5. When calcium carbonate is heated, the following reaction occurs:
CaCOJ – CaO + COz (a)
The standard enthalpy of reaction for each substance is shown below.
Substance
AH, (kJ/mol)
-1206.9
-635.1
CO2 (9)
-393.5
What statements correctly classifies the decomposition of calcium carbonate
reaction?
CaCO3 (5)
CaO(s)
A-The reaction is endothermic because energy is released during the
reaction.
B-The reaction is endothermic because energy is absorbed during the
reaction.
C-The reaction is exothermic because energy is released during the
reaction.
D-The reaction is exothermic because energy is absorbed during the
reaction.
Answer:
B-The reaction is endothermic because energy is absorbed during the
reaction
Explanation:
CaCO3 -> CaO + CO2
endothermic means cooling
its decomposition of limestone to calcium oxide (quicklime) and carbon dioxide on heating
byjus
which of the following chemical symbol is that of an element with six electrons in the outermost shell a)Ca b)Cl c)Ne d)S
Answer:
S
Explanation:
Using periodic table (see those little numbers in the upper right? Those are electron 'shells' .... look at the bottom one)
Ca has 2 Cl has 7 Ne has 8 S has 6 in the outermost shell
What is the phase of water at 0.25 atm and 0°C?
what mass of Al w(molar mass 78g/mol) would have to be descomposed to produce 100 grams of Al203
Answer:
57.4 g
Explanation:
30.4 g Al will produce 57.4 g Al 2 O 3 30.4 g O 2 will produce 64.6 g Al
2 O 3 .The limiting reagent is aluminum, and the maximum amount of aluminum oxide that can be produced in this reaction is 57.4 g
1. What is a taste bud?
O tissues containing nerve cells for taste
another name for the tip of the tongue
O
a liquid in the mouth that breaks down food
O a molecule that allows you to taste food
O tissues containing nerve cells for taste
If 50 grams of CaCl2 is dissolved in 100g of water at 10 degrees. Is the solution saturated, unsaturated, or supersaturated?
Find solubility
Mass of solute/Mass of solvent×10050/100×10050%So half amount of solute is dissolved .
Hence the solution is saturated
Please help me with this chemistry
Answer:
57)a)increase
b)increase
c)pressure
58)
Density is d= m/vol. If a material has a mass of 65.5 g and a volume of 32.5 ml, it has a density of
Using the given formula, the density of the material is 2.015 g/mL
Calculating DensityFrom the question, we are to determine the density of the material
From the given formula
Density = Mass / Volume
And from the given information,
Mass = 65.5 g
and volume = 32.5 mL
Putting the parameters into the equation,
Density = 65.5/32.5
Density = 2.015 g/mL
Hence, the density of the material is 2.015 g/mL.
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Name the following compound:
CH₂-CH-CH₂ - CH₂ - CH3
1
2
CH₂
CH₂
Answer:
methylhexane.
Explanation:
Because thats the answer.
How can objects all be the same size but have a different mass? *help quick*
Answer:
All objects can have the same size but have a different mass!
This is true, although it sounds fake. This is one example, there is a Neutron star, and Neutron stars are as big as a city, but they have a mass which is hundreds of times greater than our sun's mass. Because of them having so much mass, they are also having so much gravitational energy, which makes them also have gravity. They're so small, but have so much mass that they can do much. Even a drop of a neutron star can punch open the earth! It's true, so yes, it is possible for objects the SAME size to be having different masses according to that example.
But let's look on how they can have different mass.
They can have different masses becase of different densities. Put a iron ball inside water, and put an apple as close to the iron ball's side, what happens? The apple floats, becuase the apple's mass is less than the water, and the iron ball's mass is MORE than the water. So, because the iron ball is denser than the apple, that's why, it has more mass than the apple. The apple isn't much dense, it isn't as dense as water or the iron ball. But the iron ball is much more denser than the water. So because of the different material densities of the material, that's why it can have different masses.
Remember to Remember those 2 examples I gave you... (neutron star vs sun, iron ball vs apple on water)
3. fill in: name the organelle or organelles that perform each of the following functions. a. _____________________ convert sunlight to chemical energy. b. the _____________________ and the _____________________ help to support the plant cell and help it to maintain its shape. c. _____________________ store food or pigments. d. the _____________________ converts food into energy. it is found in both plant cells and animal cells.
Organelles are the components of the cells with various functions and roles. The correct blanks are chloroplast, cell wall and vacuole, vacuoles, and mitochondria.
What are the organelles?The organelles are the cell components that have well-defined structures and functions to perform the designated task in the cell activity. Chloroplast is the organelle that converts solar energy into chemical energy through photosynthesis.
The cell wall and the vacuoles provide the structural framework and shape of the cell. The vacuoles also store food pigments in the cell. The mitochondria of the cell convert the food source into energy like ATP.
Therefore, the correct blanks are chloroplast, cell wall and vacuole, vacuoles, and mitochondria.
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A helium balloon in a closed car occupies a volume of 2.32 L at 40.0oC. How many moles of helium would exert 5 atm of pressure at the ideal conditions above?
Answer:
.451 mole
Explanation:
PV = n RT R = gas constany = .082057 L-Atm/K-mol T is in units Kelvin
5 *2.32 = n (.082057)(40+273.15)
n=.451 mole
What will the pressure be if 89.9 moles of argon are contained in a 12.0 L cylinder that is pressurized at a temperature of 300 K?
Done!
What is the mass of NaCl required to make 160 grams of a 12% solution of NaCl in water?
18 grams
19 grams
22 grams
24 grams
Answer: 19 grams
Explanation:
percent by mass = (mass of part)/(mass of whole) * 100
this means that in this question, 12 = x/160 * 100, where x is the amount of NaCl.
this means 12/100 = x/160, and thus x = (160)(12/100)=19.2 grams
The closest option is B.
Answer:
Second Option: 19 grams
Explanation:
Total solution weight: 160 grams
percent of NaCl in the solution: 12%
You take these two numbers and multiply them with 12 being over 100:
160 * [tex]\frac{12}{100}[/tex] = 19.2 grams
and then just round to the nearest whole number: 19 grams
What is the mechanical energy of an object?
O the sum of its thermal and chemical energy
O the sum of its potential and kinetic energy
the sum of its potential and chemical energy
the sum of its thermal and kinetic energy
Explanation:
the sum of potential and kinetic energy
atomic number of iron
Answer:
The atomic number of Fe which is iron is 26
Explanation:
What pressure is exerted by 0.375 mol of hydrogen gas in a 4.33 L container at 55.0C?
Answer:
47
Explanation:
I NEED HELP ASAP!!!!!!!!!!!!
WITHIN THE HOUR
Thanks
Answer:
E. O, S, Se, Te
Look up atomic size charts, go to row 6
Write the chemical formula for cobalt (II) bromide. Asp
Answer:
CoBr2
Explanation:
Hope it helps you :))))
have a good day
HELP PLEASE ASAP WILL MARK BRAINLIEST
what is the amount of heat required to raise the temperature of 200.0g of aluminum by 10C (specific heat of aluminum: 0.21 cal/g C)
a. 420 cal
b. 4200 cal
c. 42,000 cal
d. 420,000 cal
Please show calculations!
a radioisotope has a half life of 32 hours. if the average decay rate is 24 million decays per second on monday morning at 8 am, what was the decay rate on the previous morning at 10 am g
The decay rate of the radioisotope on the previous morning at 10 am is 38.7 million decays per second.
Initial decay rate of the radioisotopeThe initial mass of the radioisotope is calculated as follows;
N = N₀(¹/₂)^t/h
where;
h is half life = 32 hourst is time of day, from 8 am to 10 am previous day = 22 hours24 M/s = N₀(¹/₂)^(22/32)
24 M/s = N₀(0.62)
N₀ = (24 M/s)/(0.62)
N₀ = 38.7 M/s
Thus, the decay rate of the radioisotope on the previous morning at 10 am is 38.7 million decays per second.
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I NEED HELP ASAP!!!!!!!!!!!!
WITHIN THE HOUR
Thanks
Answer:
A. O, S, Se
Explanation:
They are all considered "other nonmetals," found in row 16 of the periodic table, and are chalcogens. The other options don't have as much in common.
which of the following is a compound .a)oxygen b) Magnesium c) Carbon dioxide d) Argon
Identify the choice that best completes the statement or answers the question.
12 Julia is in a car with her farther. The car is undergoing centripetal acceleration. What is happening to the car?
F The car is changing direction at a constant speed.
G The car is changing direction and speeding up.
H The car is stopping suddenly.
I The car is slowing down.
Answer:
the car is slowing down l think so
A gas occupied 780.0 mL at a temperature of 30°C. Several days later, it was measured at
a temperature of 16°C.
What volume did the gas occupy under these new conditions?
Answer:
744.0 mL
Explanation:
Formula obtained from Charles Law :
⇒ [tex]\frac{V_{1} }{T_{1} } = \frac{V_{2} }{T_{2} }[/tex]
===============================================================
Given :
⇒ V₁ = 780.0 mL
⇒ T₁ = 30 °C = 303 K
⇒ T₂ = 16 °C = 289 K
=============================================================
Solving :
⇒ V₂ = 780 × 289 / 303
⇒ V₂ = 225420 / 303
⇒ V₂ = 744.0 mL (approximately)
(iii) Describe one test for the presence of water
Answer:
Anhydrous copper sulphate.
Explanation:
In the presence of water anhydrous copper sulphate , a white powder, turns to blue.
Hydrogen gas is collected over water at a total pressure of 95.0kPa. The volume of gas collected is 28.0mL at 25.0˚C. Determine the partial pressure of the hydrogen gas if the water vapor pressure is 3.17kPa.
GAS LAW:
Given:
Unknown:
Formula:
Solution:
The partial pressure of the hydrogen gas, if the water vapor pressure is 3.17kPa is 91.83 kPa.
What is Dalton's law of gas?Dalton's law of gas states that total pressure of the mixture of gas is equal to the sun of the partial pressure of the individual gas.
Given that,
Total pressure of hydrogen gas = 95 kPa
Partial pressure of water vapor = 3.17 kPa
Partial pressure of hydrogen gas will be calculated as:
Partial pressure = 95 - 3.17 = 91.83 kPa
Hence required partial pressure is 91.83 kPa.
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Four patients have been diagnosed with medical issues. A 2-column table with 4 rows. The first column labeled Patient has entries Josh, Ashley, Ron, Lindsay. The second column labeled Issue has entries sprained finger, pregnant with an under developed fetus, kidney stones, cancer in the tissues lining the uterus. Which patients could be best helped using ultrasound technology? Josh, Ashley, and Lindsay Josh Ron Ashley, Ron, and Lindsay
Answer:
Ashley, Ron, and Lindsay
Explanation:
Ultrasound technology is used for medical purposes by a scanning machine that allows to obtain living images of the inside of the body. For the type of issues they are going trough, ultrasound technology would help patients Ashley, Ron, and Lindsay. Ashley's under-developing fetus, Ron's kidney stones and, Lindsay's uterus cancer can be monitored by using ultrasound technology.
The ultrasound technology is a medical tool which can help a physician to evaluate, diagnose and treat medical conditions. Here the patients with Ron, and Lindsay kidney stones and cancer can be detected by ultrasound technology. The correct option is D.
What is cancer?A term for the disease in which the abnormal cells divide without control and can invade nearby tissues is defined as cancer. The cancer cells can also spread to the other parts of the body through the blood and lymph systems.
Kidney stones are the hard deposits made of minerals and salts which form inside our kidneys. It is mainly caused due to little drinking of water, obesity, eating food with high salt or sugar content.
The ultrasound technology can detect cysts, tumors, obstructions or infections within or around your kidneys. It is also used by the medical professionals for many purposes including the pregnancy related problems.
Thus the correct option is D.
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Which electromagnetic wave has the least energy ? visible light microwave infrared light gramma ray
5. Consider the following experiment: A block of iron with an initial mass of 50 g is placed in a sealed container of pure oxygen. After several days, the block is red in color and has a mass of 74 g. Are these observations a violation of the law of conservation of mass? Justify your answer.
The observation in the illustration remains in accordance with the law of conservation of mass assuming that moisture is present in the container.
What is the law of conservation of mass?The law state that mass can neither be created nor destroyed. However, mass can be converted from one form to another.
In this case, the ion was placed in a container of pure oxygen. Assuming that moisture is present, iron reacts with oxygen to form rust according to the following equation:
[tex]4Fe + 3O_2 + 6H_2O --- > 4Fe(OH)_3[/tex]
The rust formed will weigh more than the initial weight of the iron.
Without the presence of moisture, one can effectively conclude that the observation violates the law of conservation of mass.
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