Answer:
Number of moles = 0.057 × 10⁻⁷ mol
Explanation:
Given data:
Mass of SiO₂ = 3.4 × 10⁻⁷ g
Number of moles = ?
Solution:
Number of moles = mass/molar mass
Molar mass of SiO₂ = 60 g/mol
by putting values,
Number of moles = 3.4 × 10⁻⁷ g / 60 g/mol
Number of moles = 0.057 × 10⁻⁷ mol
Pure sodium metal reacts violently with water according to the equation below
Na + H2O - NaO + H2
17 mol
If 0.75 mol of Na is placed in 500 g of
H,O how many moles of hydrogen
gas will be produced?
0.75 mol
28 mol
1.5 mol
Answer:
0.75 mol
Explanation:
Given data:
Number of moles of Na = 0.75 mol
Mass of water = 500 g
Moles of hydrogen gas produced = ?
Solution:
Chemical equation:
Na + H₂O → NaO + H₂
Number of moles of water:
Number of moles = mass/molar mass
Number of moles = 500 g/ 18 g/mol
Number of moles = 27.8 mol
now we will compare the moles of hydrogen gas with both reactant.
Na : H₂
1 : 1
0.75 : 0.75
H₂O : H₂
1 : 1
27.8 : 27.8
sodium will act as limiting reactant it produced small number of moles of hydrogen gas as compared to water.
Thus, number of moles of hydrogen gas are 0.75 mol.
Condensation is a phase change from?
Answer:
gas to liquid
Explanation:
think of water vapor condensing on glass when you breathe on it for a while.
Solids, liquids and gases are all
considered to be forms of matter.
Each of these take up space and also
exhibit what other significant
characteristic?
A. color
B. smell
C. texture
B. mass
Answer:
mass
Explanation:
hope this helps you!!
a) Calculate the standard reaction entropy for the combustion of methane to carbon dioxide and liquid water at 298 K. b) Calculate the standard reaction entropy for the hydrolysis of liquid water to form oxygen and hydrogen gas. c) Do your results in (a) and (b) agree with the general rule that reaction entropies are positive if there is a net formation of gas in a reaction, and negative if the is a net reduction of gas?
Answer: (a) [tex]\Delta S^{0}[/tex] = - 242.2J/K.mol
(b) [tex]\Delta S^{0}[/tex] = 163.34J/K.mol
(c) Yes
Explanation: Entropy is the measure of randomness or disorder of a system. Standard Entropy has the symbol [tex]S^{0}[/tex].
Mathematically, Entropy is defined as
[tex]\Delta S^{0}=\Sigma S^{0}(products)-\Sigma S^{0}(reagents)[/tex]
Each substance has its own entropy value.
(a) Combustion of Methane:
[tex]CH_{4}+2O_{2}[/tex] ⇒ [tex]CO_{2}+2H_{2}O[/tex]
Using standard entropy table, entropy will be:
[tex]\Sigma S^{0}(products)=214+2(69.91)[/tex] = 353.8
[tex]\Sigma S^{0}=186.264+2(205.138)[/tex] = 596.54
[tex]\Delta S^{0}=[/tex] 353.8 - 596.54
[tex]\Delta S^{0}=[/tex] - 242.2
Standard Entropy for combustion of methane is [tex]\Delta S^{0}=[/tex] - 242.2 J/K.mol.
(b) Hydrolysis of Water:
[tex]H_{2}O_{(l)}[/tex] ⇒ [tex]H_{2}_{(g)}+1/2O_{2}_{(g)}[/tex]
[tex]\Sigma S^{0}(products)=130.684+0.5(205.138)[/tex] = 233.253
[tex]\Sigma S^{0}(reagents)=69.91[/tex]
[tex]\Delta S^{0}=[/tex] 233.253 - 69.91
[tex]\Delta S^{0}=[/tex] +163.34
Standard Entropy for hydrolysis of water is [tex]\Delta S^{0}=[/tex] + 163.34 J/K.mol
(c) Yes, the results prove the general rule: Reactions Entropies are positive for net formation of gas and negative for net reduction of gas. This happens because, as entropy is the measure of disorder, the entropy for gases are greater than for liquids and solids. So, when there is formation of a gas, Entropy increases and when there isn't, entropy decreases.
Which material would get electrons from the source to the load the fastest
Answer:
Copper
Explanation:
Because copper conducts a lot of electricity, and gets the most electrons
exhibits the highest intermolecular
forces of the states of matter.
Answer:
Solid
Explanation:
In solid there are strong intermolecular forces present as compared to liquid and gas. This is why solid are in more packed form as compared to liquid and gas. In liquid and gas intermolecular forces are week that's why molecules are away from each other and occupy more space.
Properties of gases:
Molecule of gases randomly move everywhere and occupy all available space.
Gases don't have definite volume and shape and take the shape and volume of container in which it present.
Their densities are very low as compared to the liquid and solids.
Gas molecules are at long distance from each other therefore by applying pressure gases can be compressed.
The very weak inter molecular forces are present between gas molecules.
Properties of Liquid:
Liquid have definite volume but don't have definite shape.
Their densities are high as compared to the gases but low as compared to the solids.
In liquid, molecules are close to each other and have greater inter molecular forces as compared to the gas molecules.
Properties of solids:
Solids have definite volume and shape.
In solids molecules are tightly pack and very close to each other.
Their melting and boiling point are every high.
The densities of solids are also very high as compared to the liquid and gas.
There are very strong inter molecular forces are present between solid molecules.
Answer:
A: Solid
Explanation:
Correct with Acellus
Which one is true? Elements in the same row have the same number of:
Explanation:
Elements in same row (i.e, from left to right) have the same number of electron shells.
how many moles of NO are formed from 2.5 moles of NO2 if there is plenty of water present
Moles of NO formed : 0.833
Further explanationGiven
2.5 moles of NO2
Required
moles of NO formed
Solution
Reaction
3 NO₂(g) + H₂O(l) = 2 HNO₃(aq) + NO(g)
The reaction coefficient in a chemical equation shows the mole ratio of the compounds in the reactants and products
From the equation, mol ratio of NO₂ and NO = 3 : 1, so moles of NO :
[tex]\tt moles~NO=\dfrac{1}{3}\times 2.5\\\\moles~NO=0.833[/tex]
HELPPPPPP
is this
1:conduction
2:radiation
3:convection
Answer:
Radiation
Explanation:
Sun rays shine on earth. Thats radiation.
Which element has the highest electronegativity?
Answer:
fluorine
Explanation:
has the highest electronegativity?
what tools are used specifically for earth science
Geologic Tools. Geologists use a lot of tools to aid their studies. Some of the most common tools used are compasses, rock hammers, hand lenses, and field books.
hope this helped <3
Which is a pure substance?
They are chemically bonded together.
They can be classified as pure substances.
They have fixed ratios between their components.
They can be separated by physical processes.
Answer: C. They have fixed ratios between their components.
what is the dilution factor if you add a 0.1ml aliquot of a specimen to 9.9 dilutent
The dilution factor : 100
Further explanationThe dilution factor(DF) : ratio of concentration of stock solution and diluted solution or ratio of the volume of final solution to the initial volume from stock solution
From equation of dilution :
M₁V₁=M₂V₂
[tex]\tt DF=\dfrac{M_1}{M_2}=\dfrac{V_2}{V_1}[/tex]
Volume of aliquot = 0.1 ml
Volume of diluent = 9.9 ml
So final volume :
[tex]\tt V_f(final~volume)=volume~aliquot+volume~diluent\\\\V_f=0.1+9.9=10~ml[/tex]
The dilution factor (DF) :
[tex]\tt D_f=\dfrac{V_f}{V_i}\\\\D_f=\dfrac{10}{0.1}=100[/tex]
In the reaction C + O2 → CO2, 18 g of carbon react with oxygen to produce 72 g of carbon dioxide. What mass of oxygen would be needed in the reaction?
18 g
54 g
72 g
90 g
Answer:
54g of O2 reacted in the reaction
Answer:
54g
Explanation:
Which event would most likely lead to a thunderstorm g i v i n g b r a i n l e s i t HELP
--
Answer:
A
Explanation:
hope it helps
Answer:
A
Explanation:
I got right
someone on this planet please help me with this vocab
Answer:
1 - concentrated solution
2- dilute solution
3- solubility
4- saturated solution
5- supersaturated solution
6- unsaturated solution
7- acid
8- base
9- corrosive
10- indicator
Explanation:
If 33.9g NaCl are mixed into water and the total mass is 578g, what is the CHANGE in freezing if Kb= - 1.82C/M (molal)? Assume NaCl does not dissociate in solution.
Answer:
-1.82 °C
Explanation:
Step 1: Given data
Mass of NaCl (solute): 33.9 gMass of water (solvent): 578 g = 0.578 kgFreezing point depression constant for water (Kb): -1.82 °C/mStep 2: Calculate the molality of the solution
We will use the following expression.
m = mass of solute / molar mass of solute × kg of solvent
m = 33.9 g / 58.44 g/mol × 0.578 kg
m = 1.00 m
Step 3: Calculate the freezing point depression (ΔT)
The freezing point depression is a colligative property that, for a non-dissociated solute, can be calculated using the following expression:
ΔT = Kb × m
ΔT = -1.82 °C/m × 1.00 m
ΔT = -1.82 °C
how is the strength of an acid affected by the number of hydrogen ions it contains
More the no. of hydrogen ions more is the solution acidic.
pH means the power of hydrogen that determines the concentration of hydrogen ions or the level of acidiy or basicity of a solution.
so more the hydrogen ions more will be the Power of Hydrogen (pH) and thus more wil be the acidity.
Please help this affects my grade a lot and im confused
Double Replacement/Combustion I need to find the product of each one
zinc oxide + Cobalt(III) nitrite
Calcium hydroxide + phosphoric acid
Copper(I) dichromate + Iron(III) arsenate
Hydrochloric acid + aluminum hydroxide
1 ) Cobalt(II) nitrate react with nitrate zinc(II) to produce cobalt(III)-zinc oxide, nitrogen dioxide and oxygen
2Co(NO3)2 + Zn(NO3)2 → Co2ZnO4 + 6NO2 + O2
2) Calcium hydroxide react with phosphoric acid to produce calcium, hydrogen phosphate and water
Ca(OH)2 + H3PO4 → CaHPO4 + 2H2O
3) Copper(II) dichromate will react with Iron(III) arsenate to form Copper(II) Arsenate and Iron(III) dichromate
3Cr2CuO7 + 2AsFeO4 → Cu3(AsO4)2 + Fe2(Cr2O7)3
Reaction Type : Double Displacement
4) aluminium hydroxide and hydrochloric acid react to form aluminium chloride and water
Al(OH)3 + 3HCl → AlCl3 + 3H2O
Please help, it’s much appreciated
If the hydrogen ion concentration,
[H+], in a solution is 2.65 x 10-2 M,
what is [OH-]?
Answer: acidic
Explanation:
Answer:
3.77 x 10^-13 M
Explanation:
Help me as soon as possible I’m gonna dieeee
Someone plz help me write notes (images attached)
Answer:
I'm not going to give you notes but I'm going to give you a tip for notes take what you think is the most important thing about the text and basically paraphrase it into your own words if that helps
How do balanced equations demonstrate the law of conservation of mass?
Answer:
Every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. ... When an equal number of atoms of an element is present on both sides of a chemical equation, the equation is balanced.
Explanation:
so have a great day
Can someone help me I only have 5 minutes left.
What does a useful scientific explanation include ??
Answer: scientific explanation
Explanation:
A really good scientific explanation should do two main things: It should explain all the observations and data we have. It should allow us to make testable predictions that we can check using future experiments.
Magnesium has a density of 1.738 g/cmº at 25°C. What is the mass of a block of
magnesium that has a volume of 743 cm??
Answer:
87.50g(1cm^3/1.1738g)=50.345 cm^3
Explanation:
volume units id in cubic centimeters
how dose dissolving sugar in water show that matter is made up of particles
Answer:
When sugar dissolves, the sugar particles separate from each other and mix with the water particles. When the sugar particles separate, the smaller water particles fit into the spaces between the larger sugar particles. The water and sugar particles are attracted to each other, so they move closer together when they mix.
Explanation:
: )
A paint chip is placed in ethanol and curls what type of paint is it
Answer:
it is probably acrylic or latex
Explanation:
There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, the type of paint is acrylic or latex.
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
An ionic compound is a metal and nonmetal combined compound. Ionic compound are very hard. They have high melting and boiling point because of strong ion bond. If the chip remains flat when put in ethanol, it is probably an oil-based paint. If the chip curls, it is probably acrylic or latex. So, The type of paint is acrylic or latex.
Therefore, the type of paint is acrylic or latex.
To learn more about chemical compound, here:
brainly.com/question/26487468
#SPJ2
Does iron always have a charge of 2+ when it forms an ion
Answer:
Roman numeral notation indicates charge of ion when element commonly forms more than one ion. For example, iron(II) has a 2+ charge; iron(III) a 3+ charge.
Explanation:
a wooden block with a mass of 2.0kg starts from at the top of an inclined plane and ends with a force of 25N at the bottom what was the rate of acceleration of the block
Answer:
Force F = 20N .
Mass m = 2.0 kg
Initial velocity u = 0
acceleration, a = 10m/s
2
t = 1 sec.
Now Refer to the attachment, See the free body diagram of the block.
Force works on the block:-
Weight, W = mg
W = 2 × 10
W = 20N (which is Downward)
Normal force N = mg cos37
N = 20 × 0.80
N = 16 N. (perpendicular & upward to the plane )
Here Applied Force, P = 20N (which is down along the plane)
Now For Final Speed, We know the formula:-
v = u + at
v = 0 + 10 × 1
v = 10 m/s
the Distance travelled s = ut + 0.5 at×t
s = 0 + 0.5 ×10×1×1
s = 5 m.
Now,
(a) So work done by the force of gravity in 1 sec. = F × d
⇒20 N × 5m
⇒100 J.
(b) Here the weight act as downward, so distance travelled in downward.
⇒5 × sin37
⇒5 × 0.6
⇒3 m.
so work done by gravity,
⇒20 N × 3 m
⇒60 J.
(c) Now, work done by all the forces
⇒change in Kinetic energy
⇒
2
1 m(v2
−u 2
)
⇒0.5×2.0×(10 2
−0 2 )
⇒ 100 J.
⇒W.D by frictional force
= work was done by all forces -( work was done by Normal force + work done by applied force + work done by gravity )
= 100 J - (100 + 60 +0 )
= 100 - 1
Hope this helps you≅