Answer: d
Explanation:
took the test
What does the A Hof a reaction represent?
A. It represents the heat involved in a reaction.
B. It represents the thermal energy in a system.
C.
represents the randomness of the products.
D. It represents the usable energy in a reaction.
egation.
Answer:
it represents the heat involved in a reaction
Explanation:
just took the test
The delta H of a reaction represents the heat involved in a chemical change .
What is a chemical change?
Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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In this chemical equation which of the following identifies the reactant(s)?
Answer:
2na+o2
Pls mark as brainliest
Answer:
A
Explanation:
2NA + 02
These are your reactants, which are always on the left side of the chemical equation.
hope this helped mark brainliest pls xx
I NEED HELP ! ANYTHING WILL HELP!
Why are there few fossils
of sea slugs?
Why are you more likely to find a fossilized trilobite than a fossilized sea urchin?
How is a calorimeter used in this experiment different from the ones used to find the energy content of a snack
Answer:
Kindly check the explanation section.
Explanation:
PS: Note that enough information are not being provided and we do not know the experiment this question is all about. However, some information are provided below which is going to aid in solving when you get access to the main question.
The determination of the heat transferred from one substance to another is one of the important aspect in science. The method in which this heat is being measured is known as calorimetry and the instrument used in this technique is known as the calorimeter.
When the energy content of a snack is needed to be calculated, there is the need use a type of instrument known as bomb calorimeter.
Most of the calorimeters used by students are not so expensive like the used in the industries. Most of these calorimeters operates at a constant pressure while the Bomb Calorimeter operates at constant volume.
What is a mole of something? Why do scientists use the concept of a mole?
Answer: A mole is a chemical unit to measure mass of substance.
Explanation:
A mole can be defined as 6.02214076 × 1023 of atoms, ions, molecules and others. A mole is the total amount of discrete entity within a substance present in the form of atoms, ions, and molecules. As atoms, ions, molecules are small entities within any substance so it is necessary to measure each of them and recognize them so the scientists development the concept of mole. It is the convenient unit of measurement because of the presence of greater number of molecules, atoms, and ions present in any substance.
Answer:
The mole is an SI unit used to measure the amount of any substance. One mole is exactly 6.02214076×10 23 particles.
Explanation:
The concept of the mole is important for scientists because it means that one mole of any element has exactly the same number of atoms as one mole of any other element. This information allows chemists to count atomic particles for even very complex chemistry formulas and reactions.
Chlorine and hydrogen gas react to form hydrogen chloride as shown in the following reaction: Cl 2 (g)+H 2 (g) 2HCl (g) If a 48.5 L sample of chlorine gas was reacted with excess hydrogen at 450 K and 1.20 atm , how many grams of hydrogen chloride is produced ?
It’s 1.58 moles
Answer:
H
Explanation:
Approximately 1229.80 grams of hydrogen chloride (HCl) is produced.
We must use the specified number of moles of the limiting reactant, in this case chlorine gas [tex](Cl_2)[/tex], to calculate the mass of hydrogen chloride (HCl) produced during the reaction. We can see from the balanced equation that 1 mole of [tex]Cl_2[/tex] results in the formation of 2 moles of HCl.
Given:
Volume of Cl2 gas = 48.5 L
Temperature (T) = 450 K
Pressure (P) = 1.20 atm
Moles of Cl2 = 1.58 moles
The ideal gas law equation can be used to calculate the amount of HCl produced:
PV = nRT
Where:
P = pressure
V = volume
n = moles
R = ideal gas constant
T = temperature
First, we must use the ideal gas law equation to obtain the amount of HCl in moles:
n(HCl) = (P * V) / (R * T)
Using the known values:
P = 1.20 atmV = 48.5 LR = 0.0821 L·atm/(K·mol)T = 450 Kn(HCl) = (1.20 atm * 48.5 L) / (0.0821 L·atm/(K·mol) * 450 K)
≈ 33.73 moles
To the nearest two decimal places, the mass of HCl is equal to its molar mass times its molar mass, or 33.73 mol times 36.46 g/mol, or 1229.80 g.
