Answer:
2.04 x 10²⁴ molecules
Explanation:
Given parameters:
Mass of Be(OH)₂ = 145.5g
To calculate the number of molecules in this mass of Be(OH)₂ we follow the following steps:
>> Calculate the number of moles first using the formula below:
Number of moles = mass/molarmass
Since we have been given the mass, let us derive the molar mass of Be(OH)₂
Atomic mass of Be = 9g
O = 16g
H = 1g
Molar Mass = 9 + 2(16 + 1)
= 9 + 34
= 43g/mol
Number of moles = 145.5/43 = 3.38mol
>>> We know that a mole is the amount of substance that contains Avogadro’s number of particles. The particles can be atoms, molecules, particles etc. Therefore we use the expression below to determine the number of molecules in 3.38mol of Be(OH)₂:
Number of
molecules= number of moles x 6.02 x 10²³
Number of molecules= 3.38 x 6.02 x 10²³
= 20.37 x 10²³ molecules
= 2.04 x 10²⁴ molecules
Ammonia reacts with oxygen to produce nitric acid (HNO3) and water. What mass of nitric acid, in grams, can be made from 405 g of ammonia?
Express the mass to three significant figures and include the appropriate units.
The mass of nitric acid that can be produced from 405 g of ammonia is approximately 1500 g, when rounded to three significant figures.
Explanation:To determine the mass of nitric acid that can be made from 405 g of ammonia, we first need to write the balanced chemical equation for the reaction between ammonia and oxygen:
4NH3 + 5O2 -> 4HNO3 + 6H2O
This equation tells us that 4 moles of ammonia (NH3) react to produce 4 moles of nitric acid (HNO3).
The molar mass of ammonia (NH3) is approximately 17.03 g/mol. Therefore, 405 g of ammonia is equivalent to 23.77 moles (405 g / 17.03 g/mol). So, we can produce the same amount of moles of nitric acid (23.77 moles).
The molar mass of nitric acid (HNO3) is approximately 63.01 g/mol. Therefore, the mass of nitric acid that can be made from 405 g of ammonia is approximately 1497 g (23.77 moles x 63.01 g/mol). This value should be reported to three significant figures: 1500 g.
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If Maria winks exactly 5 times every minute and she sleeps
exactly 8 hours a day, how many times does Maria wink every
day?
Answer:
4800 times does Maria wink every day.
Explanation:
Number of time Maria winks= 5 times in minute = 5 winks/min
Number of hours she sleeps in day = 8 hours
1 day = 24 hours
Number of hours when Maria is not sleeping = 24 hour - 8 hour = 16 hours
1 hour = 60 minutes
16 hours = 16 × 60 min = 960 min
number of winks in 960 minutes:
[tex]960 min\times 5 winks/min=4800 winks[/tex]
4800 times does Maria wink every day.
She winks 192 times every day.
This is just basic arithmetic.
In a day, we have 24 hours.
Now, 60 minutes make an hour.
Thus,
Number of minutes in a day = 60 × 24 = 1440 minutes
She sleeps 8 hours a day.
This is same as; 8 × 60 = 480 minutes
Thus, total time she is awake in a day = 1440 - 480 = 960 minutes
She winks every 5 minutes.
Thus, number of winks = 960/5 = 192 winks
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What's the inner core of the Jovian planets made of? A. Hydrogen compounds, solid rock, and metals B. Bacteria fossils, hydrogen compounds, and ice crystals C. Helium gas, hydrogen gas, and rocks D. Metals, helium gas, and hydrogen gas
Answer:
A. Hydrogen compounds, solid rock, and metals
Explanation:
The Jovian planets, also referred to as outer planets, are the four planets that are in the outer half of the solar system. These planets are gas giants, and they are mostly made out of gases, having much larger sizes and masses than the terrestrial planets. The inner cores of these planets also differ from the cores of the terrestrial planets. The inner cores of these planets are made out of rocks, metals, and hydrogen compounds. In general their cores are the size of the Earth, though they are much more massive.
Answer: The inner core of the Jovian planets are made of: Hydrogen compounds, solid rock, and metals.
what is the concentration of an NaOH solution that requires 50 mL of a 1.25 M H2SO4 solution to neutralize 78.0 ml of NaOH
Answer:
The answer is the concentration of an NaOH = 1.6 MExplanation:
The most common way to solve this kind of problem is to use the formula
C₁ * V₁ = C₂ * V₂In your problem,
For NaOH
C₁ =?? v₁= 78.0 mL = 0.078 L
For H₂SO₄
C₁ =1.25 M v₁= 50.0 mL = 0.05 L
but you must note that for the reaction of NaOH with H₂SO₄
2 mol of NaOH raect with 1 mol H₂SO₄
So, by applying in above formula
C₁ * V₁ = 2 * C₂ * V₂ (C₁ * 0.078 L) = (2* 1.25 M * 0.05 L)C₁ = (2* 1.25 M * 0.05 L) / (0.078 L) = 1.6 MSo, the answer is the concentration of an NaOH = 1.6 M
Write the chemical symbols for three different atomic cations that all have 13 protons.
The chemical symbols for three different atomic cations that all have 13 protons:-
[tex]Al^{+1} ,Al^{+2} ,Al^{+3} [/tex]
Atomic number:-
The atomic number defines the number of protons in an atom.
Atomic cations are [tex]Al^{+1} ,Al^{+2} ,Al^{+3} [/tex]
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What is the name of the ionic compound RbCI
If a pond is located in an area with significant amounts of air pollution, which health measure would be most directly affected?
A: pH
B: nitrates
C: turbidity
D: dissolved oxygen
If a pond is located in an area with significant amounts of air pollution then pH would be most directly affected.
What is pH?The term pH is a measurement that indicates the acids and bases of a particular solution.
In this case, the pond represents an aqueous solution whose pH can change in different situations.The pH can change by different pollutants in an environment because it modifies the acid/basic level of a solution.In conclusion, if a pond is located in an area with significant amounts of air pollution then pH would be most directly affected.
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Tutorial queshers Set 1
| Why does molecule become a chiral if has a Plane of symmetry even through it has stereocenter
Answer:
Here's what I get.
Explanation:
Consider the molecule shown below.
It has two chiral centres, labelled R and S, and an internal mirror plane that makes the right and left halves of the molecule mirror images of each other.
If we pass a beam of plane-polarized light through the sample, the R portion of the molecule will rotate the light in a certain direction.
However, the S portion will rotate the light by the same amount in the opposite direction.
The two effects cancel each other, so the molecule has no net effect on plane-polarized light.
Even though the molecule has two chiral centres, it is achiral because it has an internal plane of symmetry.
If I have 340 mL of a 1.5 M NaBr solution, what will the concentration be if I add 560 mL water to it?
Answer:
0.5667 M ≅ 0.57 M.
Explanation:
It is known that the no. of millimoles of a solution before dilution is equal to the no. of millimoles of the solution after the dilution.It can be expressed as:(MV) before dilution = (MV) after dilution.
M before dilution = 1.5 M, V before dilution = 340 mL.
M after dilution = ??? M, V after dilution = 340 mL + 560 mL = 900 mL.
∴ M after dilution = (MV) before dilution/(V) after dilution = (1.5 M)(340 mL)/(900 mL) = 0.5667 M ≅ 0.57 M.
Bromine can be classified as a
Answer:
Halogen / salt-former
Explanation:
Bromine is classified as an element in the 'Halogens' section which can be located in group 7 of the Periodic Table. The term "halogen" means "salt-former" and compounds containing halogens are called "salts".
As the average kinetic energy increases in a material what other energy also increases
Potential energy thats what i think anyone else got a diffrent answer
Increasing the average kinetic energy of a material's particles raises the temperature, which in turn raises the substance's internal thermal energy.
When the temperature of a material is increased, this results in an increase in the average kinetic energy of the particles composing that material. As the average kinetic energy goes up, the temperature of the substance rises. Consequently, if a substance's temperature is elevated, its internal energy also goes up, which can be observed as an uptick in both the kinetic and potential energies of the particles in the material.
Therefore, when we discuss an increase in kinetic energy, we are generally referring to an increase in thermal energy
Specifically, in the context of a chemical reaction, higher kinetic energy means that the molecules are moving more rapidly, resulting in more frequent and more energetic collisions. Even though an increase in collision frequency does not guarantee a reaction will occur, it does increase the probability that the molecules will bump into each other with the necessary orientation and energy to react. This, in turn, can increase the rate of the reaction.
A 520-gram sample of seawater contains 0.317 moles of NaCl. What is the percent composition of NaCl in the water?
The answer is in the photo.
Answer:
3.56 %
Explanation:
Percent composition of NaCl = [tex]\frac{mass of NaCl}{mass of sea water }[/tex] x 100
Mass of sea water = 520 g
Moles of NaCl = 0.317 mol
Molar mass of NaCl = 58.44 g/mol
Mass of NaCl = moles of NaCl x Molar mass of NaCl
= 0.317 mol x 58.44 g/mol = 18.52 g
Percent composition of NaCl = [tex]\frac{18.52 g}{520 g}[/tex] x 100 = 3.56 %
WORTH 99 POINTS
What are the negative effects of deforestation on the environment? Check all that apply.
air pollution
desertification
water pollution
urbanization
climate change
desertification, urbanization, and climate change(more carbon dioxide).
Answer:
Desertification and climate change and urbanization
what type of circuit is Illustrated?
A.a close parallel circuit
B.a close series circuit
C.an open parallel circuit
D.an open series circuit
Answer: D. an open series circuit
What happened to a balloon when it is put in freezer
The frozen balloon shrank because the average kinetic energy of the gas molecules in a balloon decreases when the temperature decreases. This makes the molecules move more slowly and have less frequent and weaker collisions with the inside wall of the balloon, which causes the balloon to shrink a little.
What is the electron structure of a sodium atom?
A. 1s22s22p63s1
B. 2s22s22p63s1
C. 1s22s22p63s6
D. 1s12s22p63s1
Answer:
1s22s22p63s1 is the electronic configuration of sodium.
Explanation:
There are 11 electrons in Sodium ( find this on the periodic table).
Then you need to arrange the electrons in the orbitals around the nucleus.
The structure would be written as A. 1s^22s^22p^63s^1
What is the pH of a 0.00750 M solution of hydrochloric acid, HCl? (2 points) pH = 1.45 pH = 1.93 pH = 2.12 pH = 3.07
Ph = - Log (Hcl)
= - Log (0.00750)
= 2.12
Ph = 2.12
Answer: pH = 2.12
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 and pOH is calculated by taking negative logarithm of hydroxide ion concentration.
[tex]pH=-\log [H^+][/tex]
[tex]pOH=-log{OH^-}[/tex]
[tex]pH+pOH=14[/tex]
Give :[tex][H^+][/tex] = 0.00750
[tex]pH=-log[0.00750][/tex]
[tex]pH=2.12[/tex]
When magnesium chloride reacts with water, 5.85)L HCLg is produced. How many moles of HCL is produced
Answer: 650 moles
Explanation: so converted in grams just to make it easy for me, its 5850 g of water right, which is 325 moles of water
so here's the balanced equation
MgCl2 + H20 ==> 2HCl + MgO
thus 1 mole of h20 gives us 2 moles of hcl, so 325 x 2 = 650 moles of hcl
2. Calculate the molarity of 500.0 grams of Li2S in a total volume of 4.44 liters?
[Li2S molar mass = 46.0 grams/mol
Answer:
2.448 M ≅ 2.45 M.
Explanation:
Molarity (M) is the no. of moles of solute that dissolved in 1.0 L of the solution.
M = (no. of moles of solute)/(V of the solution (L).
M = (mass/molar mass) Li₂S / (V of the solution (L))
∴ M of Li₂S = (500.0 g/46.4 g/mol)/(4.44 L) = 2.448 M ≅ 2.45 M.
Answer:
The molarity of 500.0 grams of Li₂S in a total volume of 4.44 liters is 2.448 [tex]\frac{moles}{liter}[/tex]
Explanation:
Molarity (M) is the number of moles of solute (substance that dissolves in a solvent with which it forms a solution, is in a smaller proportion) that are dissolved in a given volume.
Molarity is expressed by the following expression:
[tex]M=\frac{number of moles of solute}{ volume of solution}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex]
Then, you must first know the amount of moles that represent the 500 g of Li₂S. For that, a rule of three is applied knowing the molar mass: if 46 g is 1 mol of Li₂S, 500 g of the compound, how many moles are they?
[tex]moles=\frac{500 g*1mole}{46 g}[/tex]
moles≅10.87
It is now possible to calculate molarity by applying the definition:
[tex]M=\frac{10.87 moles}{4.44 L}[/tex]
M= 2.448 [tex]\frac{moles}{liter}[/tex]
The molarity of 500.0 grams of Li₂S in a total volume of 4.44 liters is 2.448 [tex]\frac{moles}{liter}[/tex]
Which of the following materials is most effective for stopping gamma radiation? Please explain your answer
single sheet of paper
one cm of water
several cm of lead
single sheet of aluminum foil
Answer:
Option C= several cm of lead.
Explanation:
we know there are three types of radiations emit by the atoms to attain the stability. These three radiations are alpha, beta and gamma. Gamma radiations are high energy radiations. These radiations are travel at the speed of light. Gamma radiations can penetrate into the many materials. These radiations are also used to treat the cancer.
These radiations can not be stopped by the single sheet of paper or the water. Lead is used for the protection against gamma radiations because of its high molecular density. The lead apron are used by the person when treated with gamma radiations. Lead shields are also used in the wall, windows and doors of the room where gamma radiations are treated, in-order to protect the surroundings. While the sheet of aluminium is used to block the beta radiations.
Answer: cm of lead
Explanation: gradpoint (aluminum only stops alpha and beta)
Which sentence is a scientific statement?
Answer:
It depends what are the choices that are given.
Answer:
Explanation:
Which sentence is a scientific statement?
A. Long hair looks better than short hair.
B. Brick structures insulate better than wooden structures.
C. Milkshakes should always be sweetened with honey.
D. There is a large, apelike creature living in the Himalayas.
4. Why is cooking an endothermic process?
A) Uncooked food contains more chemical energy than cooked food.
B) Energy is continuously added for the chemical reactions to take place.
C) The chemical reactions involved in burning fuels release energy
Answer:
Hi there!
The answer that best fits is B: Energy is continuously added for the chemical reactions to take place.
Explanation:
Endothermic means energy GOING IN not releasing.
Answer: The correct answer is Option B.
Explanation:
Endothermic reactions are defined as the reactions in which energy is absorbed by the system. The total enthalpy of the reaction comes out to be positive.
Exothermic reactions are defined as the reactions in which energy is released by the system. The total enthalpy of the reaction comes out to be negative.
Cooking is a type of endothermic reaction because in this process, energy is given to the uncooked food continuously. Energy is getting absorbed by the food for the chemical reactions to take place.
Thus, the correct answer is Option B.
A student increases the temperature of a 417 cm3 balloon from 65°C to 126°C. What will the new volume of the balloon be?
Answer:
492.3 cm³.
Explanation:
We can use the general law of ideal gas: PV = nRT.where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
If P and n are constant, and have different values of T and V:(V₁T₂) = (V₂T₁).
V₁ = 417.0 cm³, T₁ = 65°C + 273 = 338 K.
V₂ = ??? cm³, T₂ = 126°C + 273 = 399 K.
∴ V₂ = (V₁T₂)/(T₁) = (417.0 cm³)(399 K)/(338 K) = 492.3 cm³.
Answer:
492.3 cm³.
Explanation:
a mixture of ozone and oxyen containing 20% by volume of ozone defuse through a porous in172 sec while same volume of pure oxygen took 164 sec to diffuse . calculate relative density of ozone
The relative density of ozone will be 1.5
What happens to pressure as volume increases
If the volume increases then the pressure would decrease.
Answer: So if the volume increases, the pressure decreases. ... Boyle's law states that for a fixed amount of gas in an enclosed system at constant temperature, pressure and volume are inversely proportional
Explanation:
This linear relationship between pressure and volume means doubling the volume of a given mass of gas decreases its pressure by half.
PV = c
or
P ∝ 1/V
How many molecules are in 257 grams of chlorine (Cl2)? Show your work in the space below. HELPPPP
Answer:
2.2 × 10^24 molecules
Explanation:
First of all, we need to know the molar mass of chlorine which can be found by using its atomic mass.
molar mass of Chlorine ([tex]Cl_2[/tex]) = [tex]35.453 \times 2[/tex] = 70.906 g/mol
It means that one mole of Chlorine has a mass of 70.906 g.
Number of moles present in 257 grams sample = [tex]\frac{257}{70.906}[/tex] = 3.62 moles
We know that, [tex]1mol = 6.022 \times 10^{23}[/tex]
So we will multiply the number of moles present in 257 grams of Chlorine with this number to find the number of molecules.
Number of molecules in 257 grams of Chlorine = [tex]3.62 \times 6.022 \times 10^{23}[/tex] = 2.2 × 10^24 molecules
Widespread use of fuel cell vehicles poses a danger because
fuel cells emit a greenhouse gas that endangers the ecosystem.
it is hard to build fuel cell vehicles that travel slowly enough to match speed limits.
hydrogen used to power fuel cells could run out and disappear from Earth.
it is difficult to safely transport and store hydrogen gas before it is used.
Answer:
It is difficult to safely transport and store hydrogen gas before it is used.
Explanation:
A mixture of hydrogen gas and oxygen causes an explosive reaction. Any minimal leak would mean a fire hazard. If it was in a series of storage equipment, a single explosion would lead to a series of other explosions that would lead to a massive loss of property and possibly, life.
Answer:
Widespread use of fuel cell vehicles poses a danger because
it is difficult to safely transport and store hydrogen gas before it is used.
Explanation:
A furl cell is used in a fuel cell vehicle instead of a battery.
By the use of Oxygen and compressed hydrogen electricity is generated to give power to the motor. The transportation and the process of storing hydrogen create pollutants. The primary energy which helps in the production of hydrogen is the main aspect on which the impact of the fuel cell depends upon.
4)
 The mixtures of sodium carbonate and calcium nitrate react to precipitate calcium carbonate and sodium nitrate. This reaction is shown by which balanced chemical equation?
4)
 The mixtures of sodium carbonate and calcium nitrate react to precipitate calcium carbonate and sodium nitrate. This reaction is shown by which ba.lanced chemical equation?
The reaction between Na2CO3 and Ca(NO3)2 to precipitate CaCO3 and NaNO3 is shown by balanced double diaplacement reaction.
Answer:
Na₂CO₃ + Ca(NO₃)₂ → CaCO₃ + 2NaNO₃
Explanation:
Sodium carbonate = Na₂CO₃Calcium nitrate = Ca(NO₃)₂Calcium carbonate = CaCO₃Sodium nitrate = NaNO₃The unbalanced reaction is:
Na₂CO₃ + Ca(NO₃)₂ → CaCO₃ + NaNO₃
We begin by balancing Na, so we put a coefficient of two in sodium nitrate:Na₂CO₃ + Ca(NO₃)₂ → CaCO₃ + 2NaNO₃
Ca is already balanced, there is 1 Ca atom in each side of the reaction.CO₃ is already balanced, there is 1 group in each side of the reaction.NO₃ is already balanced, there are 2 groups in each side.The reaction is now balanced.
Which prefix would appear in the IUPAC name for a covalent compound that has four atoms of a single element?
tri-
di-
tetra-
mono-
Answer:
tetra-.
Explanation:
In IUPAC system, when naming molecular compounds prefixes are used to dictate the number of a given element present in the compound:” mono-” indicates one,
“di-” indicates two,
“tri-” is three,
“tetra-” is four,
“penta-” is five,
“hexa-” is six,
“hepta-” is seven,
“octo-” is eight,
“nona-” is nine,
and “deca” is ten.
So, the right choice is: tetra-.
I Need Help With This One!!!
Answer:
Deforestation due as a result of development
Explanation:
As economies advance the need for more space to put up more infrastructure increases. This leads to the clearing of forests leaving widespread bare lands as the one shown in the picture provided, that have the long term effect of desertification.