Answer:
152
Explanation:
since it weighs 1.9 grams per [tex]cm^{3}[/tex] we get 80*1.9 which is 152 grams
Geetha took some grains of boiled rice in test tube A and Tina took boiled and chewed rice in test tube B. Both of then poured 1-2 drops of iodine solution into the test tubes. What would they have observed? Give a reason for your answer.
Answer:
Test tubes A and B turn a darker blue color.
Explanation:
Based on the information provided in the question it can be said that they should have noticed that Tube A and Tube B turned a dark blue color. This is because the starch turns the solution in the test tubes into a dark blue color due to the negative reaction caused by the conversion of starch present in salivary amylase
What can happen when tectonic plates move a few centimeters?
Answer:
whole continents can move.
Q2. Which of these is a mixture?
1.chlorine
2.sodium chloride solution
3.sodium
4,sodium chloride
Why does the structure of the plasma membrane make this type of transport necessary for fluids
Answer: because the phospholipid bilayer formed by these interactions makes a good barrier between the interior and exterior of the cell, because water and other polar or charged substances cannot easily cross the hydrophobic core of the membrane.
Explanation:
evidence of a chemical change includes?
Answer:
Change of color, change in temperature, change of energy or loss heat, odor etc....
Two boxes need to be moved into storage. Jamal and Jude each want to move a box. The force of gravity on both the boxes is 50 N. Jamal is lifting with a force of 60 N, and Jude is lifting with a force of 45 N. Which best describes the movement of the boxes? Jamal moved his box to storage, but Jude could not move his. Jamal and Jude can successfully move each box into storage. Jamal could not move his box to storage, but Jude could. Neither Jamal nor Jude could move the boxes into storage.
Answer: 80
Explanation:
Answer:
Jamal moved his box to storage, but Jude could not move his.
Explanation:
The force they exert needs to be higher than the force of gravity in order for them to move the boxes. Jamal's force is 60N, which is 10N above the force of gravity on the box, which is 50N. However, Jude's force is only 45N and that is lower than 50N, so he won't be able to move the box while Jamal can.
why should we store Phosphorus in water
The reason we should store phosphorous in water is because it will ignite on contact with air
what is pyruvate converted to
Answer:
gold
Explanation:
How will you test for the gas which is liberated when hcl reacts with an active metal ?
Oxygen is released into the atmosphere by _____.
respiration
photosynthesis
denitrification
fixation
Answer:
your answer will be photosynthesis
Explanation:
A 15.50 gram sample of a gas exerts a pressure of 1.40 atmospheres when held in an 8.00 liter at 22 °C. What is the molar mass (grams/mol) of the gas?
Answer:
33.5 g/mol
Explanation:
PV=nRT
(1.40 atm)(8.00 L)=n(0.08206)(295 K)
n=0.463 mol
15.50 g/0.463 mol=33.5 g/mol
How do greenhouse gases such as CO2 and N2O contribute to an increase in Earth’s atmospheric temperature?
A.
Greenhouse gases interact with infrared photons and reflect them back to Earth’s surface.
B.
Greenhouse gases chemically react with one another, releasing heat in the process.
C.
Greenhouse gases agitate visible light photons, increasing the photons’ temperature and motion energy.
D.
Greenhouse gases generate internal heat through radioactive decay, similar to the core of Earth.
Answer:
The answer is A
Explanation:
The earth naturally maintains the heat energy balance by absorbing a sufficient amount of sunlight energy by the terrestrial land and then reverting back the excess sunlight energy back to the space. The increase in abundance of greenhouse gases in the atmosphere results in absorption of sunlight energy which contains infrared photons this is responsible for increasing the global temperature levels hence, responsible for global warming. These infrared photons are reflected to the earth surface instead of sending back to the space. This is responsible for disturbing the heat balance.
Greenhouse gases interact with infrared photons and reflect them back to earth’s surface, hence option A is correct.
How does greenhouse gases rise in earth’s atmosphere?The burning of fossil fuels, logging of forests, and raising of livestock all have a rising impact on the climate and temperature of the planet.