Mass of HCl = moles of HCl * molar mass of HCl
= 33.73 moles * 36.46 g/mol
≈ 1229.80 grams (rounded to two decimal places)
Therefore, approximately 1229.80 grams of hydrogen chloride (HCl) is produced.
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I need c and d pleaseeee!!
Answer: yes
Explanation: cuz i know lol
please help people! science science! thank you!
Answer:
A. Is your answer
All the other ones are not valid because they are lower to the ground and you wouldn't have enough MOMENTUM to put you up for the top of the star.
Hope this helps!
The balanced net ionic equation for precipitation of CaCO3 when aqueous solutions of Li2CO3 and CaCl2 are mixed is
Answer:
Li2CO3+CaCl2=CaCO3+LiCl
Oleic acid's melting point is 14°C and it's boiling point is 360°С. What phase is this substance
at room temperature 25°C?*
A. Solid
B. Liquid
C. Gas
D. Impossible to tell
A student asks why the ashes from a fire have much lower mass than the wood that was burned. Which of the following is the correct answer to the student's question?
Answer:
It have lower mass because much of the ashes came from the burned wood. (ashes were like little parts of the wood). plus most of the fuel was turned in to fire (light and heat energy) so yeah ash is just the left over.
Explanation:
Extreme dryness is a characteristic of the____.
grasslands
desert
tropical rainforest
Answer:
desert
Explanation:
rainforest include a lot of rain, and grasslands have grass. grass includes water and sunlight. which leaves you to desert
The graphic represents the Milky Way galaxy.
Which label best represents the location of our solar system within the milky way galaxy?
A
B
C
D
Answer:
planets,meteoroids and asteroids
Explanation:
Sodium chloride, NaCl, can be used to melt snow. How many moles of sodium chloride are in a 10 kg bag?
Answer:
171 moles of sodium chloride
Explanation:
Number of moles = mass/molar mass
Molar mass of sodium chloride = 58.5 g/mol
mass of sodium chloride = 10 Kg or 10,000 g
Now, to obtain the number of moles of sodium chloride;
Number of moles = 10,000 g/58.5 g/mol
Number of moles = 171 moles of sodium chloride
When no more solute can dissolve a solution is described as...
Answer:
Saturated solution
Explanation:
When is no more solute can be added then it is saturated solution
what is the percent composition of potassium phosphate? show your work
Answer:
35.62%
Mass percent composition of K = 0.3562 x 100% Mass percent composition of K = 35.62%
Explanation:
Why do organic materials decompose so slowly inside of a landfill? List 3 factorsthat are required for biodegradation
Answer:
The more organic waste present in a landfill, the more landfill gas is produced by bacterial decomposition. Some types of organic waste contain nutrients, such as sodium, potassium, calcium, and magnesium, that help bacteria thrive. When these nutrients are present, landfill
Explanation:
6. Choose a pair of words to make the statement correct. Energy transfers from
substances to ___substances.
A. cold to hot
B. hot to cold
C. hot to hot
D. cold to cold
Answer:
B. hot to cold
Explanation:
Energy wants to reach thermal equilibrium (which is basically just balanced temperature) so it will move from hot to cold to make the cold object warmer and the hot object cooler.
How many mole are in 14.5 grams of neon please explain
Answer:
0.725 moles
Explanation:
Use the mole = mass/mr equation to find the moles.
Mole = 14.5/20 (Neon's Mr) = 0.725 Moles
More bushes of potatoes will be produced if the soil is fertilized more WHAT IS THE INDEPENDENT VAIRABLE AND THE DEPENDENT VARIABLE
Answer:
The dependent variable is the bushes of potatoes while the soil is an independent variable.
Explanation:
An experiment can be defined as an investigation which typically involves the process of manipulating an independent variable (the cause) in order to be able to determine or measure the dependent variable (the effect).
This ultimately implies that, an experiment can be used by scientists to show or demonstrate how a condition causes or gives rise to another i.e cause and effect, influence, behavior, etc in a sample.
Cause and effect can be defined as the relationship between two things or events in which an occurrence one (cause) leads to the occurrence of another (effect).
In an experiment , the variable being manipulated by an experimenter is known as an independent variable while the dependent variable is the event expected to change when the independent variable is manipulated.
Hence, the dependent variable is the bushes of potatoes while the soil is an independent variable.
type of ions do acids give off? hydroniumm hydrogen heliumhy dronium and hydrogen
Answer:
Substances that give H + 1 ion when dissolved in water are called acids
Explanation:
How do trends in the periodic table help predict the properties of an element
Sulfuric acid reacts with aluminum hydroxide by double replacement producing aluminum sulfate and water Write chemical reaction. If 30 g of sulfuric acid reacts with 25 g of aluminum hydroxide, identify the limiting reactant?
Answer: [tex]H_2SO_4[/tex] is the limiting reagent.
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
The balanced chemical equation is:
[tex]3H_2SO_4(aq)+2Al(OH)_3(aq)\rightarrow Al_2(SO_4)_3(aq)+6H_2O(l)[/tex]
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} H_2SO_4 =\frac{30g}{98g/mol}=0.31moles[/tex]
[tex]\text{Moles of} Al(OH)_3=\frac{25g}{78g/mol}=0.32moles[/tex]
According to stoichiometry :
3 moles of [tex]H_2SO_4[/tex] require = 2 moles of [tex]Al(OH)_3[/tex]
Thus 0.31 moles of [tex]H_2SO_4[/tex] will require=[tex]\frac{2}{3}\times 0.31=0.21moles[/tex] of [tex]Al(OH)_3[/tex]
Thus [tex]H_2SO_4[/tex] is the limiting reagent as it limits the formation of product and [tex]Al(OH)_3[/tex] is the excess reagent.
True or Flase: dissolving salt in distilled water creates a homogeneous mixture.
Answer:
true
Explanation:
Answer:
true
Explanation:
because the dissolved salt is evenly distributed throughout
if life had existed during thie won the fossils probably would not have survived because
Answer:
because life would have use fossil for their benefits.
what caused light to appear bent when it refracts ?
Answer:
Light refracts whenever it travels at an angle into a substance with a different refractive index (optical density). This change of direction is caused by a change in speed. ... When light enters a more dense substance (higher refractive index), it 'bends' more towards the normal line.
please help i genuinely don’t know what to do
Which of the following is true of reproduction?
Answer:
none
Explanation:
Answer:
None of them?
Explanation:
what are the physical and chemical properties of acids? please specify which is which
what are the physical and chemical properties of bases?
Answer: Acids are chemical substances which are characterized by a sour taste in an aqueous medium. They have the tendency to turn blue litmus red. On the other hand, bases are chemical substances which are characterized by a bitter taste and are slippery to the touch. Some bases are soluble in water while others are not. Acids give off H+ (Hydrogen) ions in water; bases give off OH- (Hydroxide) ions in water. Acids generally taste sour due to the sour H+ ion; bases taste bitter due to the OH- ion; but they may have other tastes depending on the other part of the molecule. Bases are usually soapy in nature.
Explanation: Acids
Aqueous solutions of acids are electrolytes, meaning that they conduct electrical current. ...
Acids have a sour taste. ...
Acids change the color of certain acid-base indicates. ...
Acids react with active metals to yield hydrogen gas. ...
Acids react with bases to produce a salt compound and water.
Acids taste sour, conduct electricity when dissolved in water, and react with metals to produce hydrogen gas. Certain indicator compounds, such as litmus, can be used to detect acids. Acids turn blue litmus paper red. The strength of acids is measured on the pH scale.
Which equation is balanced?
A. H 2 + O 2 → H 2O
B. 2Na + Cl 2 → 2NaCl
C. KClO 3 → KCl 2 + 3O 2
D. CH 4 + 2O 2 → CO 2 + H 2 O