Answer:
From Earth, the Sun looks like it moves across the sky in the daytime and appears to disappear at night. This is because the Earth is spinning towards the east. The Earth spins about its axis, an imaginary line that runs through the middle of the Earth between the North and South poles.
Explanation:
Answer:
The Earth rotates on its axis always, so it looks like the sun is moving but it is the Earth that's moving.
Explanation:
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0.715 g of Na2CO3 xH2O is required 20mL of semi-normal hydrochloric acid solution
for complete reaction. Find the value of x
The value of x : 2
Further explanationSemi-normal Hydrochloric acid solution = 0.5 N = 0.5 M
for titration :
M₁V₁n₁=M₂V₂n₂(1=HCl,2=Na₂CO₃)
[tex]\tt 0.5\times 20\times 1=M_2\times V_2\times 2\\\\M_2V_2=5~mlmol=5.10^{-3}mol[/tex]
[tex]\tt MW=\dfrac{mass}{mol}=\dfrac{0.715}{5.10^{-3}}=143~g/mol[/tex]
MW Na₂CO₃.xH₂O=143
MW Na₂CO₃.xH₂O = MW Na₂CO₃+ MW xH₂O = 143
MW Na₂CO₃ = 106 g/mol
MW xH₂O = 18x
Equation :
[tex]\tt 106+18x=143\\\\18x=37\\\\x=\dfrac{37}{18}=2.056\approx 2[/tex]
The formation of ammonia is represented by the equation N2(g) + 3H2(g) ⇌ 2NH3(g). Determine the enthalpy of formation of ammonia given the following mean bond enthalpies (kJmol-1): N≡N 942; H-H 436; N-H 386
Answer:
[tex]\Delta _fH_{NH_3}=-66\frac{kJ}{mol}[/tex]
Explanation:
Hello!
In this case, since the study of the bond energy allows us to compute the enthalpies of some reactions, for this combination reaction by which ammonia is yielded, we understand the enthalpy of reaction equals the enthalpy of formation of ammonia, and, in terms of the bonds energy we can write:
[tex]\Delta _fH_{NH_3}=Delta _rH=\Sigma \Delta H(bonds \ broken)-\Sigma \Delta H(bonds \ formed)[/tex]
Whereas the bonds enthalpy of those bonds that get broken cover the N≡N and the three H-H bonds at the reactants side and the enthalpy of those bonds that are formed cover the six N-H bonds at the products; which means we obtain:
[tex]\Delta _fH_{NH_3}=942\frac{kJ}{mol} +3*436\frac{kJ}{mol}-6*386\frac{kJ}{mol}\\\\\Delta _fH_{NH_3}=-66\frac{kJ}{mol}[/tex]
Which differs from the theoretical value that is -46 kJ/mol.
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Hydrogen gas “fire quickly in the Hindenburg accident. In comparison, neon gas and helium gas are non-reactive. This is why helium is safe for F aircraft, and neon is safe for electrical signs. Which statement best explains why helium and neon have similar chemical properties?
They both are nonmetals. They both have few protons. They each have only one valance electron. They have the same number of valence electrons.
Answer:
They have the same number of valence electrons.
Explanation:
As a rule of thumb, elements with the same chemical properties must have the same number of valence electrons. This is why elements in the same group have similar chemical properties.
Chemical properties are predicated on the number of valence electrons in an atom. Atoms reacts with other atoms using the number of valence electrons they contain. Helium and neon are in the same group with 8 valence electrons. The valence electrons are the outermost electrons in an atom.A sample of poisonous carbon monoxide gas, CO, contains 2.50 g carbon and 3.33 g oxygen. The
unknown gas X is analyzed and it is determined to be made of 0.75 g carbon and 2.00 g oxygen. Are
these data an example of the law of definite proportions, the law of multiple proportions, or neither?
What does the data tell you about the identity of gas X?
Answer:
Explanation:
In carbon monoxide ,
2.5 g of carbon reacts with 3.33 g of oxygen
In unknown gas X ,
.75 g of carbon reacts with 2 .00 g of oxygen
2.5 g of carbon will react with 6.66 g of oxygen in X gas .
Ratio of oxygen in two compounds , reacting with same mass of carbon
= 3.33 : 6.66
= 1 : 2 , a simple ratio
It follows law of multiple proportions .
First gas is CO or carbon monoxide
X gas is CO₂ or carbon dioxide .
