5) answer is A
2NaHCO3(s) + 129k) - Na2CO3(s) + H2(g) + CO2(g)
This equation indicates that AH is
and energy must be
to complete the reaction.
A)
positive; added
B)
negative; added
C)
positive; released
D)
negative; released
Answer:
A) positive; added
Explanation:
Based on the reaction:
2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)
2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.
That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.
Thus, right answer is:
A) positive; added
During a reaction, H for reactants is -750 kJ/mol and H for products is 920 kJ/mol. Which statement is correct about the reaction and correctly compares the energy in bonds?
Answer:
a
Explanation:
the ones are stronger and herder to break so it will take more energy to break them then when they are made
The statement, that describes the reaction and correctly compares the energy in bonds from the given ΔH values is "It's endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed."
What is ΔH?The quantity of energy evolved during a chemical reaction is represented by ΔH, also known as enthalpy change.
An exothermic reaction is a chemical reaction in which heat energy is emitted. The value of ΔH is always negative in exothermic processes. An endothermic reaction is a chemical reaction that absorbs heat energy. The value ΔH of is always positive for endothermic reactions.
When the bonds in the reactants are broken, more energy is absorbed than is released when new bonds are created in the products, therefore the value of ΔH is always positive in endothermic reactions.
Hence the correct option is endothermic because the energy required to break bonds in the reactants is less than the energy released when the products are formed.
Learn more about ΔH here
https://brainly.com/question/16420084
#SPJ2
Discuss whether two products are required for a chemical reaction. (NEED HELP ASAP)
Answer:
Yes.
Explanation:
"These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products."
There is a beginning product, and a reactant is needed in order for something to happen.
For example, according to Newton, something cannot happen until an exterior force comes and stops/pushes it.
Sorry if this is incorrect, I am just 4th grade :(
What are the basic forces that drive the water cycle? Explain what they are.
Answer:
kcgiobb jkffiob hffyio hiiddhoo hhioiv
Answer: Have a blessed day
Explanation:
Water Cycle: Component # 1. Evaporation:
Evaporation is the process where a liquid changes from its liquid state to a gaseous state. Liquid water becomes water vapour. Temperature is the primary factor for evaporation.
During the water cycle the water of the oceans and freshwater bodies, such as lakes and rivers, is warmed by the sun and evaporates. During the process of evaporation, impurities in the water are left behind. As a result, the water that goes into the atmosphere is cleaner than it was on Earth.
Water Cycle: Component # 2. Condensation:
Condensation is the opposite of evaporation. Condensation is the process where a gas is changed into a liquid. Condensation occurs when the temperature of the vapour decreases.
The water droplets formed from condensation are very small and they remain suspended in the atmosphere. There millions of droplets of suspended water form clouds in the sky or fog at ground level. Water condenses into droplets only when there are small dusts particles present around.
Water Cycle: Component # 3. Precipitation:
When the temperature and atmospheric pressure are right, the small droplets of water in clouds form larger droplets or raindrops and it is called precipitation. The raindrops fall to earth.
As a result of evaporation, condensation and precipitation, water travels from the surface of the Earth goes into the atmosphere, and returns to Earth again.
Water Cycle: Component # 4. Surface Runoff:
Much of the water that returns to Earth as precipitation runs off the surface of the land and flows down-hill into streams, rivers, ponds and lakes. Small streams flow into the ocean. Surface runoff is an important part of the water cycle because, through surface runoff, much of the water returns again to the oceans, where a great deal of evaporation occurs.
Water Cycle: Component # 5. Infiltration:
ADVERTISEMENTS:
Infiltration is an important process where rain water soaks into the ground, through the soil and underlying rock layers. Some of this water ultimately returns to the surface at springs or in low spots downhill. Some of the water remains underground and is called groundwater.
As the water infiltrates through the soil and rock layers, many of the impurities in the water are filtered out. This filtering process helps in cleaning of the water.
Water Cycle: Component # 6. Transpiration or Evapotranspiration:
This is performed by plants. As plants absorb water from the soil, the water moves from the roots through the stems to the leaves. Once the water reaches the leaves, some of it evaporates from the leaves, adding to the amount of water vapour in the air. This process of evaporation through plant leaves is called transpiration. In large forests, an enormous amount of water will transpire through leaves.
Which of the following shows the 3 main jobs of a cell?
a
make energy, recycle all cells, dispose of cells
b
make proteins, dispose of cells, digest food
c
make energy, make proteins, make more cells
d
digest food, dispose of cells, recycle all cells
Which pH is the most acidic
Answers choices below
A. 7
B. 14
C. 0.5
D . 1
C. 0.5
This is the answer.
(assuming that the D option is 1, if it is 0.1 then the answer is 0.1)
[tex]0.5[/tex]
Explanation:
As you know that decreasing in the concentration of OH- (i.e., 14, 13, 12, 11,..) makes to increase in the concentration of H+ ions (5,4,3,2,1).
HELP!! :))
I’ll give Brainliest to whoever balances the equation and says what the theoretical and percent yields are of the equation :)
A buffer solution is prepared by adding NaC2H2O2 to a solution of HC2H2O2 (acetic acid). HC2H3O2(aq) = H+ (aq) + C2H302 - (aq) What happens if KCl is added
Answer:
pH is not been modified. No changes.
Explanation:
Our buffer is made of acetic acid, a weak one and the salt from its conjugate base, sodium acetate.
NaC₂H₃O₂ → Na⁺ + C₂H₃O₂⁻
The acetate anion can make hydrolisis in water to produce acetic acid again.
C₂H₃O₂⁻ + H₂O ⇄ C₂H₃O₂H + OH⁻ Kb
KCl is neutral salt. When we dissociate it:
KCl → K⁺ + Cl⁻
Both ions come from a strong base and a strong acid. They won't make hydrolisis in water because they are conjugate weak acid and base
K⁺ + H₂O ← KOH + H⁺
Cl⁻ + H₂O ← HCl + OH⁻
These reactions can't be possible.
That's why it doesn't occur anything in our buffer, this salt does not give OH⁻ or H⁺ to medium to modify pH
What is the new freezing point for a 0.811m solution of Li2O in water?
Answer:
Freezing T° of solution = - 4.52°C
Explanation:
ΔT = Kf . m . i
That's the formula for colligative property about freezing point depression.
Li₂O is an oxide that can not be dissociated but, if we see it's a ionic compound.
Li₂O → 2Li⁺ + O⁻²
3 moles of ions have been formed. Ions dissolved in solution are i, what we call Van't Hoff factor.
m is molality → 0.811 m, this is data
Kf →Cryoscopic constant, for water is 1.86 °C/m
and ΔT = Freezing T° of pure solvent - Freezing T° of solution
We replace: 0°C - Freezing T° of solution = 1.86°C/m . 0.811 m . 3
Freezing T° of solution = - 4.52°C
What would be the temperature change if 3.0 g of water absorbed 15 J of heat? Specific Heat capacity of water= 4.18 J/gºC
Question 19 options:
a
None of the above
b
2.4 ºC
c
1.2 ºC
d
15 ºC
Suppose you will determine the composition of the unknown substance that was collected at the scene of the crime. You are encouraged to work on this case. You can perform a series of tests on the unknown substance and compare results of the same tests performed on known samples. Follow these steps:
List physical properties you can use as a simple method of identifying substances.
Describe how you can use density to help identify unknown substances.
Explain how forensic chemist can help you identify unknown substances.
How important is comparing tests results of know substances in a lab setting?
Answer:
b erergart
Explanation:
PLZZ HELP WILL MARK AS BRAINLIESTTT!!!!!
Answer:
The object is moving with uniform acceleration
Explanation:
Acceleration is defined as the change of speed with time. Hence, we define acceleration as ds/dt.
The slope of a speed/time graph gives us the acceleration of the moving object.
An object is said to move with uniform acceleration when the speed increases by equal amounts in equal time intervals as in the straight line speed/time graph shown in the question
HELP ASAPPPP""""A 0.0200 M NaCl solution was formed when 38.0 grams of NaCl was dissolved in enough water. What was the total volume of the solution formed? (5 points)
32.5 liters
30.3 liters
26.7 liters
22.1 liters
Answer: The volume of the solution formed will be 32.5 L. Explanation: Molarity is defined as the amount of solute present in 1 L of solution. The equation used to determine molarity of the solution follows: We are given: Molarity of the solution = 0.02 mol/L Mass of NaCl = 38 grams Molar mass of NaCl = 58.5 g/mol Putting values in above equation, we get: Hence, the volume of the solution formed will be 32.5 L.
Answer:
32.5
Explanation:
35
Select the correct answer.
Which is true according to the law of conservation of energy?
A.
In a closed system, the total amount of energy in the universe keeps on changing.
B.
The supply of energy is limited, so it is essential to conserve it.
C.
In a closed system, energy can be created and destroyed.
D.
In a closed system, energy cannot be used faster than it is created.
E.
In a closed system, the total energy always remains constant.
Answer:
its a
Explanation:
Which of the following is not a renewable source of energy?
1.) geothermal
2.) coal
3.) solar
4.) wind
2. Coal
It is non renewable energy source.
Answer: the answer would be coal
Explanation: hoped this helped!
Your simulation involved 100 atoms and eight half-life cycles. For half-life cycles 9 and later, how many radioactive nuclei would you expect to be present?
Answer:
you would expect 0 radioactive nuclei to be present
Explanation:
got it right on the assignment
The image below shows the jet stream (darker line) moving across the northern United
States and Canada
Which of the following statements correctly describes how the jet stream effects local
weather?
Answer:
Explanation:
add the statements n will answer w/ 'em thanx
A: Air Pressure south of the jet stream is greater than north of the system
B the jet stream moves storms in to areas with its slow level winds.
C Clear nice weather follow along the the near stream as it winds move eastward
D As the jet stream moves southward, it will bring with it cooler temperatures
ans is d
URGENT: Identify the subatomic particles that determine the atomic number of an element.
Answer:
the number of protons determines the atomic number
Explanation:
Ex. Aluminum has 13 protons, so it's atomic number is 13
hope this helps :)
Dilute hydrochloric acid is gradually added to a solution that is buffered at pH 4.76. How will the pH of the solution be affected?
A. The pH will gradually approach 4.76.
B. The pH will initially remain close to 4.76, then increase quickly when the buffering capacity is exceeded
C. The PH will initially remain close to 4.76 then decrease quickly when the buffer capacity is exceeded
D. The pH will remain close to 4.76 indefinitely
the answer is C.
The PH will initially remain close to 4.76 then decrease quickly when the buffer capacity is exceeded
The acidity or alkalinity of a solution depends upon its hydronium ion concentration and hydroxide ion concentration. The pH will initially remain close to 4.76 then decrease quickly when the buffer capacity is exceeded when dil. HCl is added. The correct option is C.
What is pH?The pH of a solution is defined as the negative logarithm to the base 10 of the value of the hydronium ion concentration in moles per litre. For an acidic solution the pH of the solution is less than 7 and for basic solution the pH is greater than 7.
The pH scale is introduced by the Sorensen is more convenient in expressing the hydronium ion concentration of a solution. The PH will initially remain close to 4.76 then it is suddenly decreases if the buffer capacity is exceeded.
The equation used to calculate the pH is:
pH = -log [H₃O⁺]
Thus the correct option is C.
To know more about pH, visit;
https://brainly.com/question/27945512
#SPJ2
22. Oxidation occurs when materials containing _______________________ are exposed to oxygen and water
Answer:
iron
Explanation:
iron reacts with oxygen easily causing rust to form. the haemoglobin in your red blood cells contains haem which is iron and that's how your body transfers oxygen all over
Isabella is studying the night sky. her teacher gives her an assignment. each night she is to go outside at the same time the observe the stars. on her last night of overreactions, her uncle lets her use his telescope. isabella is surprised at how many more stars she can see through the telescope. Why is it that Isabella can see so many more starts by her uncle's telescope?
Answer:
the telescope is more powerful than the human eye
Answer:
The telescope magnifies the objects and gathers light from them too.
Explanation:
I just did it on USATestPrep
Type the correct answer in the box. Express your answer to three significant figures. Iron(II) chloride and sodium carbonate react to make iron(II) carbonate and sodium chloride: FeCl2(aq) + Na2CO3(s) → FeCO3(s) + 2NaCl(aq). Given 1.24 liters of a 2.00 M solution of iron(II) chloride and unlimited sodium carbonate, how many grams of iron(II) carbonate can the reaction produce? The reaction can produce grams of iron(II) carbonate.
