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A Heat Pack is An Example Of A Endothermic Process.
An Endothermic Reaction Is A Reaction That Requires Energy To Move Forward.
An endothermic process is D. a cold pack, cooling.
Explanation:Endothermic reaction is that type of chemical reaction that requires heat from the surrounding for the reaction to occur. It basically draws heat from the environment to imitate the reaction. The process of using a cool pack for cooling is also an example of endothermic reaction as the heat is absorbed from the surrounding object by the cool pack.
Due to this heat, the ice in the cool pack begins to melt. This process is considered endothermic because the physical change in state of ice into water is not possible without the heat from the surrounding.
The combustion of methane, CH4, releases 890.4
kJ/mol. That is, when one mole of methane is burned,
890.4 kJ are given off to the surroundings. This means
that the products have 890.4 kJ less than the reactants.
Thus, AH for the reaction = - 890.4 kJ. A negative symbol
forAH indicates an exothermic reaction.
CH (g) + 20 (g)> CO2 (g) + 2 H0 (1); AH = - 890.4 kg
a) How much energy is given off when 2.00 mol of CH,
are burned?
b) How much energy is released when 22.4g of CH. are
burned?
Answer:
[tex]\boxed{\text{a) 1.78 MJ; b) 1.25 MJ}}[/tex]
Explanation:
[tex]\rm CH$_4$ + 2O$_2 \longrightarrow \,$ CO$_2$ + 2H$_2$O; \Delta H = - 890.4 \text{ kJ}$\cdot$\text{mol}$^{-1}$[/tex]
a) Energy from 1 mol
[tex]\Delta_{\text{c}}H^{\circ} = \text{2.00 mol} \times \dfrac{\text{-890.4 kJ}}{\text{1 mol}}=\text{-1780 kJ} = \textbf{-1.78 MJ}\\\\\text{The reaction gives off } \boxed{\textbf{1.78 MJ}}[/tex]
b) Energy from 22.4 g
(i) Convert grams to moles
[tex]n = \text{22.4 g } \times \dfrac{\text{1 mol }}{\text{16.04 g}} = \text{1.399 mol}[/tex]
(ii) Convert moles to energy
[tex]\Delta_{\text{c}}H^{\circ} = \text{1.399 mol} \times \dfrac{\text{-890.4 kJ}}{\text{1 mol}}=\text{-1250 kJ} = \textbf{-1.25 MJ}\\\\\text{The reaction releases } \boxed{\textbf{1.25 MJ}}[/tex]
what is the wavelength of a wave with a velocity of 50 m/s and a frequency of 5Hz
A 250 m
B 0.1 m
C 10m
D 0.01 m
Answer:
C. 10 m
Explanation:
The speed of a wave v = λf where λ is the wavelength and f the frequency of the wave.
Making λ the subject of the formula we get
λ= v/f
f= 5 Hz
v= 50 m/s
λ= 50 m/s÷ 5 Hz
=10 meters
Answer:
C. 10 Meters
Explanation:
A P E X
If a greyhound can run with an average velocity of 60 km/h, how far can it
travel in 30 seconds?
Answer: 0.5 klms
Explanation:
Hope it helped :))
6. Which of the following statements correctly describes what happens to the diaphragm during an
inhalation, when the lungs inflate?
O A. The diaphragm returns to its resting state.
O B. The diaphragm contracts and flattens.
O C. The diaphragm only moves during exhale.
O D. The diaphragm expands.
Answer:
O B. The diaphragm contracts and flattens.
Explanation:
The diaphragm is a skeletal striated muscle that separates the abdominal cavity from the thoracic cavity, has a dome shape and plays a key role in breathing. Locate near the lumbar vertebrae, the lower ribs and the sternum and can be divided according to its location into three parts: sternal, costal and lumbar.
During inhalation, the diaphragm contracts and flattens, reducing the pressure inside the chest and compressing the viscera of the abdomen, which facilitates the entry of air into the lungs.
At the expiration, the inverse process occurs: it relaxes and rises, increasing the pressure inside the chest and expelling air from the lungs.