In this gas , ratio of oxygen reacting with same amount of carbon is doubled .
(Question) : What is the specific gravity of liquid sample with a mass
of 35.0 g and a volume of. 14.00 mL ?
Answer:
48.0g is the specific gravity of liquid sample with a mass of 35.0g and a volume of 14.00 mL
How many milliliters of alcohol are present in 720 mL of brandy?
Answer:
Answer : The volume of water and alcohol present in 675 mL of this solution is 405 mL and 270 mL respectively.
Explanation: As we are given that 40.0 % (v/v) alcohol solution. That means, 40.0 mL of alcohol present in 100 mL of solution.
Now we have to calculable the volume of alcohol in 675 mL solution.
As 100 mL of solution contains 40.0 mL of alcohol
So, 675 mL of solution contains alcohol
Thus, the volume of alcohol = 270 mL
Now we have to calculate the volume of water.
The volume of water = Volume of the solution - Volume of alcohol
Volume of water = 675 mL - 270 mL
The volume of water = 405 mL
Thus, the volume of water = 405 mL
Hence, the volume of water and alcohol present in 675 mL of this solution is 405 mL and 270 mL respectively.
The 720mL of an 80-proof brandy which is 40.0% (v/v) ethyl alcohol, contains 288 mL of ethyl alcohol.
What is volume/volume percentage?The Percent solutions can be expressed in the form of volume/volume percentage, weight/volume percentage, or, weight/weight percentage. The concentration of the solution in percentage is calculated as the fraction of the weight or volume of the solute related to the total weight or volume of the solution.
The solution where concentration requires to be represented in volume percent (v/v%) when the solute is a liquid phase. It is also applicable to the numerator and the denominator in volume units and is called volume/volume percent.
Volume percentage = (Volume of solute/volume of solution) x 100
The given brandy has ethyl alcohol the v/v % is 40 %.
It means the 40 ml of ethyl alcohol is present in the 100ml of brandy
Given the volume of brandy = 720 ml
Volume of ethyl alcohol in 720 ml of brandy = (40/100)×720 = 288 ml
Therefore, 288 ml of ethyl alcohol is present in 720 ml of brandy which is 40.0% (v/v) ethyl alcohol.
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Your question is incomplete, but most probably complete question was,
An 80 proof brandy is 40.0% (v/v) ethyl alcohol. The "proof" is twice the percent concentration of alcohol in the beverage. How many milliliters of alcohol are present in 720 mL of brandy?
calculate the heat required in joules to convert 18.0 grams of water ice at a temperature of -20 c to liquid water at the normal boiling point of water given specific heat of ice 2.09
Answer:
Explanation:
Heat required to convert ice to ice at 0⁰C
= mass x specific heat x rise in temperature
= 18 x 2.09 x 20
= 752.4 J .
heat required to convert ice at 0⁰C to water at 0⁰C
mass x latent heat of fusion
= 18 x 336
= 6048 J
Heat required to increase the temperature of water to 100⁰C
= 18 x 4.2 x 100
= 7560 J
Total heat required
7560 + 6048 + 752.4
= 14360.4 J
Determine the volume (mL) of 15.0 M sulfuric acid needed to react with 45.0 g of
aluminum to produce aluminum sulfate.
Answer:
167 mL.
Explanation:
We'll begin by calculating the number of moles in 45 g of aluminum (Al). This can be obtained as follow:
Mass of Al = 45 g
Molar mass of Al = 27 g/mol
Mole of Al =?
Mole = mass /Molar mass
Mole of Al = 45/27
Mole of Al = 1.67 moles
Next, the balanced equation for the reaction. This is given below:
2Al + 3H2SO4 → Al2(SO4)3 + 3H2
From the balanced equation above,
2 moles of Al reacted with 3 moles of H2SO4.
Next, we shall determine the number of mole of H2SO4 needed to react with 45 g (i.e 1.67 moles) of Al. This can be obtained as:
From the balanced equation above,
2 moles of Al reacted with 3 moles of H2SO4.
Therefore, 1.67 moles of Al will react with = (1.67 × 3)/2 = 2.505 moles of H2SO4.
Thus 2.505 moles of H2SO4 is needed for the reaction.
Next, we shall determine the volume of H2SO4 needed for the reaction. This can be obtained as follow:
Molarity of H2SO4 = 15.0 M
Mole of H2SO4 = 2.505 moles
Volume =?
