There are many important laws and theories in science. Which of the following is a law of science?
A living thing is made of at least one cell.
An atom is made of electrons orbiting a nucleus.
Gravity will pull two objects toward each other.
Natural selection will change species to fit their environments.
Answer: Gravity will pull two objects toward each other
Explanation:
Answer:C
Explanation:Gravity
When an alkene is subjected to treatment with Hg(OAc)2 in alcohol followed by reaction with NaBH4, what new class of compound is formed
Answer:
The new class of compound formed is an alcohol.
Explanation:
The treatment of an alkene with Hg(OAc)₂ in alcohol followed by reaction with NaBH₄ gives an alcohol. This reaction is known as oxymercuration-demercuration reaction. It is a two-step pathway which proceeds in the Markovnikov manner. In this reaction, the alkene react with the Mercury salt (Hg(OAc)₂) and a nucleophile (alcohol) to form an organomercury intermediate. The intermediate's carbon-mercury bond is then converted to carbon-hydrogen bond by the reaction with NaBH₄. An alcohol is then produced.
Before bonding, the atom’s electrons spend most of their time ___________________ the nuclei of each atom.
Answer:
Around.
Explanation:
A chemical formula helps scientists to show or illustrate the type and number of atoms present in a particular molecule or compound by using numerical subscript, ions and atomic symbol of a chemical element.
This ultimately implies that, a chemical formula is used to describe or denote the exact amount of atoms that make up a molecule or compound.
The type of bond which is formed when the atoms of a chemical element are sharing electrons is known as covalent bond. Thus, when two (2) atoms of a chemical element comes close together, the nucleus of one of the atom attracts the other atom's electrons.
However, before bonding takes place, the atom's electrons spend most of their time around the nuclei of each atom.
An alcohol is 62.04 % C and 10.43 % H by mass. The rest is oxygen. What is the empirical formula of the alcohol
Answer: The empirical formula is [tex]C_3H_6O[/tex]
Explanation:
If percentage are given then we are taking total mass is 100 grams. So, the mass of each element is equal to the percentage given.
Mass of C = 62.04 g
Mass of H = 10.43
Mass of O = (100-(62.04+10.43)) g = 27.53 g
Step 1 : convert given masses into moles.
Moles of C = [tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{62.04g}{12g/mole}=5.17[/tex]moles
Moles of H =[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{10.43g}{1g/mole}=10.43moles[/tex]
Moles of O = [tex]\frac{\text{ given mass of O}}{\text{ molar mass of O}}= \frac{27.53g}{16g/mole}=1.72moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C = [tex]\frac{5.17}{1.72}=3[/tex]
For H = [tex]\frac{10.43}{1.72}=6[/tex]
For O =[tex]\frac{1.72}{1.72}=1[/tex]
The ratio of C :H : O= 3: 6 : 1
Hence the empirical formula is [tex]C_3H_6O[/tex]
A piece of silver metal weighting 194.3 g is placed in a graduated cylinder containg 242.0 ml of water.the volume of water now reads 260.5 ml. calculate the denstyof the metal
Answer:
10.50 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\[/tex]
volume = final volume of water - initial volume of water
volume = 260.5 - 242 = 18.5 mL
We have
[tex]density = \frac{194.3}{18.5} \\ = 10.5027[/tex]
We have the final answer as
10.50 g/mLHope this helps you
Which statements describe how heat flows in foil?
Check all that apply.
O Heat flows in all directions.
O Heat flows from left to right only.
The atoms on top of the foil absorb heat first.
O The atoms near the candle absorb heat first.
O Heat flows from the cooler atoms to the warmer
atoms.
O Heat flows from the warmer atoms to the cooler
atoms.
Answer: ADF
Explanation: On my moms it’s right
The statements describe how heat flows in foil are heat flows in all directions, Heat flows from the cooler atoms to the warmer atoms, Heat flows from the warmer atoms to the cooler atoms. Therefore, option A, D and E are correct.
What is heat ?Heat is the result of the movement of kinetic energy within a material or an item, or from an energy source to a material or an object. Radiation, conduction, and convection are the three mechanisms through which such energy can be transferred.
Due to its extraordinary thinness and shine, aluminum foil has special characteristics. It bounces heat waves back outward rather than effectively absorbing or conducting heat. This explains why aluminum foil cools almost instantly after being removed from the oven, even after it has been there for some time.