NEED ANSWER ASAP According to Ohm’s law, resistance is equal to voltage divided by
current.
conduction.
potential.
time.
Answer:
A
Explanation:
Ohm's law is stated as E = current * resistance (E = I * R)
When you rearrange the formula, you get R = E/I
The answer is current -- A
Answer:
a
Explanation:
An acid is a substance that donates protons.
true or false please answer asap!!!
Answer:
The correct answer is True.
Explanation:
An acid is a molecule that has the property of donating a proton or accepting a pair of electrons during a reaction.
The strength of an acid is related to their tendency to lose a proton. A strong acid is one that separates all its components when it comes into contact with water.
As its composition includes hydrogen ions, the more its concentration, the higher the acidity will be, and the lower the pH of the solution.
Its main characteristic is that on contact with water they produce a sour taste.
An acid is a substance that donates protons. Therefore, this given statement is very true.
Acid is any material that when dissolved in water has a sour taste, alters the colour of some indicators (blue litmus paper turns red, for example), combines with some metals (like iron) to release hydrogen, reacts chemically bases to produce salts, and catalyses various chemical reactions. Acids are examples of both organic chemicals that belong to the acid group, carboxylic acid, sulfonic acids, or phenol groups as well as the inorganic substances that comprise the mineral acids, such as sulfuric, nitric, hydrochloric, etc phosphoric acids. An acid is a substance that donates protons. Therefore, this given statement is very true.
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What is the result of multiplying (2.5 × 1010) × (2.0 × 10-7)?
A. 5.0 × 103
B. 5.0 × 10-3
C. 5.0 × 1017
D. 5.0 × 10-17
Answer: The correct option is,
A. [tex]5.0\times 10^3[/tex]
Explanation:
Given expression,
[tex](2.5\times 10^{10})\times (2.0\times 10^{-7})[/tex]
[tex]=2.5\times 2.0\times 10^{10-7}[/tex]
( By using product property of exponent i.e. [tex]a^m\times a^n = a^{m+n}[/tex] )
[tex]=5.0\times 10^3[/tex]
Therefore,
OPTION A is correct.
14. What are the products of the oxidation of glucose?
Answer:
carbon dioxide and water
Explanation:
Answer:
carbon dioxide and water
Explanation:
the molecules represent the products of thorough energy extraction
Which type of graph would best to represent a budget?
Answer:
Line or a bar graph
Explanation:
Answer:
I'm pretty sure it's the pie chart
Explanation:
8. What happens to matter during a chemical reaction
Answer: A new substance(product) is made from different elements(reactants) joined by chemical bonds
Explanation: To have a chemical reaction the chemical properties must change. Atoms are never created or destroyed during chemical reaction but at least one chemical bond is broken or formed. Evidence of a chemical change include: change of odor, change of color (for example, silver to reddish-brown when iron rusts), and change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat.
what tool did Maurice use when studying dna???
Answer:
He used the X-ray tool
Explanation:
Answer:
a x ray
Explanation: mark me brainliest plzzz
Calculate number of CO2 molecules in 0.250 mol of co2
This calculation yields 1.506 × 10²³ molecules of CO₂.
Calculating the Number of CO₂ Molecules in 0.250 mol of CO₂
To determine the number of CO₂ molecules in 0.250 mol of CO₂, we can use Avogadro's number, which is the number of particles (atoms, molecules, ions, etc.) in one mole of a substance.
Step-by-Step Explanation:
Avogadro's number is 6.022 × 10²³ molecules/mol.
We are given 0.250 mol of CO₂.
Multiply the number of moles by Avogadro's number to find the number of molecules:
Calculation:
0.250 mol × 6.022 × 10²³ molecules/mol
= 1.506 × 10²³ molecules
Therefore, there are 1.506 × 10²³ molecules of CO₂ in 0.250 mol of CO₂.
Having food in the stomach __________ the rate at which a person's BAL rises.
