Answer:
D. They are usually liquids or gases at room temperature.
Explanation:
Covalent compounds have covalent bonds, meaning that they share electrons between elements and have relatively higher melting melting and boiling points due to the strength of their bonds. However covalent bonds are weaker than ionic bonds which is why B is correct. D is the only incorrect one because it is incorrect and contradicts point C. If a substance has a high melting/boiling point than it is much more likely to be solid at room temperature because of the high temperature it needs to pass in order to be a liquid or gas.
Hope this helped!
A community includes
A. all of the living organisms in a specific place at a specific time,
B. all plants, animals, minerals, and water in a specific place at a specific time,
C. only the plants in a specific place at a specific time.
D. only the animals in a specific place at a specific time.
Answer:
answer: A. all of the living organisms in a specific place at a specific time
Explanation:
What is the mole fraction of Ba(OH)2 in an aqueous solution that contains 22.8% Ba(OH)2 by mass?
Answer:
0.03
Explanation:
22.8 g Ba(OH)2 (1 mol Ba (OH)2/ 171.34 g) = 0.133 mol Ba (OH)2
77.2 g H2O (1 mol H2O/18 g) = 4.29 mol H2O
X= molar fraction= mol Ba(OH)2/ mol total
X= 0.133/ (0.133+4.29) = 0.03
0.03 is the mole fraction of [tex]Ba(OH)_2[/tex] in an aqueous solution that contains 22.8% [tex]Ba(OH)_2[/tex] by mass.
What is a mole fraction?The ratio of the number of moles of one component of a solution or other mixture to the total number of moles representing all of the components.
Moles of [tex]Ba(OH)_2[/tex]
Moles = [tex]\frac{mass}{molar \;mass}[/tex]
Moles = [tex]\frac{22.8 g Ba(OH)_2}{171.34 g}[/tex]
= 0.133 mol [tex]Ba (OH)_2[/tex]
Moles of [tex]H_2O[/tex]
[tex]Moles = \frac{mass}{molar \;mass}[/tex]
[tex]Moles = \frac{77.2 g H_2O}{18 g}[/tex]
= 4.29 mol [tex]H_2O[/tex]
The mole fraction of [tex]Ba(OH)_2[/tex]
[tex]\frac{mol Ba(OH)_2}{total \;mol}[/tex]
= 0.03
0.03 is the mole fraction of [tex]Ba(OH)_2[/tex] in an aqueous solution that contains 22.8% [tex]Ba(OH)_2[/tex] by mass.
Learn more about the mole fraction here:
https://brainly.com/question/8076655
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how does the sun light affect earths climate
Answer:
The Sun powers life on Earth; it helps keep the planet warm enough for us to survive. It also influences Earth’s climate: We know subtle changes in Earth’s orbit around the Sun are responsible for the comings and goings of the past ice ages. But the warming we’ve seen over the last few decades is too rapid to be linked to changes in Earth’s orbit, and too large to be caused by solar activity
Explanation:
How many electrons with chlorine (Cl) in group 17 gain to become stable?
Answer:
Sodium is in group 1 so it has 1 valence electron (one electron in its outer shell). Sodium will be looking to lose its one valence electron in order to become more stable. Chlorine is in group 17 so it has 7 valence electrons, and therefore only needs to gain one valence electron to attain noble gas electron configuration (become stable with 8 valence electrons, just like the noble gases in group 18 have 8). Because the chlorine atom is trying to gain one electron, and the sodium atom is trying to lose one, sodium will give up its one valence electron to chlorine and the two atoms will form an ionic bond. Because chlorine is looking to gain just one electron and sodium is looking to lose the same number, the ratio of chlorine atoms to sodium atoms will be 1:1, one chlorine atom per one sodium atom.
Explanation:
how many moles of solute are present in 50.0 ml of 0.20 m kno3
Answer: Volume = 50.0 mL in liters : 50.0 / 1000 = 0.05 L
n = M x V
n = 0.20 x 0.05
n = 0.01 moles of solute
Explanation:
The number of moles of solute are present in 50.0 mL of 0.20 M of KNO₃ solution is 0.01 moles.