The majority of the radiation released by a heated object is reflected onto the object when it is wrapped in reflective aluminum foil.
Thus, option A, D and E are correct.
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When warm air is forced upward along a cold front what might happen?
Answer: With the cold front, warm air is rapidly forced upward (like the shavings) in advance of the actual front (the “cutter”), creating towering cumulus clouds, some hard showers and quite possibly a few gusty thunderstorms followed by a push of cooler and drier air in its wake.
Explanation:
A species of butterfly lives in a warm climate. The butterflies feed on the nectar of tropical flowers. Birds eat the butterflies, and they prefer to eat the butterflies with brighter wings.
20 points
What would most likely cause this species to become extinct?
a mutation resulting in darker wings
a decrease in the birds that eat the butterflies
the destruction of the butterflies’ environment
overproduction of butterfly offspring
Answer: the destruction of the butterflies’ environment
Explanation:
A mutation that would result in darker wings will mean that the birds that prey on them will stop eating a lot of them so this won't lead to extinction.
A decrease in the birds that eat the butterflies will also mean that the butterflies will survive more because they will have less predators.
Overproduction of butterfly offspring means more butterflies so they will not go extinct.
If their habitat was destroyed however, the butterflies might find it hard to survive as any new environment they go to might not be suitable leading to their extinction.
Answer:
I believe it is c
Explanation:
which of the following is NOT a clue that a chemical reaction has taken place?
A:release of gas
B:color change
C:mixing of the reactants
D:formation of a precipitate
Answer:
A
Explanation:
My reason is color change is an example
Mixing reactants is a chemical change clue
formation of precipitate is a clue
so that leaves A
7. Which of the following is not a characteristic of a solution?
a. It is a uniform mixture
b. It will scatter a beam of light
c. The solute and solvent cannot be distinguished by the naked eye
d. The solute particles cannot be separated by filtering
what is the correct meaning of the word justify?
he was not sure how he would be able to justify. his actions to his family.
a. change for the better
b. prove to be right
c. claim to understand
d. describe in detail
I’ll mark brainliest!!!
What are the products of a fission reaction? Check all that apply.
-lighter atoms
-energy
-heavier atoms
-neutrons
-protons
Answer: lighter atoms
energy
neutrons
Explanation:
A nuclear fission is simply defined as a nuclear reaction whereby the nucleus of an atom is being divided into smaller nuclei which are also lighter. An energy is also released when this occurs.
Therefore, the products of a fission include lighter atoms, energy and neutrons.
Answer:
lighter atoms
energy
neutrons
Explanation: took test
how many electrons are shared in the bond between a hydrogen atom and a cardon atom in a molecule?
Answer:
It forms from two hydrogen atoms, each with one electron in a 1s orbital. Both hydrogen atoms share the two electrons in the covalent bond, and each acquires a helium-like electron configuration.
okay this is not school related but how do you not fall for some one so hard .
Answer:
Love is not only the thing in this world!
Study hard, you can choose a better way of life.
An aqueous solution of 6.70 M ammonia, NH3, has a density of 0.950 g/mL. The percent by mass of NH3 in the solution is %.
Answer:
12.01% by mass
Explanation:
Percent by mass is 100 times the mass of solute (ammonia) over the mass of the solution. In molarity, we have the moles of ammonia per liter of solution. There are 6.70moles of NH3 in 1L. Thus, we need to convert the moles of ammonia to grams and the liters of solution to grams:
Mass ammonia - Molar mass: 17.031g/mol-
6.70moles * (17.031g / mol) = 114.1g NH₃
Mass solution:
1L * (1000mL / 1L) = 1000mL * (0.950g/mL) = 950g
Percent by mass:
114.1g NH₃ / 950g * 100 =
12.01% by massPlease help me thanks so much....I’ll mark you?!?!:)))) ( 15 points)
Answer:
the first one
Explanation:
Chrysocolla is a copper mineral that contains .016 % silicon. What is the mass of silicon present in 1.5kg of this mineral
Answer:
.24 mg
Explanation:
The mineral contains .016 % silicon
mass of the mineral = 1.5 kg
mass of silicon = 1.5 x .016 %
= 1.5 x .016 / 100
= 24 x 10⁻⁵ kg
= 24 x 10⁻² mg
= .24 mg .