This increases the greenhouse effect and causes global warming by adding a significant amount of greenhouse gases to those that are already present in the atmosphere.
The earth naturally maintains the balance of heat energy by receiving enough solar energy through the terrestrial land and then returning any excess energy to space.
Therefore, greenhouse gases such as CO₂ and N₂O interact with infrared photons and reflect them back to earth’s surface.
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Allicin is the compound responsible for the characteristic smell of Garlic. An analysis of the compound gives the following percent composition by mass; C = 44.4 percent, H = 6.21 percent. S = 39.5 percent, O = 9086 percent. Calculate its empirical formula. What is its molecular formula given that its molar mass is about 162 g?
Answer:
The empirical formula is same as the molecular formula = C6H10S2O
Explanation:
we start by dividing the percentage of each of the elements by their atomic mass
Carbon = 44.4/12 = 3.7
Hydrogen = 6.21/1 = 6.21
Sulphur = 39.5/32 = 1.234375
oxygen = 9.89/16 = 0.618125
That of oxygen is smallest so we divide all by that of oxygen
C = 3.7 / 0.618125 = 6
H = 6.21/ 0.618125 = 10
S = 1.234375/ 0.618125 = 2
Automatically, oxygen is 1
So the empirical formula is;
C6H10S2O
Let’s get its molecular formula. We multiply each of the subscript by the number;
(72 + 10 + 64 + 16)n= 162
162n = 162
n = 1
So the molecular formula is same as the empirical formula
Explain why covering something with a blanket can put out a fire
Answer:
No oxygen
Explanation:
when something is covered in a blanket it prevents the fire from being able to have any oxygen
Answer:
Its called smothering the fire
Explanation:
A fire needs three things to burn always: fuel, oxygen, and a heat source. Eventually the heat source will not be an issue, but the oxygen and fuel is. If the fire is small enough throwing a blanket can quite smother it. What happens is it cuts off the oxygen supply the fire needs long enough for it to die out.
Given the following chemical equation at equilibrium: H2(g) + I2(g) ↔2HI(g) + heat. If the temperature is raised, in what direction will the equilibrium shift?
Answer: The reaction will shift in left or backward direction.
Explanation:
Any change in the equilibrium is studied on the basis of Le-Chatelier's principle. This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.
For the given equation:
[tex]H_2(g)+I_2(g)\rightleftharpoons 2HI(g)+heat[/tex]
As the given reaction is exothermic as the heat is released in the reaction. When the temperature is raised , the reaction will shift in a direction where temperature is decreasing and that is the reverse reaction which is endothermic in nature.
Thus the reaction will shift in left or backward direction.
Which is one way that waves erode coastlines?
Answer:
Four main processes erode the destructive waves; hydraulic action, compression, abrasion and attrition. Hydraulic Action is the sheer force of water crashing off the coastline causing the material to dislodge and be carried away by the sea.
Answer:
a
Explanation:
What is the total energy change for the following reaction: H2 + I2 -> 2HI?
Given:
H-H bond: 436 kJ/mol
I-I bond: 151 kJ/mol
H-I bond: 297 kJ/mol
A. +7 kJ/mol
B. +297 kJ/mol
C. -290 kJ/mol
D. -7 kJ/mol
Energy change is the conversion of the energy stored in reactants to products. In the reaction between hydrogen and iodine, the energy change is -7 kJ/mol. Thus, option D is correct.
What is total energy change?Total energy change is the conversion of the energy from a substance to another when the reactant undergoes modification to produce a product.
The reaction is given as,
H₂ + I₂ → 2HI
In the reaction, the bonds between H-H and I-I are broken to release energy that produces two H-I bonds as the product.
Given,
H-H bond = 436 kJ/mol
I-I bond = 151 kJ/mol
H-I bond = 297 kJ/mol
So, 436 kJ/mol + 151 kJ/mol - 2x297 kJ/mol = -7 kJ/mol
Therefore, -7 kJ/mol is the total energy change in the reaction involving hydrogen and iodine.
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Complete the table to summarize the properties of the different subatomic particles by typing in 'yes"
or "no."
A
Answer:
A=yes
B=yes
Explanation:
Just did the same thing
Protons and neutrons are made of quarks but electrons are not. So A is yes, B is Yes and C is No.
What are quarks?
Quarks are extremely small substances which join with each other by extremely strong forces and makeup neutrons and protons of the atom. They combine in a similar way that the protons and neutrons combine to form the nucleus of an atom.
Quarks are categorized in flavours and there are 6 different types of flavours of quarks. The flavours differ from each other on the basis of their charge and mass.
The six flavours of quarks are grouped as three pairs. These are up and down, charm and strange and top and bottom.
Quarks are defined as true elementary particles. They have no defined structure and cannot be subdivided into smaller particles.
Therefore, the correct option is A is yes, B is Yes and C is No.
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Kaia, a chemical engineering graduate, has documented all titration procedures in her project report. She refers to this report while performing titrations in her laboratory. This is an example of _____. Select one: a. muted knowledge b. implied knowledge c. tacit knowledge d. explicit knowledge
Answer:
The correct option is;
d. Explicit knowledge
Explanation:
Explicit knowledge is the knowledge that can be easily articulated documented stored in a retrieval system accesses, transmitted and shared with others
Tacit knowledge is the skill developed by an individual based on actual experience such that such knowledge comprise of both facts and perspectives
Hence explicit knowledge and tacit knowledge are complementary
The operations performed by Kaia include documentation, storing in a retrieval system (her project report) and accessing what she documented, this is an example of explicit knowledge.
7. What volume of a 0.10 mol/l HCl solution is needed to neutralize 10 ml of a 0.15
mol/l LiOH solution (5 points)
Answer: The volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml
Explanation:
To calculate the volume of acid, we use the equation given by neutralization reaction:
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1,M_1\text{ and }V_1[/tex] are the n-factor, molarity and volume of acid which is [tex]HCl[/tex]
[tex]n_2,M_2\text{ and }V_2[/tex] are the n-factor, molarity and volume of base which is LiOH.
We are given:
[tex]n_1=1\\M_1=0.10mol/L\\V_1=?mL\\n_2=1\\M_2=0.15mol/L\\V_2=10mL[/tex]
Putting values in above equation, we get:
[tex]1\times 0.10\times V_1=1\times 0.15\times 10\\\\V_1=15mL[/tex]
Thus the volume of a 0.10 mol/l HCl solution needed to neutralize 10 ml of a 0.15 mol/l LiOH solution is 15 ml
A catalyst can only be used once.
True
False
Answer:
False
Explanation:
Catalysts are reusable because they keep the chemical reactions moving without being consumed.
A solution is made by mixing 114.g of benzene C6H6 and 83.g of acetyl bromide CH3COBr. Calculate the mole fraction of benzene in this solution. Round your answer to 3 significant digits.
A solution is made by mixing 114.g of benzene C6H6 and 83.g of acetyl bromide CH3COBr, the mole fraction of benzene in this solution is 1.45mol.
What is molar mass ?The term molar mass is defined as the compound is often calculated by adding the quality atomic masses in g/mol of the constituent atoms.
Molar mass of CH3COBr,
Molar Mass = 2 × MM(C) + 3 × MM(H) + 1 × MM(O) + 1 × MM(Br)
= 122.944 g/mol
Molar mass of C6H6,
MM = 6 × MM(C) + 6 × MM(H)
= 6 × 12.01 + 6 × 1.008
= 78.108 g/mol
n(CH3COBr) = mass/molar mass
= 83 /122.944
= 0.675
n(C6H6) = mass/molar mass
= 114 / 78.108
= 1.45
n(CH3COBr),n1 = 0. 675mol
n(C6H6),n2 = 1. 45mol
Thus, the mole fraction of benzene in this solution is 1.45mol.
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A.
B.
C.
D.
what could be the correct answer? Help me please
Answer:
A
Explanation:
Answer:
a
Explanation:
What is the molar mass of silver oxide (Ag2O)
Answer:
231.735 g/mol
Explanation:
I NEED HELP PLEASE, THANKS! :)
A manufacturing company is trying to produce a lightweight but strong cart for use by home gardeners. Which metal—titanium (Ti), iron (Fe), or zinc (Zn)—would be the best for this application and why?
Answer:
Titanium; lowest density
Explanation:
The cart would use the same volume of metal, no matter which one it was made of.
If weight were the only consideration, the company would choose the metal with the lowest density.
The values I find for the metals are
Ti 4.5 g/cm³
Fe 7.9 g/cm³
Zn 7.1 g/cm³
Titanium would be the best metal for this application.
Answer:
Titanium would be the best metal for this application because it is a low density metal that is still strong and ductile
Explanation:
The temperature of a piece of copper with a mass of 95.4g increases from 25 degrees Celsius to 48.0 degrees Celsius when the metal absorbs 849 J of heat. What is the specific heat capacity of copper?
Answer:
The answer is 3.87 J/g°C
Explanation:
Here is the equation we are going to use:
[tex]C=\frac{q}{mT}[/tex]
C= specfic heat in J/g°C
q = heat in joules (J)
m = mass in grams (g)
T = change in temperature
Here is what is given:
q = 849 J
m = 95.4 g
T = 48.0 - 25.0 = 23°C
Find:
Specific heat capacity in J/g
The first thing we are going to do is plug everything into the equation:
[tex]C = \frac{849J}{(9.54g)(23degreesC)}[/tex]
Then we are going to solve for C
[tex]C = \frac{849J}{219.42gC} = 3.87 J/gCelsius[/tex]
Hope this helps!
Answer:
The answer is 3.87 J/gC
Read the following statements carefully: X: It is a thick black coloured liquid which is obtained from coal.Y: It was used earlier in railway engines to produce steam to run trains.Z : It is used to run heavy vehicles such as buses, trucks, tractors, etc.X, Y and Z respectively are
Options are not given in the question. The complete question is as follows:
Read the following statements carefully: X: It is a thick black coloured liquid which is obtained from coal.Y: It was used earlier in railway engines to produce steam to run trains.Z : It is used to run heavy vehicles such as buses, trucks, tractors, etc.X, Y and Z respectively are
A. a. Coal tar b. Coal c. Diesel
B. a. Coal b. Paraffin wax c. Petrol
C. a. Coke b. Coal tar c. Kerosene
D. a. Coke b. Coal c. Coal tar
Answer:
A. a. Coal tar b. Coal c. Diesel
Explanation:
Coal Tar is a thick black or dark brown colored liquid obtained from coal. Coal Tar consists of hydrocarbons and free carbon extracted from coal using a process of destructive distillation. So, X is coal tar.
Earlier coal was used to produce steam to run steam engine trains. Air flows are allowed to burn coal hotter, then the hot coal turns water to steam and helps in the locomotive steam engine to run. So, Y is coal.
Deisel is used to run heavy vehicles such as buses, trucks, tractors, etc. because diesel burns at slow speed and produces a higher torque that can move heavy automobiles. So, Z is deisel.
Hence, the correct option is A.
How can you contribute at your own level to save the environment? Plz say the anwer
Answer:
Some things you could do are recycle more, contribute to organizations that support saving the environment, finding alternate transportation methods such as riding a bike or walking, and finally, you could volunteer.
A solution of Co(NO₃)₂ is electrolyzed using a 15.0A current for 1.00 hour and Co(s) is produced at the cathode. Calculate the moles of electrons that was used to electrolyze the solution? Calculate the moles and mass of Co(s) produced at the cathode?
Answer:
1. 0.56 mole of electron.
2. 0.28 mole of Co .
3. 16.52g of Co.
Explanation:
The following data were obtained from the question:
Current (I) = 15A
Time (t) = 1 hr = 1 x 60 x 60 = 3600secs
Next, we shall determine the quantity of electricity, Q flowing in electrolyte. This is illustrated below:
Quantity of electricity (Q) = current (I) x Time
Q = It
Q = 15 x 3600
Q = 54000C.
1. Determination of the moles of electrons used to electrolyzed the solution. This is illustrated below:
96500C = 1 mole of electron
Therefore, 54000C = 54000/96500 = 0.56 mole of electron.
Therefore, 0.56 mole of electron was used to electrolyze the solution.
2. Determination of the number of mole of Co produced at the cathode. This is illustrated below:
At the cathode:
Co2+ + 2e —> Co
From the balanced equation above,
2 moles of electron produce 1 mole of Co.
Therefore, 0.56 mole of electron will produce = 0.56/2 = 0.28 mole of Co.
Therefore, 0.28 mole of Co is produced at the cathode.
3. Determination of the mass of Co produced at the cathode. This can be achieved by doing the following:
Molar mass of Co = 59g/mol
Number of mole of Co = 0.28 mole
Mass of Co =..?
Mass = mole x molar mass
Mass of Co = 0.28 x 59
Mass of Co = 16.52g
Therefore, 16.52g of Co is produced at the cathode.
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PLEASE HELP...
Ethyl acetate is a sweet-smelling solvent used in varnishes and fingernail polish remover. It is produced industrially by heating acetic acid and ethanol
together in the presence of sulfuric acid, which is added to speed up the
reaction. The ethyl acetate is distilled off as it is formed. The equation for the
process is as follows.
CH3COOH + CH3CH2OH --> CH3COOCH2CH3 + H2O
Determine the percentage yield in the following cases:
a. 68.3 g of ethyl acetate should be produced but only 43.9 g is recovered.
b. 0.0419 mol of ethyl acetate is produced but 0.0722 mol is expected. (Hint:
Percentage yield can also be calculated by dividing the actual yield in moles
by the theoretical yield in moles.)
c. 4.29 mol of ethanol is reacted with excess acetic acid, but only 2.98 mol of
ethyl acetate is produced.
d. A mixture of 0.58 mol ethanol and 0.82 mol acetic acid is reacted and 0.46
mol ethyl acetate is produced. (Hint: What is the limiting reactant?)
Answer:
The percentage yields are as follows :
a) 64.28%
b) 58.03%
c) 69.46%
d) 79.31%
Explanation:
The percentage yield is the ratio of the actual yield of a product to the expected or theoretical yield expressed as a percentage.
Percent yield = actual yield/theoretical yield x 100%
a) from the question, expected yield is 68.3 g whilst the actual yield is 43.9 g
therefore,
Percentage yield = 43.9 g/68.3 g x 100%
= 0.64275 x 100%
= 64.28%
b) From the question, expected yield is 0.0722 mol while the actual yield is 0.0419 mol. Therefore
Percentage yield = 0.0419 /0.0722 x 100%
= 0.58033 x 100%
= 58.03%
c) A limiting reactant is the reactant is is completely used in a recation to form a product. That is, it is the reactant that is not in excess.
From the equation of the reaction :
CH3COOH + CH3CH2OH --> CH3COOCH2CH3 + H2O
1 mole of ethanol reacts with 1 mole of acetic acid to give 1 mole of ethyl acetate.
From the question, ethanol is the limiting reactant because it is not in excess. Hence,
4.29 mole of ethanol should produce 4.29 mole of ethyl acetate (expected yield).
However only 2.98 mol of ethyl acetate is produced (actual yield)
Percentage yield = 2.98mol/4.29 mol x 100%
= 0.69463 x 100%
= 69.46%
d) From the question, acetic acid is in excess hence ethanol is the limiting reactant
therefore from the equation of the reaction:
1 mole of ethanol reacts with 1 mole of acetic acid to give 1 mole of ethyl acetate.
0,58 mol of ethanol should produce 0.58 mol of ethyl acetate (expected yield)
But 0.46 mol of ethyl acetae was produced (actual yield)
Percentage yield = 0.46mol /0.58 mol x 100%
= 0.79310 x 100%
= 79.31%