How do we calculate moles?Moles will be calculated by using the molarity formula because molarity is define as the no. of moles of solute present in per liter of the solution as:
M = n/V, where
M = molarity of KNO₃ = 0.2 M
V = volume of solution = 50mL = 0.05L
Moles will be calculated as:
n = (0.2)(0.05) = 0.01 moles
Hence required moles are 0.01 moles.
To know more about molarity, visit the below link:
https://brainly.com/question/26528084
Need help with these three pls!!!!!
Relate dark matter to the development of the universe after the Big Bang. In 3-5 sentences, speculate on how the development of the universe would have been different if there had been no dark matter. In your answer, use the term structures.
Please answer this and ill mark you as brainliest
Answer:
Dark matter also called baronic matter is the matter that makes up 27% of the universe.
In 1933 it was determined as that mass that cannot be seen, that is, the non-visible mass of outer space.
Dark matter also plays a central role in the formation of structures and the evolution of galaxies and has measurable effects on the anisotropy of cosmic microwave background radiation. The composition of this matter is unknown today.
The dark matter component has considerably more mass than the "visible" component of the Universe.
Explanation:
There are certain researchers who say that the appearance of dark matter was before the appearance of the big bang.
A relevant fact of this matter is that dark matter exerts gravity, and that gravity affects the movements of objects.
Despite the fact that nothing is known about its origin, astronomers have amply demonstrated that dark matter plays a determining role in the formation of galaxies and galactic clusters, which could not maintain their cohesion without its existence, but many doubt that it is the remainder / remnant or product of a big bang.
After brushing, Fluffy's fur has a charge of +8.0 x 10' coulombs and her plastic brush has a charge of -1.4 x 10-8 coulombs. If the distance between the fur and
brush is roughly 5.0 * 10 meters, what is the approximate magnitude of the force between them?
(k = 9.0 * 10 newtonmeters/coulomb?)
A 5.0 x 106 newtons
B.
2.0 x 10-4 newtons
C
4.0 x 106 newtons
D. 2.5 x 10 newtons
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SUS
Answer:
jeez thats some calculus stuff right there im pretty sure its b
Explanation:
What is the correct answer? Please
Answer:
c
Explanation:
What kind of energy transformations occur when you hit a coconut with a hammer
sound energy, kinetic energy,
i cant think of any more but hope this helps
Answer:
Mechanical to kinetic to sound to heat
Explanation:
Remember that all types of energy transformation end in heat
Which substance should a student apply to the skin if he or she gets splashed with an acid?
At 25ºC, the average velocity of a hydrogen molecule is 1.92 x 103 m/s. What is the average velocity of a nitrogen molecule at the same temperature?
NEED WORK
Answer:
V = 513.36m/s
Explanation:
Temperature (T) = 25°C = (25 + 273.15) = 298.15K
Speed (V) = 1.92*10³m/s
According to kinetic theory of gases, the speed (v) of a molecule is
V= √(3RT / M)
V = speed or velocity
R = ideal gas constant = 0.082J/mol.K
T = temperature of the gas
M = molar mass
Molar mass of hydrogen molecule = 2.0g/mol
Molar mass of Nitrogen molecule = (2×14.0) = 28.0g/mol
Since they're in the same temperature
V1 / V2 = √(M2 / M1)
1.92×10³ / V2 = √(28 / 2)
1.92×10³ / V2 = √(14)
1.92*10³ / V2 = 3.74
1.92*10³ = 3.74V2
V2 = 1920 / 3.74
V2 = 513.36m/s
The velocity of Nitrogen molecule is 513.36m/s
what happens to the density of a box full of leaves if you crush up all the leaves and place them in another box
A the density increases
B the density stays the same
C the density decreases
D the density first decreases, then increases
Answer:
B the density stays the same
1. Which gas will move faster through a small opening hydrogen or oxygen? *
A)hydrogen
B) oxygen
Answer:
hydrogen
Explanation:
(7.02 LC) Which statement about this reaction is correct?
Answer: The reaction of one mole of oxygen [tex](O_2)[/tex] releases 445 kJ of energy.
Explanation:
Exothermic reactions are defined as the reactions in which energy of the product is lesser than the energy of the reactants. The total energy is released in the form of heat and [tex]\Delta H[/tex] for the reaction comes out to be negative.
Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and [tex]\Delta H[/tex] for the reaction comes out to be positive.