Molarity = mole /Volume
15 = 2.505 / volume
Cross multiply
15 × volume = 2.505
Divide both side by 15
Volume = 2.505/15
Volume = 0.167 L
Finally, we shall convert 0.167 L to mL. This can be obtained as follow:
1 L = 1000 mL
Therefore,
0.167 L = 0.167 L × 1000 mL / 1 L
0.167 L = 167 mL
Thus, 0.167 L is equivalent to 167 mL.
Therefore, 167 mL H2SO4 is needed for the reaction.
410X
412
412
410
183
186
183R
Which two are isotopes?
Ground glass is a/an _______ material.
a) soft
b) opaque
c) translucent
d) transparent
Answer:
Opaque Material
Answer:
A ground glass is translucent as it allows only partial light to pass through it and forms light shadows
a sample of a gas has a volume kf 640 cm^{3} at 100°c and 1490 mmhg,what would be its volume at stp?
Answer:
V₂ = 918.1 cm³
Explanation:
Given data:
Initial volume = 640 cm³
Initial temperature = 100°C (100+273 = 373 K)
Initial pressure = 1490 mmHg (1490 /760 = 1.96 atm)
Final volume = ?
Final temperature = 273 K
Final pressure = 1 atm
Solution:
Formula:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
now we will put the values in formula.
V₂ = P₁V₁ T₂/ T₁ P₂
V₂ = 1.96 atm × 640 cm³ × 273 K / 373 K × 1 atm
V₂ = 342451.2 atm .cm³ . K / 373 K. atm
V₂ = 918.1 cm³
Nose color is an inherited trait in dogs. Two puppies from the same set of parents have different color noses. One puppy has a pink nose and one puppy has a black nose. How can puppies from the same set of parents have different color noses?
A.
The pink-nosed puppy and the black nosed puppy must not actually be related.
B.
The pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents.
C.
The pink-nosed puppy has a different number of chromosomes than the black nosed puppy.
D.
The pink nosed puppy and the black nosed puppy have different chromosomes for the two nose colors.
Answer:
I thin its B im not sure though
Explanation:
The puppies from the same set of parents have different color noses because the pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents. Thus, the correct option is B.
What is a gene?A gene is the unit of inheritance which is made up of DNA (deoxyribonucleic acid). Every person receives two copies or alleles of each gene which is inherited from each of the two parent.
Genes are made up of DNA, so each of the chromosome contains many different genes. Genes carry the information which determines the traits or characteristics that are passed on to their offspring or inherited from the parents.
The puppies from the same set of parents have different colored noses because pink-nosed puppy and the black nosed puppy inherited different combinations of the genes for nose color from their parents.
Therefore, the correct option is B.
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why is skeppdy and badboyhasloes friends
Answer:
what the answer is dream but what
Explanation:
Calculate the molarity of the sodium acetate solution as described below.
A. Convert the mass of NaC2H3O2 weighed to moles nNaC2H3O2. Show work with dimensional analysis.
B. Convert the mL of water measured to L
Answer:
This question is incomplete.
Explanation:
This question is incomplete because of the absence of given mass and volume, however, the steps below will help solve the completed question. The molarity (M) of a solution is the number of moles of solute per liter of solvent. The formula is illustrated below;
Molarity = number of moles (n) / volume (in liter or dm³)
To calculate the number of moles of NaC₂H₃O₂, we say
number of moles (n) =
given or measured mass of NaC₂H₃O₂ ÷ molar mass of NaC₂H₃O₂
The volume of the solvent must be in liter (same as dm³). Thus, to convert mL to liter, we divide by 1000
The unit for Molarity is M (Molar concentration), mol/L or mol/dm³
What volume, in L, of a 6.3 M K2SO4 solution contains 44.1 g of K2SO4?
What is the momentum of a cat of mass 4 kg that is running south with a speed of 1.5 m/s?
A. 2.7 kg•m/s south
B. 6.0 kg•m/s south
C. 8.3 kg•m/s south
D. 7.1 kg•m/s south
Answer:
option B is correct
Explanation:
momentum(p)=mv
mass= m=4 kg
velocity=v=1.5 m/s
P=4kg*1.5 m/s=6.0 kg.m/s
so option B is correct
For the chemical reaction 2HBr(aq)+Ba(OH)2(aq)⟶2H2O(l)+BaBr2(aq) write the net ionic equation, including the phases.
Answer:
2H⁺(aq) + 2OH⁻(aq) --> 2H2O(l)
Explanation:
2HBr(aq)+Ba(OH)2(aq)⟶2H2O(l)+BaBr2(aq)
We break the compounds into ions. Only compounds in the aqueous form can be turned into ions.
The ionic equation is given as;
2H⁺(aq) + 2Br⁻(aq) + Ba²⁺(aq) + 2OH⁻(aq) --> 2H2O(l) + Ba²⁺(aq) + 2Br⁻(aq)
Upon eliminating the spectator ions; The net equation is given as;
2H⁺(aq) + 2OH⁻(aq) --> 2H2O(l)
is there a relationship between the shape and polarity of the molecule
Answer:hi
Explanation:
Choose all the answers that apply.
Which of the following energy forms are involved in a nuclear power plant?
heat
sound
mechanical
electrical
nuclear
Answer:
heat, electrical, mechanical, nuclear,sound
Explanation:
The power plant is mechanicalised so it produce heat which is in form of electrical and then we start hearing sound
What volume of a 0.181 M nitric acid solution is required to neutralize 25.1 mL of a 0.167 M calcium hydroxide solution
Answer:
46.32 mL
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2HNO₃ + Ca(OH)₂ —> Ca(NO₃)₂ + 2H₂O
From the balanced equation above,
The following data were obtained:
Mole ratio of the acid, HNO₃ (nA) = 2
Mole ratio of the base, Ca(OH)₂ (nB) = 1
Next, we shall write out the data obtained from the question. This includes:
Molarity of the acid, HNO₃ (Ma) = 0.181 M
Volume of the base, Ca(OH)₂ (Vb) = 25.1 mL
Molarity of the base, Ca(OH)₂ (Mb) = 0.167 M
Volume of the acid, HNO₃ (Va) =?
Finally, we shall determine the volume of the acid, HNO₃ as shown below:
MaVa/ MbVb = nA/nB
0.181 × Va / 0.167 × 25.1 = 2/1
0.181 × Va / 4.1917 = 2
Cross multiply
0.181 × Va = 4.1917 × 2
0.181 × Va = 8.3834
Divide both side by 0.181
Va = 8.3834 / 0.181
Va = 46.32 mL
Therefore, the nitric acid, HNO₃ required for the reaction is 46.32 mL
There are two cups of water. The cups of water must have the same average Kinetic energy if they have the same ___
Answer:
Temperature and Heat
Explanation:
Proportional to the average kinetic energy of the molecules in a substance.
what mass of potassium chlorate should be required to produce 113 L of oxygen O2. measured at STP g
Answer:
411.6 g
Explanation:
The equation for the decomposition of potassium chlorate to produce oxygen is given as;
2KClO3 --> 2KCl + 3O2
From the stochiometry of the reaction 2 mole of KClO3 produces 3 mol of O2
At STP,
1 mol = 22.4L
3 mol = x
x = 67.2L
2 mole of KClO3 produces 67.2L of O2
How many moles would produce 113L?
2 = 67.2
x = 113
x = 3.36 moles
Moles can be converted to mass using;
Mass = moles * Molar mass
Mass = 3,36 * 122.5 g/mol
Mass = 411.6 g
Please help!!!!!
Please help!!!!!
Answer:
1.B
2.A
3. B
Explanation:
1. A chemical bond is the physical phenomenon of chemical substances being held together by attraction of atoms to each other through sharing
2. so 2 is electrons of one atom are transferred permanently to another atom.meaning the answer is A
3. is When atoms combine by forming covalent bonds, the resulting collection of atoms is called a molecule. We can therefore say that a molecule is the simplest unit of a covalent compound.
A chemical bond is an attraction between two atoms.
A ionic bond is A bond formed when atoms transfer electrons.
A sample of laughing gas occupies 0.250 L at 14.7 psi and - 80.0°C. If the volume of the gas is 0.375 L at 25.0°C, what is the pressure?
Answer:
Final pressure =P₂ = 15.13 psi
Explanation:
Given data:
Initial volume = 0.250 L
Initial pressure = 14.7 psi
Initial temperature = -80.0°C (-80.0 +273 = 193 K)
Final volume = 0.375 L
Final temperature = 25.0°C (25+273 =298 k)
Final pressure = ?
Solution:
P₁V₁/T₁ = P₂V₂/T₂
P₁ = Initial pressure
V₁ = Initial volume
T₁ = Initial temperature
P₂ = Final pressure
V₂ = Final volume
T₂ = Final temperature
Now we will put the values in formula.
P₂ = P₁V₁ T₂/ T₁ V₂
P₂ = 14.7 psi × 0.250 L × 298 K / 193 K × 0.375 L
P₂ = 1095.15 psi .L. K / 72.375 K.L
P₂ = 15.13 psi
In order for radiation to transfer heat, A electromagnetic waves must be transmitted
B objects must be in direct physical contact C particles must circulate and move in a liquid or gas D thermal energy must move from cold to hot objects.
Answer : A
Explanation
B- conduction
c - convection
D heat transfer
Answer:
d
Explanation:
Calculate the standard potential for a cell that employs the over-all cell reaction: 2Al(s) + 3 I2(s)→2 Al+3 + 6 I- From reduction potential table: Al+3 (aq) + 3e- → Al(s) -1.66 V I2(s) + 2e- → 2I- -0.54 V
Answer:
Explanation:
2Al(s) + 3 I₂(s) → 2 Al⁺³ + 6 I⁻
Aluminium is oxidised and iodine is reduced .
so cell potential = Ereduction - Eoxidation
Al⁺³ + 3e = Al - 1.66 V
I₂ + 2 e = 2 I⁻ 0.54 V
= .54 - ( - 1.66 )
= 1.66 + .54
= 2.2 V
The overall standard cell potential for the given cell that employs the overall cell reaction is; E°_cell = 2.20 V
We are given the cell reaction;
2Al (s) + 3I₂ (s) → 2Al⁺³ + 6I⁻
We are given reduction potential as;
Al⁺³(aq) + 3e⁻ → Al(s) ;E°_red = -1.66 V
However, the standard reduction potential for the reverse of the oxidation reaction is;
Al → Al⁺³(aq) + 3e⁻ ;E°_ox = 1.66 V
We are also given;
I₂ + 2e⁻ = 2I⁻ ;E°_red = 0.54 V
To get overall standard cell potential, we will add the cell potentials to get;
E°_cell = E°_ox + E°_red
E°_cell = 1.66 + 0.54
E°_cell = 2.20 V
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Which situation describes a chemical change?
A. Clay pressed into a mold takes on the shape of the mold.
B. Baking soda added to vinegar gives off carbon dioxide gas.
C. Chocolate changes from a solid to a liquid when heated.
D. Rubbing pencil lead onto paper changes the color of the paper.
Answer:
C
Explanation:
I just took the test
Answer:
B
Explanation:
Does the radiation from the sun travel to earth in varying frequencies
Explanation:
The gamma ray photons make their arduous journey to the surface of the Sun, they are continuously absorbed by the solar plasma and re-emitted to lower frequencies. ... By the time they get to the surface, their frequencies are mostly only within the IR/visible light/UV spectrum. Nov28,2020
Which of the substances have polar interactions (dipole–dipole forces) between molecules?
A. Cl2
B. F2
C. ClF
D. NF3
Answer:
F2 and Cl2 are non-polar because both contains same atom and they have same electronegativity.
ClF and NF3 have polar interactions because there is electronegativity difference between atoms.
Explanation:
The covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements, such as hydrogen H, oxygen O and chlorine Cl. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas. The shared electron pair is common to the two atoms and holds them together.
Electronegativity is defined as the ability of an element to attract the electrons that link it to another element.
The covalent bond between two atoms can be polar or nonpolar.
When two atoms have different electronegativities, the one with the highest electronegativity will attract the electrons towards each other, giving rise to two opposite charges on the bond. That is, this generates that in a polar molecule there is separation between positive and negative charges. The bonds will be all the more polar the greater the difference in electronegativity between the bound atoms.
On the other hand, the non-polar covalent bond occurs between atoms of the same element or between atoms with very little electronegativity difference. It is thus characterized to molecules or bonds that do not exhibit any polarity.
A molecule is a dipole when there is an asymmetric distribution of electrons because the molecule is made up of atoms of different electronegativity. That is, dipole is formed when the molecule is polar.
So, dipole-dipole forces are forces of attraction between polar molecules. These molecules attract when the positive end of one of them is close to the negative of the other.
Given the above, F₂ and Cl₂ are non-polar molecules and ClF and NF₃ are polar molecules. Then ClF and NF₃ have polar interactions (dipole-dipole forces). -Brainly user
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