, and 2.5% H is NaOH (Option C)
Data obtained from the questionNa = 57.5%O = 40%H = 2.5%Empirical formula =?How to determine the empirical formulaDivide by their molar mass
Na = 57.5 / 23 = 2.5
O = 40 / 16 = 2.5
H = 2.5 / 1 = 2.6
Divide by the smallest
Na = 2.5 / 2.5 = 1
O = 2.5 / 2.5 = 1
H = 2.5 / 2.5 = 1
Thus, the empirical formula of the compound is NaOH
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If 45.0 mL of ethanol (density =0.789g/mol) initially at 6.0°C mix with 45.0 mL of water (density =1.0 g/mol) initially at 28.0°C in an insulated beaker, what is the final temperature of the mixture, assuming that no heat is lost? (CetOH =2.42 J/G C)
The final temperature of the mixture : 21.1° 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 in(gained) = Q out(lost)
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
Q ethanol=Q water
mass ethanol=
[tex]\tt mass=\rho\times V\\\\mass=0.789\times 45=35.505~g[/tex]
mass water =
[tex]\tt mass=1~g/ml\times 45~ml=45~g[/tex]
then the heat transfer :
[tex]\tt 35.505\times 2.42~J/g^oC\times (t-6)=45\times 4.18~J/g^oC\times (28-t)\\\\85.922t-515.533=5266.8-188.1t\\\\274.022t=5782.33\rightarrow t=21.1^oC[/tex]
What is the mass number of an atom that consists of 20 protons, 20 neutrons, and 18 electrons?
Answer:
C)a mass number of 38
Explanation:
yes
Newton's Second Law of Motion says that the acceleration of an object depends on the object's mass and the
A
equation E=MC^2E=MC
2
.
B
amount of force applied to the object.
C
negative acceleration factor.
D
amount of atoms the object has.
Answer: Hello! I do believe the answer is A.
Explanation: please mark me brainliest! hope this helps
Answer:
B
Explanation:
A 1599 kg car is traveling down the road at 83.4 km/h. While traveling at this rate of speed, what is the kinetic energy of this vehicle in kilojoules?
Ek=
A 56.87 g sample of a substance is initially at 30.0 °C. After absorbing 1475 J of heat, the temperature of the substance is 138.4 °C. What is the specific heat ( ) of the substance?
c=
The kinetic energy of 429 kJ and the specific heat of the substance is 9059 g kJ °C
The kinetic energy is given as ,
K.E = 1/2 m[tex]v^{2}[/tex]
Where m = mass = 1599 kg
v = velocity = 83.4 km/h = 23 m/s
Putting the value mass and velocity in equation ( i ) we get ,
K.E = 1/2 × 1599 kg × 23 m/s × 23 m/s = 429074.86 J = 429 kJ
Specific heat is calculated as ,
Q = mcΔT
mass of the substance ( m ) = 56.87 g
c = 1475 J
ΔT = 138.4 °C - 30.0 °C = 108 °C.
Putting the value of mass , change in temperature and heat absorbed in equation ( ii ) we get ,
Q = 56.87 g × 1475 J × 108 °C = 9059391 gJ°C = 9059 g kJ °C
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List 3 properties of the hair’s cuticle.
Two gases, helium and X, are released from one end of an evacuated long cylinder at the same time. If it takes the helium atoms 3 times faster than gas X to effuse from one end of the cylinder to the other end, what is gas X?
Answer:
The correct answer is HOF gas.
Explanation:
Based on the given information, the helium atoms effuses three times faster in comparison to the gas X.
The rate of effusion is determined by,
r is inversely proportional to 1/√M, here M is the molecular mass of the gas.
and r is inversely proportional to 1/t, here t is the time taken for effusion.
Thus, t is directly proportional to √M
The molecular mass of He is 4.
tHe = tX/3 (Here tx is the time taken for gas X)
The molecular mass of X is not known.
tX/tHe =√Mx/MHe
3 = √Mx/4
By squaring both the sides we get,
9 = Mx/4
Mx = 36
36 is the molecular mass of gas HOF, that is, (1+16+19 = 36). Hence, the gas X is 36.
This table shows data collected about four different landforms. Landform What Is Its Landmass? What Is Its Shape? Is There Water? W Large Has steep sides No X Large Goes down and comes back up No Y Small A circle Filled with water Z Small Rises up in the middle then goes back down Surrounded by water Question Which landform is an island?
A.
W because it has steep sides.
B.
X because it dips in the middle.
C.
Y because it is small and a circle.
D.
Z because it is surrounded by water
Answer:
answer is d
Explanation:
because it is surrounded by water
How do we write a formula for those combinations of atoms?
Answer:
please follow me
Explanation:
hope it helps.......
Can someone please help me with this
Ques. A uniform cylinder of mass 4.3 kg and radius 0.4 m rolls down a ramp inclined at an angle 0.15 radians to the horizontal. What is the acceleration of the cylinder in m/s2 ?
The acceleration of the cylinder in m/s2 is 0.973 meters per seconds squared.
What is acceleration?Acceleration is the change of velocity with time. The unit is usually meters per seconds squared.
mass = 4.3 kg
radius = 0.4m
angle of inclination, ∅ = 0.15 radians
How to solve acceleration of the cylinder in m/s^2acceleration of the cylinder in m/s^2
= ( g + sin ∅ ) / 1 + 0.5
= ( 9.81 + sin 0.15 ) / 1.5
take note angle is in radians not degrees
= 1.46 / 1.5
= 0.973 meters per seconds squared
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13. When pentane undergoes complete combustion, the products are carbon dioxide and water.
C5H12
+ 02 →
CO2 +
H20
What are the respective coefficients when the equation is balanced with the smallest whole numbers?
a. 1,5, 3, 4
b. 2, 6, 5, 6
c. 1, 8, 5,6
d. 2, 16, 10, 12
Answer:
i think c
Explanation:
:D
Calcium carbonate is a white mineral. A chemist heats calcium carbonate, CaCO3, to produce carbon dioxide, CO2, and a white powder, CaO. The following chemical equation shows the reaction.CaCO3 → CO2 + CaO Explain why the products have different properties than the reactants
Answer:
A chemical change has occurred
Explanation:
Given reaction expression:
CaCO₃ → CaO + CO₂
The reaction is a decomposition reaction in which a compound is dissociated into simple products.
The reason why the products have different properties than the reactants is because a chemical change has occurred.
A chemical change is accompanied by the formation of a new productSuch new products have different properties compared to the compound that forms them. Therefore, the products and reactants are different chemically due to chemical change that has occurred.The products of the decomposition of calcium carbonate have different properties because a chemical change has occured in the reaction to form new substances.
CHEMICAL CHANGE:A chemical change is a type of change in which new products are formed. The bonds of the reactants are broken and rearranged to form entirely new substances. According to this question, calcium carbonate is a white mineral, which when heated produces carbon dioxide, CO2, and a white powder, CaO as follows: CaCO3 → CO2 + CaOThe products in this reaction are different in their properties from the reactants because a chemical change has caused new substances to be formed.Learn more about chemical change at: https://brainly.com/question/1161517?referrer=searchResults
if T1=454 K and T2=356 K atm and V1=101.85 mL. then what is V2? please help asap!!!
Answer:
opp
Explanation:
If the pH of a certain solution changes from 8 to 9, what happens to the hydrogen ion concentration
The concentration of OH⁻ ions will become 10 times the initial concentration.
What is indicated by the hydrogen ion concentration?A more useful approach to express the concentration of hydrogen ions is on the pH scale, which is the logarithm of the reciprocal of the hydrogen ion concentration in gram moles per liter. The concentrations of the hydrogen ion (H+) and the hydroxyl ion (OH) are both equal to 10⁻⁷ in a neutral solution. The pH of seven is neutral.
Solution pH 1 equals 8.
Solution's pH is 2 = 9.
pOH₁ = 14 - 8 = 6
pOH₂ = 14 - 9 = 5
OH₁⁻ = 10⁻⁶
OH₂⁻ = 10⁻⁵
Ratio = 10⁻⁵ / 10⁻⁶ = 10
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Pb in tetraethyl lead, Pb(C2H5)4 (once extensively used as an additive to gasoline to prevent engine knocking)
Express your answer using four significant figures. Determine the percent,by mass, for Pb
The percent mass of lead in tetraethyl lead is 64.1%.
What is the percent by mass of Pb in tetraethyl lead, Pb(C₂H₅)₄?The percent by mass of an element in a compound is determined by taking the ratio of the atomic mass of the element and the molar mass of the compound and then multiply by 100%
Percent mass = (atomic mass of element/molar mass of compound) * 100%atomic mass of Pb = 207
atomic mass of C = 12
atomic mass of H = 1
Molar mass of tetraethyl lead: 207 + 12 * 2 * 4 + 1 * 5 * 4
Molar mass of tetraethyl lead = 323 g/mol
Percent mass of Pb = 207/323 × 100%
Percent mass of Pb = 0.6408 × 100%
Percent mass of Pb = 64.1%
In conclusion, the percent mass of lead in tetraethyl lead is 64.1%.
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What is the mass of 3.99 mol of nickel?
Answer:
234.213
Explanation:
Moles of Nickel x 58.70 = Grams
3.99 x 58.70 = 234.213
which statement best describes what happens during mitosis
Answer:
Osmosis is a process which occurs when there is a difference in solute concentration between two solutions separated by a semipermeable membrane. A semipermeable membrane allows passage of water but not of solutes. The passage of water occurs because of a pressure difference of water between the two solutions
wich of the following solute and solventis not belong to suspension mixture
A.sticky, creamy subtances
B.clear, pure subtances
C.dark, black subtances
D.clear, flowless sunbtances
b is your best bet hope this helps
If an electron falls from the n = 2 to the n = 1 energy levels in a Hydrogen atom what wavelength of light is emitted?
Answer:
Ultraviolet
Explanation:
It doesn't use much energy and so it creates ultraviolet light.
The term "cycle" is used in Water Cycle because ?
Answer:
because cycle is a prosess that goes through multiple stages
Explanation:
.
A person has a mass of 63.4kg. What is the weight in pounds?
Please help me I need these answers
Answer:
Q8) True
Q9) First ionization energy
Q10) A metal oxide
Explanation:
One of the properties of group one elements (alkali metals) is that they combine with water to form basic solutions. E.g 2Na(s)+2H2O(l)→2NaOH(aq)+H2(g).
An inverse relationship exists between the distance of the outermost electron in the atom from the nucleus and the first ionization energy. As the distance between the outermost electron and the nucleus in group 17 elements increases, their first ionization energies decreases accordingly.
Group 1 elements react with oxygen to yield the corresponding metal oxides. E.g 4 Na + O2 --> 2 Na2O
If the loss of 3500 kcal is equal to a loss of 1.0 lb, how many does will it take Charles to loose 5.0 lb
which subatomic particle made out of protons neutrons and electrons can charge and still be considered the same element
Answer:
Proton
Explanation:
The density of silver is 10.5 g/cm³. A students performs three trials of an experiment and obtains the
following results: 14.2 g/cm³, 14.0 g/cm³, and 7.25 g/cm³. Are these results accurate? Explain. Are the
results precise? Explain.
Results are neither precised nor accurate.
In the Given Actual density of silver =10.5 g / cm^3
Measured values of silver density = 14.2 g/cm^3
14.0g/cm^3
7.25g/cm^3
We have to find whether the measurements given are accurate or precise.
so , Density can be defined as the ratio of mass to volume. The formula for calculation of density is shown below :
Density = Mass / Volume
The units of density is generally g / ml.
The results are said to be accurate if our measured value exactly matches with our true value.
In case of precision ,all the measured values should be near to each other or should differ only by 0.1 or 0.2.
So in this case the measured values are not precised nor accurate because it does not matches with true value also.
Hence , the results are neither precised nor accurate.
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Make the following conversion.
954 g= _ kg
0954000
95400
0.954
0.0954
Answer:
0.954
Explanation:
1000 grams is 1 kg
954 grams is 954/1000 kg or 0.954
1. Why the names such as sodium(l) chloride for NaCl and
magnesium(II) chloride for MgCl2 are not used?
Answer:
It's because the NaCl and MgCl2 is shorter and easier to remember