The molar mass of water (H2O) is 18. 0 g/mol. A sample of water has a mass of 18. 0 g. How many moles of water are contained in this sample? 1. 00 mole 18. 0 moles 36. 0 moles 324 moles.
1 mole of water are contained in the given sample of water of 18.00 grams.
How we calculate the moles?Moles of any substance will be calculated as:
n = W/M, where
W = given or required mass
M = molar mass
In the question given that,
Molar mass of water H₂O = 18 g/mole
Given mass of water H₂O = 18 grams
Now we put all these values in the above equation, we get
Moles of H₂O = 18 grams / 18 g/mole = 1 mole
Hence, option (1) is correct, i.e. 1 mole of water is present.
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What is the main difference between a physical change and a chemical change? Select all
correct answers. Hint: 2 correct answers.
A. A physical change does not change the substances composition.
B. A physical change changes a one or more substance into a new substance.
C..A chemical change does not change the substances composition.
D. A chemical change changes a one or more substance into a new substance.
Answer:
A, D
Explanation:
Which of the following is a way that groundwater depletion affects streams? a. Lower water level b. Loss of vegetation c. Wildlife disruption d. All of the above.
The affect of ground water depletion is Lower water level, Loss of vegetation and Wildlife disruption.
What is ground water?The amount of water that is present below the upper surface area of the land, which are not easily accessible is known as ground water.
And this ground water keeps the soil hydrated and responsible for good vegetation by providing many minerals through water, wildlife is also depends on the ground water as they provide survival for many species. If the ground water is deplected then it also affects the flow of streams and lower water level.
Hence option (d) is correct i.e. All of the above.
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Answer
D. All of the above
Explanation
what is the final temperature of 520.1 g of water (specific heat =4.18 J/g × °C) at 24.2 °C that absorbed 950 J of heat
Answer:
The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs.
Explanation:
The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object. The direction of the force on the first object is opposite to the direction of the force on the second object. Forces always come in pairs - equal and opposite action-reaction force pairs.
Janice needs to have a gastro-intestinal study. So she is given 375 mg of radiocontrast dye containing Barium-142. The half-life of Ba-142 is 10.6 minutes and its decay is followed by -ray. After one half -life, of Ba-142 remains . After 31.8 minutes , of Ba-142 remains . After half-lives, 11.7 mg of Ba - 142 remains . After minutes , 0.366 mg of Ba - 142 remains. Finally, after approximately 3.5 hours - half-lives , only 0.000358 mg remains . The dye is no longer visible to the Xray and Janice's study is over .
After one half life, 188mg
46.9 mg of Ba-142
After 5 half lives
After 106 minutes
20 half lives , only 0.000358 mg remains
Hope this helps
The given statement could be filled in as follows:
After one half-life, 188mg
46.9 mg of Ba-142 After 5 half-lives
After 106 minutes 20 half-lives, only 0.000358 mg remains.
What is half-life?Half-life is described as the meantime necessary of 1/2 of radioactive decomposition's sample to break up.
In the given study,
Amount of Radiocontrast dye [tex]= 375 mg[/tex]
Half-life [tex]= 10.6[/tex] minutes
Therefore,
The amount left post 1 half-life = 188 mg
Now,
The amount left post 5 half-lives [tex]= 46.9 mg[/tex]
Lastly,
The amount left post 20 half-lives [tex]= 0.000358 mg[/tex]
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What are The factor(s) which help in the prediction of trends in the periodic
table
Answer:
number of protons in the nucleus, number of energy levels, and the shielding effect.
Explanation:
I hope this helps :)
At a certain temperature, the value of the equilibrium constant, K, for the reaction represented above is 2.0 x 105. What is the value for the reverse reaction at the same temperature
The value of the equilibrium constant for the reverse reaction is 5 × 10⁻⁶.
Equilibrium constantThe equilibrium constant is the value of the reaction quotient at equilibrium.
Given that at a certain temperature, the value of the equilibrium constant, K, for the reaction represented above is 2.0 × 10⁵.