Calculate the energy required to heat of ethanol from to . Assume the specific heat capacity of ethanol under these conditions is . Be sure your answer has the correct number of significant digits.
Answer:
17 kJ
Explanation:
Calculation for the Calculate the energy required to heat 0.60kg of ethanol from 2.2°C to 13.7°C.
Using this formula
q = mC∆T
Where,
q represent Energy
m represent Mass of substance=0.60kg=600g
C represent Specific heat capacity=2.44J·g−1K−1.
∆T represent change in Temperature=2.2°C to 13.7°C.
Let plug in the formula
q=(0.60 kg x 1000 g/kg)(2.44 J/gº)(13.7°C-2.2°C)
q = (600g)(2.44 J/gº)(11.5º)
q=16.836 kJ
q= 17 kJ (Approximately)
Therefore the energy required to heat 0.60kg of ethanol from 2.2°C to 13.7°C will be 17 kJ
A chemist dissolves 240mg of pure barium hydroxide in enough water to make up of solution. Calculate the pH of the solution. (The temperature of the solution is .)
Answer:
pH = 12.22
Explanation:
... To make up 170mL of solution... The temperature is 25°C...
The dissolution of Barium Hydroxide, Ba(OH)₂ occurs as follows:
Ba(OH)₂ ⇄ Ba²⁺(aq) + 2OH⁻(aq)
Where 1 mole of barium hydroxide produce 2 moles of hydroxide ion.
To solve this question we need to convert mass of the hydroxide to moles with its molar mass. Twice these moles are moles of hydroxide ion (Based on the chemical equation). With moles of OH⁻ and the volume we can find [OH⁻] and [H⁺] using Kw. As pH = -log[H⁺], we can solve this problem:
Moles Ba(OH)₂ molar mass: 171.34g/mol
0.240g * (1mol / 171.34g) = 1.4x10⁻³ moles * 2 =
2.80x10⁻³ moles of OH⁻
Molarity [OH⁻] and [H⁺]
2.80x10⁻³ moles of OH⁻ / 0.170L = 0.01648M
As Kw at 25°C is 1x10⁻¹⁴:
Kw = 1x10⁻¹⁴ = [OH⁻] [H⁺]
[H⁺] = Kw / [OH⁻] = 1x10⁻¹⁴/0.01648M = 6.068x10⁻¹³M
pH:
pH = -log [H⁺]
pH = -log [6.068x10⁻¹³M]
pH = 12.22What happens to thermal energy during a chemical reaction?
Answer:
Chemical reaction often involved changes energy due to the breaking and formation of bonds. Reaction in which energy is released are exothermic reaction,while those that take in heat energy are endothermic.
1 If 5.80 L of gas is collected at a pressure of 92.0 kPa, what volume will the same gas occupy at 101.3 kPa if the temperature stays constant
Answer:
The volume that the same gas will occupy at 101.3 kPa if the temperature is kept constant is 5.27 L.
Explanation:
As the volume increases, the particles (atoms or molecules) of the gas take longer to reach the walls of the container and therefore collide with them less times per unit of time. This means that the pressure will be lower because it represents the frequency of collisions of the gas against the walls. In this way pressure and volume are related, determining Boyle's law that says:
"The volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure"
Boyle's law is expressed mathematically as:
P * V = k
Now it is possible to assume that you have a certain volume of gas V1 that is at a pressure P1 at the beginning of the experiment. If you vary the volume of gas to a new value V2, then the pressure will change to P2, and it will be fulfilled:
P1 * V1 = P2 * V2
In this case, you have:
P1= 92 kPaV1= 5.80 LP2= 101.3 kPaV2= ?Replacing:
92 kPa* 5.80 L= 101.3 kPa* V2
and solving, you get:
[tex]V2=\frac{92 kPa* 5.80 L}{101.3 kPa}[/tex]
V2= 5.27 L
The volume that the same gas will occupy at 101.3 kPa if the temperature is kept constant is 5.27 L.
From the chair conformation, rotate about the carbon-carbon bonds of the ring to form a boat conformation. In the boat conformation carbon atoms 1 and 4 are both above (they could also both be below) the plane described by carbon atoms 2, 3, 5 and 6. Look through each of the C-C bonds in the cyclohexane ring. Do you observe any eclipsing interactions?
What is the movement of air during the day where land and water meet? Cooler sea air moves toward land, where conduction from the land warms it. , . Direction cannot be predicted; it must be observed. . Cooler air over land moves toward the water, where it is warmed by radiation.
I hope I'm not late, but it's "Cooler air over land moves toward the water, where it is warmed by radiation."
What is the most effective long-term solution to reduce the amount of carbon dioxide emissions
Drive less
Find alternatives to fossil fuels
Increase gas mileage on cars
Recycle the gas
Answer:
Find alternatives to fossil fuels
Explanation:
The most effective long - term solution to reduce the amount of carbon dioxide emission is to find alternatives to fossil fuels.
Fossil fuels consumption and use in most industrial processes are some of the leading causes of huge carbon signatures in the atmosphere.
When fossil fuels are broken down, they release carbon dioxide into the atmosphere. Fossil fuels have become the main stay energy sources in the world today. An alternative to them will serve the ecosystem well.What is the mass of 0.5 moles of ammonia, NH3?
Answer:
Mass = 8.5 g
Explanation:
Given data:
Mass of ammonia = ?
Number of moles = 0.5 mol
Solution:
Formula:
Mass = number of moles × molar mass
Molar mass of ammonia = 17 g/mol
By putting values,
Mass = 0.5 mol × 17 g/mol
Mass = 8.5 g
in a covalent bond, the electrons are _____
Explanation:
In a covalent bond the electrons are simultaneously attracted by the two atomic nuclei.
In a covalent bond the electrons are; simultaneously attracted by the two atomic nuclei.
What is Covalent bonding?Covalent bonding can be defined as the sharing of electrons between two atoms.
The Polar covalent bonds share electrons unequally, while nonpolar covalent bonds share electrons equally.
We know that
Polar covalent bond is defined as a chemical bond in which electrons are shared unequally or unevenly between two atoms.
Non-polar covalent bond is defined as a chemical bond in which electrons are shared evenly or equally between two atoms.
Therefore, In a covalent bond the electrons are; simultaneously attracted by the two atomic nuclei.
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The student is now told that the four solids, in no particular order, are magnesium bromide (MgBr2), sugar (C6H12O6), butanoic acid (C3H7COOH), and potassium bromide (KBr). Assuming that conductivity is correlated to the number of ions in solution, rank the four substances based on how well a 0.20 M solution in water will conduct electricity. Rank from most conductive
Answer:
MgBr2 > KBr > C3H7COOH > C6H12O6
Explanation:
A strong electrolyte is a solution that dissociate completely in solution. A weak electrolyte does not dissociate completely in solution. The more the number of particles in solution, the more the conductivity of the solution.
For the substances Lister in the question;
MgBr2(aq) ------> Mg^2+(aq) + 2Br^-(aq)
KBr(aq) -----> K^+(aq) + Cl^-(aq)
C3H7COOH(aq) ------->C3H7COO^-(aq) + H^+(aq) (poorly dissociates)
C6H12O6 does not dissociate because it is molecular
Please help me thanks so much....I’ll mark you?!?!:)))) (15 points)
Answer:
a penny that has turned green
Explanation:
a chemical change is when a substance combines with another to form a new substance. the other answer choices doesn't form a new substance.
Propane is often used in stoves and cooktops as a source of heat. The combustion of propane yields water and carbon
unbalanced chemical reaction is represented by the ball-and-stick diagrama shown.
How many molecules of carbon dioxide and water are produced during the combustion of propane? Move numbers to
the equation and show that mass is conserved.
+
+
Propane molecule
Oxygen molecules
Carbon dioxide molecule
Water molecule
Legend
Hydrogen
atom
Oxygen
atom
Carbon
atom
2
3
Answer: 3 molecules of carbon dioxide and 4 molecules of water are produced during the combustion of propane.
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.
The balanced chemical reaction for combustion of propane is:
[tex]C_3H_8+5O_2\rightarrow 3CO_2+4H_2O[/tex]
3 molecules of carbon dioxide and 4 molecules of water are produced during the combustion of propane.
TiCl4+H2O-->TiO2+HCl I need to balance this
Answer: The answer is TiCl4 + 2H2O --> TiO2 + 4HCl
Explanation: Every element is equal on both sides.
Ti- 1 Ti-1
Cl- 4 Cl-4
H- 4 H-4
O- 2 O-2