Answer:
Explanation:
It rises Food in your stomach (Food slows down alcohol absorption. What's the best to eat? Protein! It takes the longest to digest)
It will slow down the rate at which a person's BAL rises.
11) If 352 moles of butane (CH) is mixed with 8.47 moles of oxygen gas, how many grams of water will be produced?
2C,H,0 + 130, 800, + 10 H,0 (balanced)
Answer:
117 g
Explanation:
We are given the amounts of two reactants, so this is a limiting reactant problem.
1. We know we will need an equation with masses and molar masses, so let’s gather all the information in one place.
M_r: 63.55 32.00 18.02
2C₄H₁₀ + 13O₂ ⟶ 8CO₂ + 10H₂O
n/mol: 352 8.47
2. Calculate the amount of water that each reactant can produce
(a) From C₄H₁₀
Moles of H₂O = 352 mol C₄H₁₀ × (10 mol H₂O/2 mol C₄H₁₀) = 704 mol H₂O
(b) From O₂:
Moles of H₂O = 8.47 mol O₂ × (10 mol H₂O/13 mol O₂) = 6.515 mol H₂O
3. Identify the limiting reactant
The limiting reactant is O₂, because it gives fewer moles of H₂O.
4. Calculate the mass of water
Mass of H₂ = 5.515 mol H₂O × (18.02 g H₂)/(1 mol H₂O) = 117 g H₂O
The reaction produces 117 g H₂O.
Which of the following hydrocarbons will most likely be found around cows? A. ethane B. methane C. octane D. decane
Answer:B
Explanation:I know for a fact Its BAnswer:
Methane
Choice B is correct
Explanation:
Methane is a key byproduct of the bacterial breakdown in the gut.
Therefore, Methane is most likely to be found around cows
what is the primary purpose of a rate law
Answer:
The rate law or rate equation for a chemical reaction is an equation that links the reaction rate with the concentrations or pressures of the reactants and constant parameters. For many reactions the rate is given by a power law such as.
Explanation:
The other person Goggled it. So, pick me as Brainliest.
The primary purpose of a rate law is to provide a mathematical framework that links the rate of a chemical reaction to the concentration of its reactants.
The primary purpose of a rate law is to provide a mathematical expression that describes the relationship between the rate of a chemical reaction and the concentration of its reactants. Through rate laws, scientists can calculate expected yields, determine optimum conditions for economic chemical processes, and understand the course of individual reactions. The derivation of rate laws is essential as they are not directly obtained from chemical equations for ordinary reactions but rather determined from experimental data involving the measurement of concentrations over time.
To ascertain a rate law, the method of initial rates is commonly employed. This involves conducting experiments under varying reactant concentrations and measuring the reaction rates to deduce the reaction order and rate constant. These parameters are indispensable for formulating a rate law, which in turn allows for the calculation of reaction rates under different conditions and aids in the identification of the reaction mechanism.
How will the rate at which a solid solute dissolves change if the solution is stirred?
The rate at which the solute dissolves will stay the same.
The rate at which the solute dissolves will increase.
The rate at which the solute dissolves will decrease.
The rate at which the solute dissolves will fluctuate.
Answer:
The rate at which the solute dissolves will increase.
Explanation:
If a solution is stirred, the rate at which a solute dissolves would increase substantially provided the solution is not yet saturated.
Stiring would cause more of the solution to come in contact with every part of the solute. It will increase the surface area of contact for the solution to act which will shoot up the rate of reaction. Stiring helps to bring solutes in solutions into a more close contact with the molecules or compounds of the medium.
Match the name of the following compound:
MgSO4 · H2O
Magnesium sulfate monohydrate
Magnesium (II) sulfate monohydrate
Magnesium (II) sulfate hydrate
Magnesium sulfate hydrate
Answer:
number 2 is the answer my friend said
Explanation:
Answer:
Magnesium sulfate monohydrate
Explanation:
The compound is a salt, we have a metal connected to an ion.
To name a salt, first of all, we put the name of the cation, which is the first elemental in the compound. It is followed by the name of the anion.