[tex]CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(l)[/tex] [tex]\Delta H=-890kJ[/tex]
on halving the reaction, enthalpy also becomes half
[tex]\frac{1}{2}CH_4(g)+O_2(g)\rightarrow \frac{1}{2}CO_2(g)+H_2O(l)[/tex] [tex]\Delta H=-445kJ[/tex]
Thus The reaction of one mole of oxygen [tex](O_2)[/tex] releases 445 kJ of energy.
Review the following chemical equation: Find the molar ratio between C6H6 to
carbon dioxide, CO2. 2C6H6 + 1502 YEILDS 6H20 - 12C02
Answer:
[tex]\frac{1}{6}[/tex]
Explanation:
Molar ratio is defined as the ratio of number of moles of reactants or products in a balanced chemical equation.
In this balanced equation, the number of C6H6 molecules react to form 12 CO2 molecules.
Thus, the molar ratio between C6H6 to carbon will be equal to 2 moles of C6H6 divided by 12 moles of CO2
[tex]\frac{2}{12}\\\frac{1}{6}[/tex]
Why is the reaction SO2 + H20 → H2SO2 not balanced?
A. The oxygen atoms are in two molecules on one side, but one in
the other.
O
B. There are more molecules on one side than on the other.
O
C. There are more oxygen atoms on one side than on the other.
O
D. The sulfur atom is in different places in reactant and product
molecules
SUBMIT
Answer: C
# The main reason why the reaction above can not be balanced is:
This chemical reaction SO2 + H2O -> H2SO2 is not correctly written.
It must be: SO2 + H2O -> H2SO3
Explanation:
Note 1:
H2SO2 can be produced by the other chemical reaction:
2H2O + SCl2 -> 2HCl + H2SO2
....
Note 2: Answer A is false
As you can see in the reaction SO2 + H2O -> H2SO3, the oxygen atoms are in two molecules on one side, but one in the other - However, this reaction is written correctly.
Note 3: Answer D is false
Of course the Sulfur atom must be placed in different places: in reactant and product molecules.
Note 4: Answer B is false
There are different kinds of chemical reactions, and this is normal that there are more molecules on one side than on the other.
The answer is C
The correct way to balance the reaction, would be to write it as SO2 + H2O → H2SO3
Answer A is incorrect.
The oxygen atoms in the reaction SO2 + H2O -> H2SO3 are in two compounds on one end but on the other, it is in just one.
Answer D is wrong.
The sulfur atom has to be in the reactants and the products.
Answer B is not correct.
There are many types of chemical reactions . One side commonly has more atoms than the other.
List and describe the steps of energy transfers that occur that allow a digital recording to be played through a speaker and ultimately become sound waves.
Answer:
1) Sound waves are stores as electrical signal in the digital recording.
2) the electrical signal of the digital recording is transcribed and sent to the voice coils.
3) the voice coil changes this electrical signal into varying magnetic fields.
4) The magnetic field pushes and pulls the diaphragm of the speakers.
5) the pushing and pulling of the diaphragm generates sound waves in the speaker.
Which situation describes why a rock sinks in water?
A. Air pressure is greater than the buoyant force.
B. The force of gravity is greater than the buoyant force.
c. The buoyant force is greater than the force of gravity.
D. The rock is less dense than water.
Answer:
b
Explanation:
B. If the sand you ran across has a specific-heat capacity of 835 J/(kgºc),
how much energy must be added to a 2-kilogram pile of it to increase its
temperature from 40°C to 50°C? Show your work. (3 points)
Answer: 16700 Joules
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
[tex]Q=m\times c\times \Delta T[/tex]
Q = Heat absorbed = ?
m = mass of sand = 2 kg
c = heat capacity = [tex]835J/kg^0C[/tex]
Initial temperature = [tex]T_i[/tex] = [tex]40^0C[/tex]
Final temperature= [tex]T_f[/tex] = [tex]50^0C[/tex]
Change in temperature ,[tex]\Delta T=T_f-T_i=(50-40)^0C=10^0C[/tex]
Putting in the values, we get:
[tex]Q=2kg\times 835J/kg^0C\times 10^0C[/tex]
[tex]Q=16700J[/tex]
16700 J of energy must be added to a 2-kilogram pile of it to increase its temperature from 40°C to 50°C
Which of these Electromagnetic waves has the most kinetic energy and can be
dangerous?
O radio waves
O gamma rays
O ultraviolet waves
O visible light
Answer:
Gamma Rays.
Explanation:
Gamma-ray photons have the highest energy in the EMR spectrum and their waves have the shortest wavelength.
NEED HELPPP PLSSSSSSSSSS
Fossil fuels, like coal, oil, and natural gas, are huge, carbon-rich deposits that essentially trapped carbon for millions of years (until humans started burning them for energy).
True or False
Answer:
True!
Explanation:
Fossil fuels are carbon based compounds present deep in the earth left millions of years ago.
hope it helps!
please helpppppppppp
Select the TRUE statements about the carbon cycle
The carbon cycle is the process in which carbon travels from the atmosphere into organisms and the Earth and then back into the atmosphere.
Plants take carbon dioxide from the air and use it to make food.
Animals eat food and the carbon is stored in their bodies or released during cellular respiration.
Water (H2O) is cycled around the Earth
the carbon cycle is the process in which carbon travels from the atmosphere into organisms and the earth and then back into the atmosphere
Is the equation Zn+HCl > ZnCL2+H2 unbalanced or balanced
Answer:
unbalanced
Explanation:
Cl and H have an extra atom
- Hope that helps! Please let me know if you need further explanation.
how does atomic spectrum differ from continuous spectrum
Answer:
A continuous spectrum is a record formed by collecting light of all frequencies traveling through space together. ... A line spectrum is a record formed by collecting light emitted from excited atoms whose electrons are falling back down to lower energy states.
Explanation:
how many Atoms of chlorine Cl are there in 3.45 mol Cl?
Answer:
2.078x10^24
Explanation:
No. of atoms of chlorine = 3.45 x 6.022x 10 ^23 x 1
= 2.078x10^24
( to find no. of atoms of, heres the formula i was taught No. of atoms = no. of moles x Avogadros constant x no. of atoms in the formula of compound)
A typical cell phone uses wavelength of 0.36meters. How much energy does this wave have?
Answer:
55×10^-26 J
Explanation:
We can calculate the energy of the wave from
E= hc/λ
Where
h= Planks constant = 6.6×10^-34 Is
c= speed of light = 3×10^8 ms-1
λ= wavelength of the wave = 0.36 metres
Recall that cell phone use radio waves which belong to the electromagnetic spectrum hence it must possess the speed of light.
E= 6.6×10^-34 × 3×10^8/ 0.36
E= 55×10^-26 J
Hence the energy possessed by 0.36 meters wavelength radio waves is 55×10^-26 J
The reaction for the combustion of methane is shown below. If 28.70g of methane
reacts with 51.40g of oxygen, how much water will be produced? Record your
answer with 2 decimal places.
CH
+
20,
oxygen
CO2
carbon dioxide
+ 2H,0
water
methane
Answer:
2.888mm needs for the reaction
How much NaOH (in grams) is needed to prepare 463 mL of solution with a pH of 10.020?
Answer: [tex]1.94\times 10^{-3}g[/tex] of NaOH
Explanation:
pH or pOH is the measure of acidity or alkalinity of a solution.
pH is calculated by taking negative logarithm of hydrogen ion concentration.
[tex]pH=-\log [H^+][/tex]
Putting in the values:
[tex]10.020=-\log[H^+][/tex]
[tex][H^+]=9.55\times 10^{-11}[/tex]
[tex][H^+][OH^-]=10^{-14}[/tex]
[tex][OH^-]=\frac{10^{-14}}{9.55\times 10^{-11}}=1.05\times 10^{-4}M[/tex]
[tex]NaOH\rightarrow Na^++OH^-[/tex]
[tex]Molarity=\frac{moles\times 1000}{\text {Volume in ml}}[/tex]
[tex]1.05\times 10^{-4}M=\frac{moles\times 1000}{463ml}[/tex]
moles = [tex]4.86\times 10^{-5}[/tex]
Mass of [tex]NaOH=moles\times {\text {Molar mass}}=4.86\times 10^{-5}\times 40=1.94\times 10^{-3}g[/tex]
Thus [tex]1.94\times 10^{-3}g[/tex] of NaOH is needed to prepare 463 mL of solution with a pH of 10.020