We require the equilibrium constant for the reverse reaction at the same temperature.
Equilibrium constant for reverse reactionLet K' be the equilibrium constant for the reverse reaction.
So, we have that K' = 1/K
Substituting the value of K into the equation, we have
K' = 1/K
K' = 1/(2.0 × 10⁵)
K' = 1/2.0 × 1/10⁵
K' = 0.5 × 10⁻⁵
K' = 5 × 10⁻⁶.
So, the value of the equilibrium constant for the reverse reaction is 5 × 10⁻⁶.
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Stephanie notices that the Moon rises at 7 PM local time in the east, over the peach tree in her garden. Where and when can she expect to see the Moon rise the next day?
A) At 8 P.M. in the same place
B) At 7 P.M. in the same place
C) At 6 P.M. in the opposite direction
D) At 7 P.M. in the opposite direction
Answer:
b
Explanation:
because they can't change over 1 day it's takes time
Answer:
b
Explanation:
When you cook food in a hot pan, which statement is correct?
Answer:
the water evaporates
Explanation:
have a good day
If an asteroid were going to impact Earth, would you prefer to know in advance or let the NEO remain a mystery until impact? Why?
Answer:
I think you're supposed to answer that yourself because it's asking your personal opinion. I'd personally like to know in advance
Which statement explains why the element carbon forms so many compounds?
1
Carbon atoms combine readily with oxygen
2
Carbon atoms readily attract electrons.
3
Carbon readily forms ionic bonds with other carbon atoms.
4
Carbon readily forms covalent bonds with other carbon atoms.
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Answer:
3
Carbon readily forms ionic bonds with other carbon atoms.
Explanation:
Which group of elements are the peaks on the graph?
A. alkali metals
B. alkaline earth metals
C. transition metals
D. halogens
E. inner transition metals
F. noble gases
What is the number of electrons in silicon-30
The equation below represents a chemical reaction.
Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g)
A 5.00-g sample of zinc is added to hydrochloric acid. The amount of hydrochloric
acid is sufficient to allow the zinc to react completely. What mass of hydrogen gas
does this reaction produce?
Answer:
0.0308 g
Explanation:
i got it right
When you bring two drops of water near each other and allow them to touch, they combine immediately and become one drop. This happens mainly because
Answer:
This is because water molecules are made of atoms. Atoms may have special ends that attract to each-other magnetically, causing the water to look like it merges into 2 different drops.
Lumps of sodium carbonate react more slowly with dilute nitric acid than powdered sodium carbonate.
Use ideas about collisions to explain why.
Since rate of reaction depends on the surface area of the reactants, lumps of sodium carbonate react more slowly with dilute nitric acid than powdered sodium carbonate.
Factors affecting reaction rateThe rate of reaction is affected by many factors among which is the surface area of the reactants. We must note that the greater the surface area the quicker the rate of reaction.
As such, the surface area of the powdered sodium carbonate is greater than that of the lumps of sodium carbonate. Therefore, lumps of sodium carbonate react more slowly with dilute nitric acid than powdered sodium carbonate. This is because the particles of the powdered sodium carbonate collide more easily with the acid molecules than the lumps of sodium carbonate.
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I am single and I would like to know am I going to find my soulmate this year or next year?
WILL GIVE BRAINLIEST! Which statement correctly describes the properties of bases?
Basic solutions are colored blue.
Bases generate [OH–] ions in solution.
Bases are solutions with a pH less than 7.
Bases do not have the ability to injure skin and eyes.
Answer:
Acids, Bases, and the pH Scale
The terms acid and base describe chemical characteristics of many substances that we use daily. Acidic things taste sour. Basic or alkaline things taste soapy. Strong acids are corrosive and strong bases are caustic; both can cause severe skin damage that feels like a burn. However, mild acids and bases are common and relatively harmless to us. What makes a substance acidic or basic? The following equation is a good place to start:
2 H2O ⇌ 1 H3O+ + 1 OH-
We begin with two water molecules, and move some hydrogen atoms around. One water molecule gains a hydrogen and therefore takes on a positive charge, while the other water molecule loses a hydrogen atom and therefore becomes negatively charged. H3O+ is called a hydronium ion, and it makes things acidic. OH- is called a hydroxyl ion and it makes things basic. However, in water, there is a balance between hydroniums and hydroxyls so they cancel each others' charges. Pure water is neither acidic or basic; it is neutral.
So how does something become acidic or basic? That happens when the hydroniums and the hydroxyls are out of balance. If there are more positively charged hydroniums than negatively charged hydroxyls, then the substance is acidic. If there are more negatively charged hydroxyls than positively charged hydroniums, then the substance becomes basic. pH actually stands for the "potential (or power) of hydrogen."
Note: Sometimes people write H+ as a shorthand for H3O+ and that can cause confusion, because sometimes when people write H+ they really do mean only H+ and not H3O+. Watch out for that, and ask for clarification!
When we dissolve acids in water, we create an excess of hydroniums. When we dissolve bases in water, we create an excess of hydroxyls. Here are two examples. Vinegar, a weak acid, has a chemical formula of CH3COOH. When dissolved in water, it becomes CH3COO- and H+. The H+ ions combine with water molecules to form H3O+ so the solution becomes acidic. Now let's look at lye, a strong base with the chemical formula NaOH (sodium hydroxide). If we add NaOH to water, it dissociates into Na+ and OH-. The sodiums don't do anything important, but the hydroxyls make the solution more basic.
One last question: Why are strong acids and strong bases so nasty? It's because they are out of balance. They either have too many positive charges and are looking for negatives to get back into balance, or they have too many negative charges and are looking for positives to get back into balance. This makes them very reactive with anything they contact. When the positives and negatives are in equal number, they neutralize each other
The cell is the basic unit of life
and _____________________ in all organisms.
Which statements are true of heterogeneous mixtures? check all that apply. they settle out. they exhibit the tyndall effect. their solutes and solvents appear as one. they exhibit brownian motion. they are evenly distributed mixtures.
The statements which are true about heterogeneous mixtures are they settle out, they exhibit the tyndall effect and they exhibit brownian motion.
What are heterogeneous mixtures?Heterogeneous mixtures are those mixtures in which composition of their constituent partiles are not identical or even, they may vary place to place.
In the heterogeneous mixtures, solutes are present unevenly in the solution and this uneven arrangement is also arises the brownian motion means the randon motion of the particles. And these mixtures also shows the tyndall effect as light passes through the suspended particles may get scattered. On placing these mixtures without any motion for a long time, then it may sometimes settle down at the bottom.Hence, options (1), (2) & (4) are correct.
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Answer:
A,B,D
Explanation:
i got it right
How does a foam-filled winter coat help keep a person warm?
Answer:
It slows down the transfer of thermal energy from outside to inside the coat.
Explanation:
When large populations overpump aquifers, some wells can
What is common ion effect? Explain with reference to the Group 2 reagents.
The dissociation of a weaker acid can be suppressed or stopped by the addition of stronger acids which is known as common ion effect
Let's check about group || reagents
[tex]\\ \rm\rightarrowtail H_2S\longrightarrow H^++S^{2-}[/tex]
[tex]\\ \rm\rightarrowtail HCl \longrightarrow H^++Cl^-[/tex]
Here Hydrogen sulphide is neutralized by a stronger acid HCl
A microwave oven has a power rating of 850 W.
If the microwave oven is turned on for 6 minutes, how much energy will use? Give me the simplest answer possible as for a yr6-8 student to understand.. please..
Answer:
Explanation:
Before we jump into it, I just want to point out that a microwave oven has two
power ratings. One is the amount of electrical power it takes from the wall outlet to do its job. The other is the "cooking power" it delivers into the chamber in the form of microwave radiation to heat the meatloaf. The utility power required from the wall outlet is always more than the cooking power radiated into the chamber.
But we didn't really need to go into all that in order to answer the question.
1 watt = 1 joule per second
1 minute = 60 seconds
(850 watts) x (1 (joule/sec) / watt) x (60sec/min) x (6 minutes) = 306,000 joules
A sample of nitrogen gas has a pressure of 6.58 kPa at 539K. If the volume does not change, what will the pressure be at -62°C.
(I will give brainliest. Thank you so much!!)
Answer: 2.576 kPa
Explanation:
Since the volume does not change, the formula: P/T = P/T can be used.
However, all temperatures must be in kelvin, so to convert the -62 Celsius add 273 and get: 211 K.
Now, plug in to the formula: 6.58 / 539 = P / 211 → Cross multiply and then divide to get: P = 2.576 kPa :)
Answer:
the other person gets brainliest <3
Explanation:
What is incandescence? How is incandescence used to create effects with fireworks?
Answer:
Incandescence is the emission of light caused by high temperature. ... Metals, such as aluminum, magnesium, and titanium, burn very brightly and are useful for increasing the temperature of the firework. Luminescence the emission of light by a substance that has not been heated.
Explanation:
The word incandescence refer to the light produce from heat. When solution is heated it will rise up the light scale through infrared, red and the rest of the color. Fireworks is create by controlling the amount of heat which keep it in one color.
What are fireworks?Fireworks are a class of low explosive pyrotechnic device used for aesthetics and entertainment purpose.
They are commonly used in displays, combining a large number of devices in an outdoor setting.
With increase in sound level it can lead to restlessness, temporary or permanent hearing loss, high blood pressure and sleep disturbance.
Fireworks can also cause respiratory problems such as chronic or allergic bronchitis, asthma etc.
Fireworks release a fine cloud of smoke and particulate matter affecting local area quality.
Thus, the word incandescence refer to the light produce from heat. Fireworks is create by controlling the amount of heat which keep it in one color.
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The genotype is
the amount of each protein that is contained within a cell.
the observable characteristics due to the genes that are present in the cell.
the specific combination of genes contained within the cell.
the combination of a cell's environment and experiences.
Answer:
the specific combination of genes contained within the cell.
Explanation:
ex: AaBg
Do you think it's possible for a renewable resource such as water to become depleted or
reach near depletion? Explain.
The molar mass of carbon dioxide is 44.0 g/mol. How many moles of CO2 are present in a 58.4 gram sample of CO2
Answer:
1.33 moles CO2
Explanation:
The number you are converting is 58.4 g CO2, so you start with this value. The conversion factor is 44.0 g/mol CO2. In order to cross out the grams, the grams must go on the bottom of the conversion factor.
1 mol CO2
58.4 g CO2 x -------------------------- = 1.33 moles CO2
44.0 grams
The answer has three sig figs.
What number of moles of O2(g) is required to react with 3.6 mol SO2(g) in the following
reaction?
2SO2(g)+ O2(g) → →2SO3(g)
Answer:
first balance the equation:
2SO2+O2=2SO3. BALANCED EQUATION
find the ratio:
2:1:2. SO2:O2:SO3
5.0 moles of SO2 React
1/2×5.0 moles=2.5moles of O2 are needed
The 1.8 moles of the oxygen (O₂) gas are required to react with 3.6 mol SO₂(g).
What is the balanced chemical equation?A chemical equation is a way to represent a chemical reaction in terms of chemical symbols of the reactants and products. The equation in which the number of atoms of chemical substances (reactants and products) is equal on either side of the equation is known as a balanced chemical equation.
Balancing of a chemical equation must follow the law of conservation of mass. The total mass of the elements present on the reactant side must be equal to the total mass of elements present on the product side while obeying this law in a balanced chemical equation.
Given, the chemical equation of the formation of sulphur trioxide is:
2SO₂(g) + O₂(g) → 2SO₃(g)
From the above equation, we can say that the two moles of sulphur dioxide react with one mole of oxygen gas to form two moles of sulphur trioxide gas.
3.6 moles of the SO₂(g) react with moles of oxygen gas = 3.6/2 = 1.8 mol
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