In this case, the cation is the Magnesium and the anion is the anion sulfate. When the cation can have more than one oxidation number, we need to put this number in parenthesis, like this:
Iron (II) sulfate (FeSO4)
Iron (III) sulfate (Fe2(SO4)3)
However, magnesium can only have 2 as oxidation number, because it's from family 2 in the periodic table. So it's unnecessary to put this information.
As the salt has water in its structure, it's a hydrated salt, and this information needed to be in its name. Because it has only one molecule of water, we put the name monohydrate.
Which is the most likely way an automotive engineer would use chemistry
Final answer:
An automotive engineer would most likely use chemistry to design and improve automobile catalytic converters, ensuring efficient combustion and reduced toxic emissions. They also work on reformulating gasoline to meet environmental standards and improve engine performance.
Explanation:
The most likely way an automotive engineer would use chemistry is through the design and development of automobile catalytic converters. Scientists have engineered catalytic converters to significantly reduce the toxic emissions resulting from gasoline burned in internal combustion engines. By implementing a blend of catalytically active metals, these converters facilitate the complete combustion of carbon-containing compounds into carbon dioxide, while also diminishing the output of nitrogen oxides.
Another aspect of chemistry in automotive engineering involves the reformulation of gasoline. Removing substances like tetraethyllead, which hampers exhaust catalysts, and decreasing the presence of highly volatile and unsaturated hydrocarbons are critical to reduce photochemical smog and increase engine efficiency.
2H2O2 → 2H2O + O2 synthesis decomposition combustion
Answer:
Decomposition
Explanation:
The equation 2 H₂O₂ → 2 H₂O + O₂ is an example of a decomposition reaction. During decomposition, a compound breaks down into two or more products under the favorable conditions, without combining with other reagents.
However, the reaction can be catalyzed using a suitable catalyst.
Which sentence from Holes contains an implied personality trait?
Stanley and his parents had tried to pretend that he was just going away to camp for a while, just like rich kids do.
He'd just been in the wrong place at the wrong time.
Stanley felt somewhat dazed as the guard unlocked his handcuffs and led him off the bus.
Stanley nodded to show he understood
Stanley and his parents had tried to pretend that he was just going away like rich kids do ( A ) is an implied personality trait
Although the excerpt from Holes is missing from your question an answer is provided based on the principle of implied personality trait
An implied personality trait is used to describe the character of a person based on his actions and thought. also implied personality trait are used to make inferences about an individual.
As seen in the sentence " Stanley and his parents had tried to pretend that he was just going away like rich kids do " the inference /conclusion contained in this sentence is that Stanley and his parents are pretending
Hence we can conclude that ; Stanley and his parents had tried to pretend that he was just going away like rich kids do ( A ) is an implied personality trait
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19 grams of sodium and 34 grams of chlorine are measured out and put into separate glass vials that weigh 10 grams each. Then sodium is dumped into the glass vial containing the chlorine. They react and form a crystalline solid. What is the total weight of the glass vial containing the final product?
Answer:
63.02 g.
Explanation:
Na reacts with Cl₂ according to the balanced equation:2Na + Cl₂ → 2NaCl,
It is clear that 2 mole of Na react with 1 mole of Cl₂ to produce 2 moles of NaCl.
Firstly, we need to calculate the no. of moles of Na and Cl₂:no. of moles of Na = (mass/atomic mass) = (19.0 g/22.9897 g/mol) = 0.826 g.
no. of moles of Cl₂ = (mass/atomic mass) = (34.0 g/70.906 g/mol) = 0.48 g.
From the stichiometry, Na reacts with Cl₂ with a molar ratio (2:1).
So, 0.826 mol of Na "the limiting reactant" reacts completely with 0.413 mol of Cl₂ "left over reactant".
The no. of moles of Cl₂ remained after the reaction = 0.48 mol - 0.413 mol = 0.067 mol.
∴ The mass of Cl₂ remained after the reaction = (no. of moles of Cl₂ remained after the reaction)(molar mass of Cl₂) = (0.067 mol)(70.906 g/mol) = 4.75 g.
To get the no. of grams of produced NaCl:using cross multiplication:
2 mol of Na produce → 2 mol of NaCl, from the stichiometry.
∴ 0.826 mol of Na produce → 0.826 mol of NaCl.
∴ The mass of NaCl produced after the reaction = (no. of moles of NaCl)(molar mass of NaCl) = (0.826 mol)(58.44 g/mol) = 48.27 g.
∴ The total weight of the glass vial containing the final product = the weight of the glass vial + the weight of the remaining Cl₂ + the weight of the produced NaCl = 10.0 g + 4.75 g + 48.27 g = 63.02 g.
Answer:
63g
Explanation:
You don't have to make a lot of calculus to find the answer.
Just only remember the principle of the matter who says
"The matter is not created or destroyed only transformed"
It means, that even when you are transforming sodium and chlorine to obtain sodium chlorine, who is the crystalline solid, you can't obtain more matters (grams) that you put at the beginning of the experiment.
As well, you just have to add the grams of the sodium, chlorine and the recipient, glass vial containing the final product, as follow:
19 grams of sodium + 34 grams of chlorine + 10 grams glass vial
19 + 34 + 10 = 29 + 34 = 63 g
remember, the matter isn't create, just transformed, so, you can't add any more grams that you already have.
A substance added in The final stages to remove sulphur from coal is
A substance used to remove Sulphur from coal is a desulfurizing agent, commonly a limestone slurry. It chemically reacts with the Sulphur emissions, creating less harmful substances like Gypsum.
Explanation:A substance used in the final stages to remove Sulphur from coal is called a desulfurizing agent or a scrubber. One technique includes the use of a limestone slurry, which reacts chemically with the sulphur emissions and converts them into less harmful substances, such as gypsum. Gypsum, or calcium sulfate, is a beneficial byproduct because it can be used in the manufacture of wallboard and other building materials. Thus, the process not only removes pollutants like sulfur from the coal but also creates a valuable byproduct.
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Which of the following represents the ester functional group?
A. -COO-
B. -CHO
C. -COOH
D. C=O
Answer:
D. C=O
Explanation:
Esters are formed by the condensation of alcohols and acids with minus water. During the reaction, at least one -OH group is replaced by an O- alkyl group. The resulting compound is an ester and has a characteristic fruity smell. Its functional group is C=O
Answer: A. -COO-
Explanation:
Functional groups are specific group of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.
A. Esters have functional group [tex]-O=C-OR[/tex].
Example: methyl ethanoate with molecular formula [tex]CH_3COOCH_3[/tex]
B. Aledydes have functional group [tex]-O=CH[/tex].
Example: Ethanal with molecular formula [tex]CH_3CHO[/tex]
C. Acids have functional group [tex]-O=C-OH[/tex].
Example: Ethanoic acid with molecular formula [tex]CH_3COOH[/tex]
D. Ketones have functional group [tex]-C=O[/tex].
Example: Propanone with molecular formula [tex]CH_3COCH_3[/tex]
A circle is centered at the point (5, -4) and passes through the point (-3, 2). The equation of this circle is (x + )2 + (y + )2 = . Reset
Answer:
[tex](x-5)^{2}+(y+4)^{2}=100[/tex]
Explanation:
We have been given the center of the circle as (5, -4) and a point on the circumference as (-3, 2). We first determine the radius of the circle. The radius is the distance from the center to any point on the circumference. Using the distance formula, we have;
[tex]radius=\sqrt{(5--3)^{2}+(-4-2)^{2}}\\radius=\sqrt{64+36}=10[/tex]
The radius of the circle is thus 10 units.
The equation of a circle with center (a,b) and radius r units is given as;
[tex](x-a)^{2}+(y-b)^{2}=r^{2}[/tex]
Plugging in the values given we have;
[tex](x-5)^{2}+(y+4)^{2}=100[/tex]
Is so2 a formula unit
Answer:
The molecular formula for Sulfur Dioxide is SO2. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Sulfur Dioxide, or 64.0638 grams.
So yes it is a unit
Explanation:
what are the 4 phases of matter in order of increasing engery content?
Answer:
plasma,gas, liquid, solid
Explanation:
Plasmas are hotter than gases and so have more kinetic energy, next is gas, then liquid and finally a solid.
Answer:
the four phrase are plasma, liquid , gas , and solid
Explanation:
Identify which properties could correspond to solids, plasmas, or both.
maintain a unique shape.
____particles collide infrequently with other particles.
____particles have very high velocities.
____can conduct electricity.
____contain protons.
____typically have a low temperature.
____structure has long-range order.
Explanation:
Plasma is defined as the state of matter which is a hot ionized gas that consists of positively charged ions and negatively charged electrons.
Like gases, particles of a plasma are also held by weak forces that are Vander waal forces. And, as it is a hot ionized gas therefore, particles of plasma move rapidly from one place to another.
In a solid, molecules are held together by strong intermolecular forces of attraction. As a result, they are unable to move from their initial place but they can vibrate at their mean position.
Hence, in solid substances the molecules have low kinetic energy. Also, molecules in a solid are placed in a long range order.
Solids like copper, silver etc able to conduct electricity.
Also, both plasma and solids contain proton because every atom contains neutrons, protons and electrons.
Thus, we identify the properties corresponding to solids, plasmas, or both are as follows.
Solids maintain a unique shape.Plasma particles collide infrequently with other particles.Plasma particles have very high velocities.Both can conduct electricity.Both contain protons.Solids typically have a low temperature.Solids structure has long-range order.Answer:
Identify which properties could correspond to solids, plasmas, or both.
Solids
maintain a unique shape.
Plasma
particles collide infrequently with other particles.
Plasma
particles have very high velocities.
Both solids and plasmas
can conduct electricity.
Both solids and plasmas
contain protons.
Solids
typically have a low temperature.
Solid
structure has long-range order.
Explanation:
Which of the following is a testable hypothesis?
A. If I brush my teeth, I will get fewer cavities than if I don't brush my
teeth.
B. Green toothpaste tastes better than blue toothpaste or red
toothpaste.
C. Smart, careful, healthy people always brush their teeth.
D. It's wrong to not brush your teeth before you have an important
conversation with someone.
Answer:
If I brush my teeth, I will get fewer cavities than if I don't brush my teeth.
Explanation:
apex
hat is the best way to compare a concentrated solution to a dilute solution, given the same volume of solution?
Answer:
Using the molarity of the solution
Explanation:
The concentration of the two solutions can be compared by the use of the number of moles of solute present in each of the solutions. The solution with a higher molarity will be concentrated while the solution with a lower molarity will be dilute.
To compare concentrated and dilute solutions, one looks at the amount of solute in relation to the solvent for the same volume. Calculation of the new concentration after dilution can use the [tex]M_1 \times V_1 = M_2 \times V_2[/tex] equation, applying to stock solutions to reach desired dilutions.
To compare a concentrated solution to a dilute solution while maintaining the same volume, one should examine the ratio of solute to solvent present in the solution. A concentrated solution has a higher concentration of solute, meaning there is a large amount of solute relative to the solvent.
On the other hand, a dilute solution contains a smaller amount of solute hence a lower concentration. This concept can be analogous to the process of making juice from concentrate; you add water to the concentrated juice, thereby increasing the volume while reducing the solute-to-solvent ratio.
When performing calculations, you can use the dilution equation [tex]M_1 \times V_1 = M_2 \times V_2[/tex], where M represents molarity and V represents volume, to determine the new concentration after dilution. For instance, if you have 100 mL of a 2.0 M HCl and dilute it to 500 mL, you can calculate the new molarity ([tex]M_2[/tex]) by applying this equation.
The methodology of dilution typically involves taking a measured volume of a stock solution and adding solvent to reach the desired concentration. This process of diluting adjusts the ratio of solute to solvent, creating a solution of lesser concentration.