Answer:
The reaction can produce 287 grams of iron(II) carbonate
Explanation:
To solve this question we must find the moles of iron(II) chloride that react. Using the chemical equation we can find the moles of iron(II) carbonate and its mass -Molar mass FeCO3: 115.854g/mol-
Moles FeCl2:
1.24L * (2.00mol / L) = 2.48 moles FeCl2
As 1 mol FeCl2 produce 1 mol FeCO3, the moles of FeCO3 = 2.48 moles
Mass FeCO3:
2.48mol * (115.854g / mol) =
The reaction can produce 287 grams of iron(II) carbonateAnswer:
287
Explanation:
There are 50grams of Cl2 how many molecules are produced for Cl2?
Explanation:
cl2 = 50/71
mole of cl2 = 0.704
no.of molecules = mole × avagadro no.
no of molecules = 0.704× 6.022×10²³
no. of molecules = 4.23×10²³
A student finds that the water's temperature went from 18oC to 38oC. Calculate how many calories are in the peanut.
Answer:
567 calories.
Explanation:
There 567 calories in 100 grams of peanut. In 100 grams of peanut, 49 gram is the fat, 26 grams of protein, 16 grams of carbohydrates, Sodium is 18 mg, Potassium is 705 mg. Calcium is present in peanut about 9%, Iron is 25% , Vitamin B-6 is 15% and Magnesium is 42% of their total weight. Oil content is high in the Peanut so this is the reason for high calories in peanut. It is a good source of proteins and potassium.
URGENT! What occurs during a chemical reaction. :)
A.) Atoms of two or more elements are destroyed.
B.) Atoms of two or more elements oppose one another.
C.) Atoms of two or more elements bond together.
D.) Atoms of two or more elements trade protons.
10. Stronger IMFs (intermolecular forces) lead to... ?
1.higher MP and BP
2. unique coloration of compounds
3.lower MP and BP
4. weird names of compounds
Which of the following best explains the relationship between peak to peak amplitude and semi amplitude
Answer:
Which of the following best explains the relationship between peak-to-peak amplitude and semi-amplitude? Semi-amplitude is half the distance of the peak-to-peak amplitude. Semi-amplitude is the same distance as the peak-to-peak amplitude.
Choose ALL
BIOTIC factors
Lesson 5.01
Question 1 options:
protists
animals
fungi
plants
salinity
Answer:
protists
animals
fungi
plants
Explanation:
i took the test let me know if im wrong tho
The biotic factors from the following options are protist, animals, fungi, and plants. Options A, B, c, and D are correct.
What are biotic factors?Biotic factors are those factors which can grow, and reproduce themselves.
Plants, animals, protists, and fungi are biotic factors that live, eat ad reproduce.
Salinity is the quality of any solution. It is not a biotic factor.
Thus, the correct options are A, B, c, and D.
Learn more about biotic factors
https://brainly.com/question/27430655
#SPJ2
which of the following examples where molecules are slightly far apart
A.rock
B.water
C.smoke
D.plasma ball
Answer:
in my opinion I think is D you don't have to choose it
Question 26 (3 points)
In the lab, a cube of wood has a mass of 41.2 grams and its temperature rises from
28.1°C to 65.1°C when placed outside in the sun for a period of time. Calculate the
amount of heat absorbed by the wood. The specific heat of wood is 1.76 J/g°C.
6
Round your answer to 1 decimal place.
Your Answer:
1
Answer
units
D Add attachments to support your work
Question 27 (3 points)
Answer:
2682.9J is the heat absorbed by the wood
Explanation:
To find the heat absorbed for a material we must use the equation:
Q = S*m*ΔT
Where Q is heat absorbed in Joules
S is specific heat of the material = 1.76J/g°C for wood
m is the mass of the material = 41.2g
ΔT is change in temperature = 65.1°C - 28.1°C = 37.0°C
Replacing:
Q = 1.76J/g°C*41.2g*37.0°C
Q = 2682.9J is the heat absorbed by the wood