Answer:
The burning of a candle is both a physical and a chemical change.
Explanation:
Plz mark brainliest thanks
D) 7
20 points
2. How does the concept of conservation of mass apply to chemical
reactions? (hint: the Law of Conservation of Mass) *
a) the reactants and products have exactly the same molecules
b) the change in the amount of matter is equal to the change in energy
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c) the reactants and products have exactly the same atoms
d) the change in the amount of matter is only a small percentage of the total mass
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3. How many Oxygen (O) atoms are in the chemical formula below?. *
Answer:
the reactants and products have have exactly the same molecules
The reactants and products have exactly the same atoms, therefore the concept of conservation of mass applies to chemical reactions. Therefore, option (b) is correct.
What is the law of conservation of matter?According to this law, matter can neither be created nor destroyed, but can be converted from one form to another. So the same number and type of atoms in a chemical reaction before and after the chemical change are present.
The initial substances or reactants change into different substances or products in any chemical change. Both the reactants and products are made up of atoms as all matter is made up of atoms.
The matter is conserved as the equal number of atoms of each element in the reactants and products, and the total mass of the reactants must equal the total mass of the products.
The law of conservation of mass can be only followed in a chemical reaction if the reactants and products have exactly the same atoms.
Learn more about the law of conservation of matter, here:
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prove you understand the development of democracy in Athens and how it influenced the government of the United States.
For this assignment, you will write two paragraphs:
In paragraph one, you will explain at least three ways that democracy in Athens influenced the United States government.
In paragraph two, you will explain at least three differences between Athenian and American democracy.
Answer:
The original U.S. voting system had some similarities with that of Athens. In Athens, every citizen could speak his mind and vote at a large assembly that met to create laws. Citizens were elected to special councils to serve as organizers, decision-makers, and judges. The Greek idea of democracy was different from present-day democracy because, in Athens, all adult citizens were required to take an active part in the government. ... This form of government is called direct democracy. The United States has a representative democracy.
Can you help me please
Answer:
Explanation:
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In a single molecule of water, two hydrogen atoms are bonded to a single oxygen atom by _____.
A) hydrogen bonds
B) nonpolar covalent bonds
C) polar covalent bonds
D) ionic bonds
Answer:
C) polar covalent bonds
Explanation:
Polar covalent bonding can be regarded as a chemical bond that involves a pair of electrons which is
unequally shared between two atoms.
The electron are not shared equally as a result of one of the atom spending more time with the electron compare with the other atom. It is one whereby atoms having different electronegativities involves themselves in sharing electrons in a covalent bond
Help please for this problem.
which statement about atoms is correct
A atoms contain protons and electrons in the nucleus
B Neutrons are negatively charged
c protons are positively charged
D the nucleon number is the number of neutrons
Answer:Protons are positively charged is the correct statement about an atom
I've also corrected the other statements
Atoms contain protons and neutrons in their nucleus
Neutrons posses no charge and are neutral
The nucleon number is the total number of protons and neutrons in a nucleus
Which best explains what happens to the carbon atoms in carbon dioxide during photosynthesis?
A They are incorporated into molecules of sugar.
B They are transformed into oxygen atoms.They are transformed into oxygen atoms.
C They are broken down into subatomic particles.They are broken down into subatomic particles.
D They are destroyed to release energy.They are destroyed to release energy.
c i think
Explanation:
if it's not look it up
What is the energy of a photon of violet light with a frequency of 7.79*[tex]10^{14}[/tex] [tex]s^{-1}[/tex]? (answer in joules)
Answer:
[tex]E=5.16\times 10^{-19}\ J[/tex]
Explanation:
Given that,
The frequency of violet light, [tex]f=7.79\times 10^{14}\ Hz[/tex]
We need to find the energy of a photon. The formula for the energy of a photon is given by :
[tex]E=hf\\\\E=6.63\times 10^{-34}\times 7.79\times 10^{14}\\\\E=5.16\times 10^{-19}\ J[/tex]
So, the energy of a photon is equal to [tex]5.16\times 10^{-19}\ J[/tex].
The gravitational force between two masses is proportional to
A.
the difference between the masses.
B.
the first mass divided by the second mass.
C.
the product of the masses.
D.
the sum of the masses.
Answer:
D.
the sum of the masses.
Explanation:
A solution of 1.8274g of a polypeptide in 274mL of a aqueous solution has an osmotic pressure at 31.40 degrees C of 2.012 mmHg. The approximate molecular weight of this polymer is _____ g/mol.
Answer: Hence, the approximate molecular weight of the poymer is 64106 g/mol
Explanation:
[tex]\pi=CRT[/tex]
where,
[tex]\pi[/tex] = osmotic pressure of the solution = 2.012 mm Hg = 0.0026 atm
i = Van't hoff factor = 1 (for non-electrolytes)
Mass of solute (polypeptide) = 1.8274 g
Volume of solution = 274 mL
R = Gas constant = [tex]0.0821Latm/Kmol[/tex]
T = temperature of the solution = [tex]31.40^0C=(273+31.40)K=304.4K[/tex]
Putting values in above equation, we get:
[tex]0.0026=\frac{1.8274 g\times 1000}{M\times 274ml}\times 0.0821\times 304.4[/tex]
[tex]M=64106g/mol[/tex]
Hence, the approximate molecular weight of the poymer is 64106 g/mol
Which statements correctly describe the human skeletal system?
O A. The skeletal system produces red blood cells.
B. Once made, bones become solid structures.
OC. Adult bones are made of non-living materials only.
D. There are many kinds of joints.
OE. Joints are bones that can bend.
Answer:
A
Explanation:
Well, the human skeletal system produce red blood cells into and for the body.
Solid sodium reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many g of hydrogen gas are formed when 125.0 g of sodium are added to water?
2Na + 2H2O → 2NaOH + H2
If 0.700 moles Ag is reacted with 10.0 g S, is sulfur or aluminum the limiting reactant?
Answer: [tex]S[/tex] is the limiting reagent
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} S=\frac{10.0g}{32g/mol}=0.3125moles[/tex]
[tex]\text{Moles of} Ag=0.700moles[/tex]
[tex]2Ag+S\rightarrow Ag_2S[/tex]
According to stoichiometry :
1 mole of [tex]S[/tex] require = 2 moles of [tex]Ag[/tex]
Thus 0.3125 moles of [tex]S[/tex] will require=[tex]\frac{2}{1}\times 0.3125=0.6250moles[/tex] of [tex]Ag[/tex]
Thus [tex]S[/tex] is the limiting reagent as it limits the formation of product and [tex]Ag[/tex] is the excess reagent.
SOMEONE HELP ME ASAP!!!
Answer:
A
Explanation:
Which statement are part of the safety protocol for this lab experiment?
Answer:
Always wear safety goggles when performing an experiment.
Use caution when constructing the track.
Ensure that the track is clear before releasing cars.
Report all accidents to the teacher.
Explanation:
How many moles of water are there in 45 g of water?
a) 1.0 moles
b) 1.5 moles
c) 2.0 moles
d) 2.5 moles
Answer:
d
Explanation:
can you help me with my question In the extended simile of the underlined passage from Paragraph 15 of "A Wagner Matinee," the narrator makes an observation about the soul that aring rokol been A. it is like a strange moss on a dusty shelf that, with excruciating suffering, can wither and die y for I the be B though after excruciating suffering it may seem to wither, the soul never dies, C. excruciating, interminable suffering that goes on for half a century can kill the soul.
Characteristics of a substance that describe its' ability to change into a different substance are called?
Hurry hurry hurry plz plz
Jonathan’s claim: light is always the same, even when it is emitted by a different light sources(light the sun and a light bulb)
Question 1: do you agree or disagree with his claim?
Question 2: what evidence from your observations within our lesson prove your point?
Answer:
Jonathan’s claim is right.
Explanation:
Jonathan’s claim is right because photons emitted by both sources i.e. sun and the light bulb has the same wavelength which looks practically identical to each other. But some differences in the light spectrum of sun and a light bulb i. e. light bulb has more infrared output than visible and ultraviolet while on the other hand, sun has more visible light than infrared and ultraviolet radiations so we can say that Jonathan's claim is right about the emission of light.
Which is most often used to destroy bacteria?
pls pls help i need this soo bad ill give brainliest
Answer:
Mycelial threads
Explanation:
Through the mycelium threads, a fungus or in this case a mushroom absorbs nutrients from its environment. It does this in a two-stage process. First, the hyphae secrete enzymes onto or into the food source, which break down biological polymers into smaller units such as monomers. Mycelium is an important food source for many soil invertebrates.
Answer:
wassssssssssssssssap
Explanation:
if water is added to a 0.70 molar solution of CuSO4 what will change
A. molarity will increase
B. Molarity will decrease
C. the amount of CuSO4 will decrease
D. No change in molarity or amount of salute
Answer:
B. Molarity will decrease
Explanation:
Molarity is one of the measures of the molar concentration of a solution. It is calculated by dividing the number of moles of the solute by the volume of the solvent. This means that the higher the amount of solute in relation to the volume of solvent, the higher the molarity of that solution.
In essence, adding water to a solution dilutes it i.e it increases the solvent's volume in relation to the solute, causing the molarity to decrease. In a nutshell, diluting a solution (by adding water or more solvent) causes the molarity of such solution to decrease. For example, if water is added to a 0.70 molar solution of CuSO4, the molarity of the solution will DECREASE.
Los termómetros de mercurio no pueden medir temperaturas menores a -30oC debido a que a esa temperatura el Hg
se hace pastoso. ¿Podrías indicar a qué temperatura Fahrenheit y Kelvin corresponde?
Answer:
243.15 K y -22 F
Explanation:
Para convertir la temperatura desde grados Celsius (°C) a kelvin (K) se debe sumar 273.15 K:
K = °C + 273.15 = -30°C + 273.15 K = 243.15 K
Para convertir desde grados Celsius (°C) a Fahrenheit (F), se multiplica por 9/5 y se suma 32, como sigue:
F = (9/5 x °C) + 32 = (9/5 x (-30°C)) + 32= -22 F
Por lo tanto, una temperatura de -30°C corresponde a 243.15 Kelvin y -22 grados Fahrenheit.
What do the Beluga and the sea duck have in common in the food web?
Answer: they both eat fish
Explanation:
During the combustion of methane (CH4), one mole of methane gas combines with two moles of oxygen gas (O2) to produce one mole of carbon dioxide gas (CO2) and two moles of water vapor. Which of the following chemical equations correctly represents the combustion of methane described above
Answer:
CH4(g) +2O2____ CO2(g) +2H2O (l)
What is an important effect of gravity?
Answer:
pulling objects with mass closer to each other
Explanation:
that is the only role of gravity
Facts about flooding
Answer:
No region is safe from flooding. All 50 states are subject to flash floods.[1]
Flash floods can bring walls of water from 10 to 20 feet high.[2]
A car can be taken away in as little as 2 feet of water.[3]
To stay safe during a flood, go to the highest ground of floor possible. If your skin comes in contact with flood water, make sure to wash it with soap and disinfected water because the contents are unknown.[4]
Flooding is caused by spring thawing (snow and frozen grounds melting in the spring), heavy rains, snow melt runoffs, flash floods, and mudflows.[5]
Floods are the most widespread natural disaster aside from wildfires. 90% of all U.S. natural disasters declared by the President involve some sort of flooding.[6]
In preparation for a flood, it is important to stock up on first aid items, non-perishable foods, 3 gallons of water per person for 3 days, battery operated radio for weather reports, extra batteries, personal hygiene necessities.[7]
Based on Floodsmart, a 2,000 square foot home undergoing 12” of water damage could cost more than $50,000.[8]
Since flood damage is almost never covered by homeowners insurance, flood insurance is important for people living in high-risk flood zones.[9]
To stay safe during a flood, go to the highest ground of floor possible. If your skin comes in contact with flood water, make sure to wash it with soap and disinfected water because the contents are unknown.[10]
Communities particularly at risk are those located in low-lying areas, near water, or downstream from a dam.[11]
When you have a molecule that has one side with access to electrons, and one side that is deficient in electrons, a(n) ______ forms.
A. Bonds
B. Ion
C. Dipole
D. Charge
Only respond if you actually know the answer!!!
Answer:
C. Dipole
Explanation:
When a molecule is unevenly charged but overall neutral, for example, one atom has a negative charge, and one has a positive charge, they balance each other out when they bond and are known as a polar molecule. Dipole just means 2 poles (positive and negative).
how many grams of Al(no2)3 should be added to 1.3L of water to prepare a 2.0M solution
Answer: 429 grams of [tex]Al(NO_2)_3[/tex] should be added to 1.3 L of water to prepare 2.0 M solution
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.
[tex]Molarity=\frac{n}{V_s}[/tex]
where,
n = moles of solute [tex]Al(NO_2)_3[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{165g/mol}[/tex]
[tex]V_s[/tex] = volume of solution in Liters
Now put all the given values in the formula of molarity, we get
[tex]2.0M=\frac{xg}{165g/mol\times 1.3L}[/tex]
[tex]x=429g[/tex]
Therefore, 429 grams of [tex]Al(NO_2)_3[/tex] should be added to 1.3 L of water to prepare 2.0 M solution
What is this what is this
Answer:Attemted Failed
Maybe try to search
In a different way like:
what is the ingredient of cake
Instead of
how to make Cake
15g of sugar and 10g of water are measured separately. The sugar is dissolved in the water. What will
the mass of the solution be?
Answer: a) No, both are different.
b) Ramesh- 9.9%
Sarika - 10%
Explanation:
According to the solution prepared by Ramesh,
Mass of sugar he took (Solute) = 10 g
Mass of water he took (Solvent) = 100 g
Thus Mass % of the solution =
According to the solution prepared by Sarika,
Mass of sugar she took (Solute) = 10 g
Mass of Solution she took = 100 g
Thus Mass % of the solution =
Explanation: