Answer:
where are the statements??
The positive sign of the energy difference in a chemical reaction would indicate that ..........
A) the chemicals are losing energy to the surroundings.
B) the chemicals are gaining energy from the surroundings.
Answer:
B) the chemicals are gaining energy from the surroundings.
Explanation:
The positive sign of the energy difference in a chemical reaction would indicate that the chemicals are gaining energy from the surroundings. This is what happens in an endothermic reaction.
In an endothermic reaction, heat is absorbed from the surroundings hence the surrounding becomes colder at the end of the changes.
Here the energy change is assigned a positive value. This is because the heat energy level of the final state is higher than that of the initial state. So, the difference gives a positive value.A compound is made up of 80.0 % C and 20.0 % H. Its molar mass is 30.0 g. What is its molecular formula?
a. C2H6
b. CH
c. C4H12
d. CH3
Answer:
Molecular formula = C₂H₆
Explanation:
Given data:
Percentage of hydrogen = 20.0 %
Percentage of carbon = 80.0 %
Molar mass = 30.0 g
Empirical formula = ?
Solution:
Number of gram atoms of H = 20 / 1.01 = 19.8
Number of gram atoms of C = 80 /12 = 6.7
Atomic ratio:
C : H
6.7/6.7 : 19.8/6.7
1 : 3
C : H = 1 : 3
Empirical formula is CH₃.
Molecular formula:
Molecular formula = n (empirical formula)
n = molar mass of compound / empirical formula mass
Empirical formula = CH₃ = 12×1 +3×1.01 = 15.03 g/mol
n = 30 g/mol / 15.03 g/mol
n = 2
Molecular formula = n (empirical formula)
Molecular formula = 2 (CH₃)
Molecular formula = C₂H₆
_________ is the movement of materials across a cell membrane using cellular energy.
Passive Transport
Active Transport
Answer:
active transport
Explanation:
passive transport does not involve energy
Ammonium Nitrate (NH4NO3), an important fertilizer, produces Dinitrogen monoxide gas (N2O) and water when it decomposes. Determine the mass of the water produced from the decomposition of 25.00 grams of solid Ammonium Nitrate.
Answer:
Mass = 11.23 g
Explanation:
Given data:
Mass of water produced = ?
Mass of ammonium nitrate decomposed = 25.0 g
Solution:
Chemical equation:
NH₄NO₃ → N₂O + 2H₂O
Number of moles of NH₄NO₃ :
Number of moles = mass/molar mass
Number of moles = 25.0 g/ 80.0 g/mol
Number of moles = 0.312 mol
Now we will compare the moles of NH₄NO₃ and H₂O
NH₄NO₃ : H₂O
1 : 2
0.312 : 2/1×0.312 = 0.624 mol
Mass of water formed:
Mass = number of moles × molar mass
Mass = 0.624 mol × 18 g/mol
Mass = 11.23 g
11.23 grams of water produced from the decomposition of 25.00 grams of solid Ammonium Nitrate.
How we calculate moles from mass?
We can determine the moles of any substance by using the equation:
n = W /M, Where:
n = no. of moles
W = given mass
And M = molar mass
Given balanced equation is:
NH₄NO₃ → N₂O + 2H₂O
Also given that mass of NH₄NO₃ = 25 g
Mole of NH₄NO₃ = 25 / 80 = 0.312 mol
From the stoichiometry of the reaction, ratio between NH₄NO₃ and water is 1:2; it means one mole of NH₄NO₃ will produce 2 moles of water.
Moles of water formed = 2 × 0.312 = 0.624 mol
Now we convert this mole to grams through following way:
W = n × M
W = 0.624 × 18 = 11.23 grams
Hence, produced mass of water is 11.23 grams.
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pls help with give brainiest Which statement best explains why the sun's
Please help fast. I will give brainliest!!!
Answer:
Reaction #4
Explanation:
Generally, combustion reactions produce water and carbon dioxide, and the fourth answer choice is the only one that produces both of these compounds. Therefore, the fourth answer choice is the only one that can be a combustion reaction.
The heat in a system is equivalent to the temperature of the system.
True
False
Answer:
False
Explanation:
Heat is the total kinetic energy possessed by molecules the body while temperature is the average kinetic energy possessed by the molecules of the body. Hence, the temperature and heat energy are different.
How many molecules are in 2 moles of O2?
Answer:
Approx 32g
Explanation:
Oxygen has an atomic weight of 15.999. Times to is 32g
How many moles of hydrogen are required to produce 50 moles of methanol
Answer:
search it up ;)
Explanation:
Why can't store gases in open containers
Answer:
They may react in the air and become an acidic gases.
What is the name for a substance made of billions of oppositely charged ions
joined together?
Answer:
Ionic substance
Explanation:
An ionic substance is formed when oppositely charged ions link up to form an infinitely large lattice structure that can only be described in terms of unit cells.
Ionic substances may consist of billions of oppositely charged ions. Ionic substances are hard, have high melting and boiling points and do not conduct electricity in the solid state because the ions are not free in the solid state.
However, in solution or molten state, the substance conducts electricity since the ions which are the charge carriers are now mobile.
write the equilibrium expression for the following reaction.based upon the value of k,would there be more or less product in the equilibrium mixture?why?
CaO(s)+CH4(g)+2H2O(g) ⇄ CaCO3(s)+4H2(g) kp=2344
Answer: [tex]K_p=\frac{[H_2]^4}{[CH_4]^1[H_2O]^2}[/tex]
As value of K is greater than 1, the reaction is forward driven.
Explanation:
Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. For equilibrium constant in terms of pressure , only gaseous reactants and products are considered.
For the given chemical reaction:
[tex]CaO(s)+CH_4(g)+2H_2O(g)\rightleftharpoons CaCO_3(s)+4H_2(g)[/tex]
The expression for [tex]K_p[/tex] is written as:
[tex]K_p=\frac{[H_2]^4}{[CH_4]^1[H_2O]^2}[/tex]
As > 1, the reaction will be favoured in the forward direction and thus more products will be there.
What is the mass, in grams, of one mole of any substance known as?
A. atomic mass
B. molar mass
C. molecular weight
D. atomic number
The answer is B. the molar mass.
The molar mass of a chemical compound is defined as the mass of a sample of that compound divided by the amount of substance in that sample, measured in moles.
why is ethanol a member of the homologous series of alcohols but propane is not
I’m in the exam!
Answer:
I hope it helps..... you can stop at the full-stop
Gene flow adds genetic __________ to a population.
Answer:
Genetic Variation
Explanation:
Gene flow — also called migration — is any movement of individuals, and/or the genetic material they carry, from one population to another. ... If gene versions are carried to a population where those gene versions previously did not exist, gene flow can be a very important source of genetic variation.
28 moles of butane and 228 moles of oxygen are used in the
following reaction. Identify the limiting reagent.
C4H8 + O2 + CO2 + H2O
-butane
-oxygen
-either of the two reactants can be used as a limiting reagent
-none of the above
O₂ as a limiting reactant
Further explanationGiven
28 moles of butene
228 moles of Oxygen
Required
Limiting reactant
Solution
We use the basis for the given reaction because for the name butane it should have the formula C₄H₁₀, while C₄H₈ is butene
Reaction(balanced)
C₄H₈ + 6 O₂ → 4 CO₂ + 4 H₂O
Find limitng reactant from mol : coefficient of reactants
C₄H₈ : 28 : 1 = 28
O₂ : 228 : 6 = 38
O₂ as a limiting reactant (smaller ratio)
Calculate the percentage of yield when 20 grams of sodium chloride solution reacts with an excess amount of silver nitrate solution knowing that 45 grams of silver chloride precipitated
%yield = 91.8
Further explanationGiven
20 g NaCl
45 g AgCl
Required
%yield
Solution
Reaction
NaCl + AgNO₃ ⇒ AgCl + NaNO₃
mol NaCl :
= mass : MW
= 20 g : 58,44 g/mol
= 0.342
mol AgCl from equation :
= 1/1 x mol NaCl
= 1/1 x 0.342
= 0.342
Mass AgCl(theoretical) :
= mol x MW
= 0.342 x 143,32 g/mol
= 49.02 g
%yield = (actual/theoretical) x 100%
%yield = (45/49.02) x 100%
%yield = 91.8
Percentage % yield = 91.8%
Given:
20 g NaCl
45 g AgCl
To find:
% yield=?
The balanced chemical equation will be:
NaCl + AgNO₃ ⇒ AgCl + NaNO₃
First, we need to calculate moles of NaCl.
[tex]\text{Number of Moles}=\frac{\text{Given Mass}}{\text{Molar Mass}} \\\\\text{Number of Moles}=\frac{20}{58.44} \\\\\text{Number of Moles}= 0.342 moles[/tex]
Then, calculate moles of AgCl from equation:
[tex]\text{mol of AgCl}= 1/1 * \text{ mol NaCl}\\\\\text{mol of AgCl}= 1/1 * 0.342\\\\\text{mol of AgCl}= 0.342[/tex]
Mass AgCl(theoretical) :
[tex]\text{Mass of AgCl}= mol * MW\\\\\text{Mass of AgCl}= 0.342 x 143,32 g/mol\\\\\text{Mass of AgCl}= 49.02 g[/tex]
Now, calculate for percentage yield.
[tex]\%yield =\frac{actual}{theoretical} * 100\%\\\\\%yield = (45/49.02) * 100\%\\\\\%yield = 91.8\%[/tex]
The percentage yield will be 91.8%.
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A dune buggy winds over sand dunes in the desert, going a distance of 1500 meters in 180 seconds. What is the average speed, in meters per second rounded to the nearest hundredth, of the dune buggy?
Answer:
8.33 meters per second
Explanation:
1500 meters/180 seconds=1500/180=8.3333 meters per second
A student makes a Venn diagram as a study aid to compare asexual reproduction and sexual reproduction.
Which process belongs in the region marked X?
Fertilization
Vegetative propagation
Binary fission
Sporulation
What are the main differences between asexual reproduction and sexual reproduction?
Asexual reproduction requires two parents and produces non-identical offspring, while sexual reproduction requires only one parent and produces identical offspring.
Asexual reproduction requires two parents and produces identical offspring, while sexual reproduction requires only one parent and produces non-identical offspring.
Asexual reproduction requires only one parent and produces identical offspring, while sexual reproduction requires two parents and produces non-identical offspring.
Asexual reproduction requires only one parent and produces non-identical offspring, while sexual reproduction requires two parents and produces identical offspring.
Two scientists are debating how to classify a new animal species that they have discovered. They observe that the animal is capable of producing sperm.
What statement would they most likely make about the new species?
This animal produces offspring that are genetically different from itself.
This animal produces offspring that are genetically identical to itself.
This animal’s sperm will join with spores to produce offspring.
This animal’s sperm will undergo binary fission to produce offspring.
Koala bears reproduce sexually. Which statement describes how a young koala’s DNA compares to the DNA of its parents?
It has the same DNA as both parents.
All of its DNA comes from its father.
All of its DNA comes from its mother.
Half of its DNA comes from each parent.
Ryder needs to determine the missing term in this set:
sperm, egg, zygote, ________
Which term best completes the set?
binary fission
vegetative propagation
sporulation
fertilization
A scientist is studying two types of worms. Worm X has DNA identical to its parent. Worm Y has a combination of DNA from two parents. The scientist determines that one of the worms has a survival advantage over the other worm.
Which statement correctly summarizes this conclusion?
Worm X reproduces asexually, which gives it genetic variation.
Worm Y reproduces sexually, which gives it genetic variation.
Worm Y reproduces asexually, which gives it more DNA.
Worm X reproduces sexually, which gives it more DNA.
Answer:
gg
Explanation:
Which of the following is/are chemical changes? Select all that apply.
1. water boiling
2. vinegar and baking soda mixing and creating bubbles
3. dumping baking soda into water
4. a bike rusting while it sits outside
At the energy-generating station, the coal is burned. Burning
changes, the coal's chemical energy into sound energy.
true or
false
Answer:
The correct answer is - false.
Explanation:
At the energy-generating station, when the coal is burned, the chemical energy store in the coal converted into thermal energy and light or luminous energy.
The thermic energy generated used to heat and boil the water or liquid to generate the gas and generate the kinetic energy to move the fan that is desgined to generate the electrical energy.
Thus, the statment is false statement as it does not convert into sound energy.
1. Explain how a bright-line spectrum is produced, in terms of excited state,
energy transitions, ground state and subatomic particles?
The characteristics of the atomic models that the energy levels are discrete allow to explain the existence of bright lines in the emission spectra is:
The bright lines are the jump between two energy levels of an atom.
The energy levels of the atoms were initially explained by Bohr's model and later fully resolved and explained by quantum mechanics, in all these models they are discrete levels and there is nothing between them.
When the atoms are in their base state, all the electrons occupy the different levels allowed, before some excitation one of the electrons jumps from one level to another higher, after a period of time this electron falls back to the lower levels directly or by jumps if there are empty intermediate allowed levels, in each fall jump a little energy is released, this is the bright lines in the atomic spectra
The energy of the bright lines matches the difference in energy between the two levels involved.
In conclusion, the characteristics of the atomic models that the energy levels are discrete allow you to explain the existence of bright lines in the emission spectra.
The bright lines are the jump between two energy levels of an atom.
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18. Which factor does NOT affect weather?
1. mountains
2. phases of the moon
3. cloud cover
4. large bodies of water
Answer:
mountains
Explanation:
mountains is the answer because mountains are just there doing nothing
Which of the following compounds contains both ionic and covalent bonds?
A.NaCl
B.CO
C.KI
D.NaOH
Answer:
D.NaOH
Explanation:
The compound that contains both ionic and covalent bonds from the given choices is NaOH, sodium hydroxide.
An ionic bond is formed between a metal and non-metal. In this compound, the metal is the Na and non - metal is the OH. To form this bond type, an atom transfers its electrons to the non-metal to attain stability.
The radical group OH⁻ which acts as a single unit is made up of a covalent bond. It involves the sharing of electrons between two non-metals whose electronegativity difference is very similar to one another.
Questioned document examiners prefer to work with copies of a questioned document in order to avoid damage to the original
material.
O True
O False
Which characteristic of a cell membrane alloes it to control materials entering and leaving a cell?
Answer:
B
Explanation:
The cell membrane is semipermeable that allows the movement of material in and out of the cell. The correct option is B.
What is a cell membrane?The cell membrane, also renowned as the plasma membrane, is detected in all cells as well as serves to differentiate the cell's interior from the outside environment.
The cell's membrane is comprised of a semipermeable lipid bilayer. The cell membrane controls the transport of materials into and out of the cell.
Proteins as well as lipids help compensate cell membranes. Because they are mostly made of lipids, only certain substances can pass through.
Phospholipids are the most common lipid found in membranes. Phospholipids are composed of two layers: outer and inner.
It also provides a consistent environment within the cell. And that membrane serves several purposes. One function is to transport nutrients into the cell, while the other is to transport toxic substances out of the cell.
Thus, the correct option is B.
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HELPPP PLZZZZ :( ONLY ANSWER IF U ACUALLY KNOOOW ALL
Answer:
Net: 1N
Explanation:
1.) Net:1N, direction: left
2.) Net: 1N, direction: down
3.) Net: 0N, no motion
4.) Net: 1N, direction: up
5.) Net: 1N, direction: up
how many grams of oxygen are needed to form 122 g of aluminum oxide?
Mass of O₂ needed : = 57.408 g
Further explanationGiven
122 g of Aluminum oxide
Required
Mass of Oxygen
Solution
Reaction
4Al + 3O₂ → 2Al₂O₃
Mol Al₂O₃(MW=102 g/mol) :
= mass : MW
= 122 g : 102 g/mol
= 1.196
From the equation, mol ratio of O₂ : Al₂O₃ = 3 : 2, so mol O₂ :
= 3/2 x mol Al₂O₃
= 3/2 x 1.196
= 1.794
Mass O₂ (MW = 32 g/mol) :
= mol x MW
= 1.794 x 32
= 57.408 g
A 2.5 molar solution contains 0.97 g of NaOH. What would be the volume of this
solution in mL?
Answer:
9.7 ml
Explanation:
Molarity = 2.5 M
Mass = 0.97g
Volume = ?
The relationship between these quantities is;
Molarity = Number of moles / Volume
Number of moles = Mass / Molar mass
Molar mass of NaOH = 40g/mol
Number of moles = 0.97 / 40 = 0.02425 mol
Volume = Number of moles / Molarity = 0.02425 / 2.5 = 0.0097 L
1000 ml = 1L
x = 0.0097 L
x = 0.0097 * 1000 = 9.7 ml
6. Imagine you are riding a bike, and you hit a large rock in your path. The
rock puts external force on your bike. Which of the following is likely to
happen according to Newton's First Law of Motion?
A. Your bike stops moving forward
B. Your body flies forward.
C. The rock may move backward
D. All of the above
According to Newton's first law of motion,if a large rock hits the bike your body will fly forward as an external force is acting on it.
What is motion?Motion is defined as a phenomenon which is described with respect to change in object's position with respect to time.It is given in terms of displacement,velocity,distance ,acceleration,speed.
Branch of physics which deals with motion of objects without any reference to it's cause is called kinematics while the branch which studies forces and their effects on motion is called as dynamics.
Motion applies to various systems like objects,bodies, matter particles ,radiation ,curvature.There are three laws of motion which are proposed by Newton.Classical mechanics is based on Newton's law of motion.Relativistic mechanics is based on modern kinematics.
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