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.
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
Calculate the heat evolved for the reaction of 2.50 L of B2H6 with 5.65 L of Cl2 according to the following reaction. Both reactant gases are initially at STP
B2H6(g) + 6 Cl2(g) —> 3 BCl3(g) + 6HCl(g) Delta H = -1396 kJ
The heat evolved with the [tex]\rm B_2H_6[/tex] has been 58.637 kJ.
From the balanced chemical equation, 1 mole of [tex]\rm B_2H_6[/tex] reacts with 2 moles of Chlorine to give 3 moles of boron chloride and 6 moles of HCl,
The chlorine has been required in double the quantity of boron hexahydride.
The moles of Chlorine has been the limiting reactant.
The chlorine that has been responsible for the reaction with [tex]\rm B_2H_6[/tex] will be:
6 Chlorine = 1 [tex]\rm B_2H_6[/tex]
5.65 L Chlorine = [tex]\rm \dfrac{5.65}{6}[/tex]
5.65 L Chlorine = 0.942 L [tex]\rm B_2H_6[/tex].
The moles of [tex]\rm B_2H_6[/tex] can be calculated as:
1 Mole = 22.4 L
Moles of [tex]\rm B_2H_6[/tex] in 0.942 L = 0.042 mol.
The heat evolved for 1 mole [tex]\rm B_2H_6[/tex] has been -1396 kJ.
The heat evolved for 0.042 mol [tex]\rm B_2H_6[/tex] = 0.042 × -1396 kJ.
The heat evolved = 58.637 kJ.
The heat evolved with the [tex]\rm B_2H_6[/tex] has been 58.637 kJ.
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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
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?
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 .
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:
What is the % of H20 in Sodium carbonate decahydrate, Na2CO3 • 10H2O
Answer:
Element Symbol # of Atoms
Sodium Na 2
Cobalt Co 3
Hydrogen H 20
Oxygen O 10
Explanation:
What volume, in L, of a 6.3 M K2SO4 solution contains 44.1 g of K2SO4?
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
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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
A ballon that contains 0.75 l of gad at 25 c is cooled to - 100 c. Calculate the new volume of the baloon
Answer:
0.44L
Explanation:
Given parameters:
Initial volume = 0.75L
Initial temperature = 25°C = 273 + 25 = 298K
Final temperature = -100°C = 273 + (-100) = 173K
Unknown:
New volume of the balloon = ?
Solution:
According to Charles's law;
"the volume of a fixed mass of a gas varies directly as its absolute temperature if the pressure is constant".
Mathematically;
[tex]\frac{V_{1} }{T_{1} }[/tex] = [tex]\frac{V_{2} }{T_{2} }[/tex]
V and T are temperature values
1 and 2 are the initial and final states
Insert the parameters and solve;
[tex]\frac{0.75}{298}[/tex] = [tex]\frac{V_{2} }{173}[/tex]
298V₂ = 129.75
V₂ = 0.44L
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
Hope this helps!how does conc.H2SO4 reacts with sugar?
is there a relationship between the shape and polarity of the molecule
Answer:hi
Explanation:
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]
Which problem that the most scientists believe is partly caused by carbon dioxide?
Answer:
Climate change
Explanation:
Climate change is primarily a problem of too much carbon dioxide (CO2) in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests
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
why is skeppdy and badboyhasloes friends
Answer:
what the answer is dream but what
Explanation:
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.PLZZZZZZZZZZZ
NEED HELP ASAP!!!!!
Answer:
wersawess. uioiiiuioii
Explanation:
shhshsbshsjbsnsbxbxjzn, jznshdkbdjdjsnsj
Answer:
ok
asap what is the meaning of it?
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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28.The chemical formula of a compound indicates
the source of the elements in the compound.
b. how elements are joined in the compound.
the alchemy symbols for the elements in the compound.
d. the relative proportions of the elements in the compound.
Answer:
d. the relative proportions of the elements in the compound.
Explanation:
The chemical formula of a compound indicates the relative proportions of the element in the compound.
The chemical formula of a compound is a representation which shows all the elements therein and the mole relationship between them expressed as subscripts. For example HCl, contains one mole of hydrogen and 1 mole of Cl.Using the Rydberg equation, calculate the energy for the following electronic transitions in a hydrogen atom and label each as an absorption or an emission. When calculating, watch your signs!
n = 3 → n = 1
a. Energy calculation
b. absorption or emission?
Answer:
-1.94 * 10^-18 J
Since the electron moved from a higher to a lower energy level (n = 3 → n = 1) it is an emission.
Explanation:
From Rydberg equation;
E = -RH(1/n^2final - 1/n^2initial)
For a transition from n = 3 → n = 1
RH = 2.18 * 10^-18 J
E = -(2.18 * 10^-18) (1/1^2 - (1/3^2)
E = -(2.18 * 10^-18) (1-1/9)
E= -(2.18 * 10^-18) (8/9)
E = -1.94 * 10^-18 J
410X
412
412
410
183
186
183R
Which two are isotopes?
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
which two smaller groups is the animals kingdom is divided into
A. sponges and arthropods
B. vertebrates and invertebrates
C. ectotherms and endotherms
D. class and order
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
How long is a wave traveling at 120 m/s if it has a frequency of 30 Hz?
Answer:
4 m
Explanation:
