Answer: B is correct.
Explanation:
Answer A is a chemical change because of intense changes of color and expansion.
Answer C is a chemical change, as hydrogen and water are chemically bonding together.
Answer D is a chemical change because oxidation involves loss of electrons during a chemical reaction.
On the other hand, melting is a physical change. Therefore, answer B is the correct answer.
A classroom has one triple-beam balance. To complete an experiment, each student must use the balance for 6 minutes. The class meets for 1 hour. How many students can participate in the experiment?
As the class is of 1 hour and and each student uses for 6 minutes so in 1 hour 10 students will use the balance.
What is a balance?
A scale or balance is a device used to measure weight or mass. These are also known as mass scales, weight scales, mass balances, and weight balances.
The traditional scale consists of two plates or bowls suspended at equal distances from a fulcrum. One plate holds an object of unknown mass (or weight), while known masses are added to the other plate until static equilibrium is achieved and the plates level off, which happens when the masses on the two plates are equal.
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If the lungs of a child hold 0.11 mol of air in a volume of 2.8 L, then the lungs of an average female adult, with a volume is 4.6 L, can be expected to hold 0.18 mol of air.
show work
Answer:
Explanation:
A childs lung can hold .11mols/ per 2.8 L so that gives us a molarity of .039M
A adults lungs can hold .18 mols /per 4.6 so that gives us .039M aswell meaining that the lung capacity between the two is not different.
A dairy is mainly involved in the operations of bottling of milk, making ice-cream and limited production of cheese. Calculate the BOD produced per 1000kg of milk processed and its population equivalent from the following data;
Quantity of milk processed daily=150000kg Waste water produced daily =240m3 BOO of waste water =1400mg/I Population equivalent per capita per day of 5-days BOD at 20C°=75g
Answer:
BOD produced per 1000kg of milk processed = (1400mg/I x 240m3) / 150000kg = 0.192mg/I
Population equivalent = (0.192mg/I x 75g) / 5 = 0.576g
Explanation:
I need help with how to do question c, d, and e
The answer of the following question of concentration are:
c) The law expression for this reaction is k[A].
d) The value of k including its units is on the specific reaction.
e) The half-life of the reaction is T1/2 = 0.693/k.
What is concentration?
Concentration in chemistry is a measure of the amount of a substance that is present in a given volume. It is usually expressed in terms of mass, moles, or volume.
c) The law expression for this reaction is rate = k[A], where k is the rate constant. This is because in a first-order reaction, the rate of reaction is proportional to the concentration of the reactant.
d) The value of k depends on the specific reaction, and can be determined by measuring the reaction rate at different concentrations of A and plotting a graph of rate versus concentration of A.
e) The half-life of a first-order reaction is given by T1/2 = 0.693/k, where T1/2 is the half-life and k is the rate constant. The units of the half-life are seconds.
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When compared to the keto form, the enol form of which of the following compounds is most stable?
1
II
III
IV
V
Which compound's? H is the least acidic?
nitroethane
propanenitrile
propanal
N,N-dimethylacetamide
acetone
Rank the compounds from strongest acids to weakest. To rank items as equivalent, overlap them.
To solve this we must be knowing each and every concept related to tautomerization. Therefore, out of keto and enol form, keto form is mot stable.
What is tautomerization?Tautomers are two structural isomers that are readily inconvertible and vary in the relative locations of their atoms while being in dynamic equilibrium. Tautomers essentially function as structural isomers.
Tautomerization is the term used to describe the tautomerization phenomena. Tautomerization includes the exchange of protons and electrons between molecules. Out of keto and enol form, keto form is mot stable.
Therefore, out of keto and enol form, keto form is mot stable.
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A solution is prepared by dissolving 51 g of salt in 340 g of
water. What is the mass percent of salt?
Answer:
okķkkkkkkkkkkkkkkkkkkkkk.I don't know the answer. GIVE THANKS
Match the time frame listed on the left with the characteristic listed on the
right.
Mesozoic era
?
Age of the dinosaurs
End of the
Mesozoic era
?
Most of Earth a desert
End of the
Paleozoic era
?
2
A layer of iridium
deposited all over Earth
mesozoic era - age of the dinosaurs
end of the paleozoic era - most of earth a desert
end of the mesozoic era - a layer of iridium deposited all over earth
The time frame can be matched with characteristic as:
mesozoic era (age of the dinosaurs) paleozoic era (desert)end of the mesozoic era (layer of iridium)What is matching?Matching is the placing of terms with their meaning or their best fit.
From the question, we can see that mesozoic era was associated with age of the dinosaurs, and paleozoic era is associated with earth in desert.
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Osmosis.
10 % solution of sodium chloride is on the first side of the semipermeable membrane separating the vessel and 2 % solution of sodium chloride is on its other side. Describe the process taking place there.
Answer:
Osmosis is taking place in the vessel, where a 10% solution of sodium chloride is on one side of the semipermeable membrane and a 2% solution of sodium chloride is on the other side. Osmosis is a special case of diffusion, where water moves from an area of higher concentration to one of lower concentration. In this case, water will move from the 10% solution to the 2% solution, as it has a higher solute concentration. This process is known as osmoregulation and it involves maintaining salt and water balance across membranes within the body’s fluids. The key to remember about osmosis is that water flows from the solution with the lower solute concentration into the solution with higher solute concentration. As such, in this case, water will flow from the 2% solution to the 10% solution.
Explanation:
help me i need it asap
Which example is a biotic factor of an aquarium ecosystem?
plastic plants placed in the gravel
algae growing on the glass
rock structure
gravel on the bottom of the aquarium
Which examples are an abiotic factor of an aquarium ecosystem? Select all that apply.
rock structure
temperature of the water
amount of algae on the glass
number of fish
Which example describes an abiotic factor interacting with a biotic factor?
The temperature of the air affecting the wind direction
Water eroding a rock
Cows eating nearby grass
The amount of sunlight affecting the growth of a plant.
Students in Ms. Brown's class are making observations in the garden outside of the school. They make a list of all the abiotic and biotic factors in their notebook. Part of the list is below:
Gravel
Grass
Butterfly
Sunflower
Bird feeder
Flowerpots
Which items on the list are a part of the garden ecosystem?
Grass, butterfly, sunflower
None of the listed items are a part of the ecosystem
All the listed items are part of the ecosystem
Gravel, bird feeder, flowerpots
The biotic factor of an aquarium ecosystem is algae growing on the glass.
The abiotic factors of an aquarium ecosystem are rock structure, temperature of the water, and amount of sunlight.
The example that describes an abiotic factor interacting with a biotic factor is the amount of sunlight affecting the growth of a plant.
All the listed items in Ms. Brown's class, including gravel, grass, butterfly, sunflower, bird feeder, and flowerpots, are a part of the garden ecosystem.
What is an ecosystem?An ecosystem is a community of living organisms (biotic factors) interacting with each other and with their physical environment (abiotic factors) in a specific area. It includes all the living and non-living components of the environment that interact with each other. Examples of ecosystems include a coral reef, a forest, a desert, and even an aquarium or a garden. Ecosystems can be large or small and can be found on land or in water. They are essential for the survival of living organisms as they provide food, shelter, and other resources necessary for life.
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an object can be considered in motion when it changes only it's direction. true or false?
Answer:
Its false Because it does'snt only show directions and changes there are others too.
Explanation:
hope it helps!!
Answer:
false
Explanation:
it's false because it's in motion
how does the name of CaS
differ from the name of CdS?
Answer:
Ca is calcium
Cd is cadmium
Ca in Grp 2
Cd is transition metal
...
Within an ecosystem,there are levels of organization. Which levels are missing from the diagram below?
Answer:
the missing levels are "population, community"
Calculate the % dissociation of 0.10 M solution of acetic acid (pKa = 4.75)
Given :
Molarity of acetic acid solution, M = 0.10 M.
pKa of acetic acid, pKa = 4.75 .
To Find :
Percentage dissociation of 0.10 M solution of acetic acid.
Solution :
We know, [tex]pK_a = -log\ K_a[/tex]
Taking antilog both side, we get :
[tex]K_a = 1.78\times 10^{-5}[/tex]
Since, acetic acid has 1 hydrogen atom to loose , so it is a monoprotic acid.
Now, percentage dissociation of monoprotic acid is given by :
[tex]\alpha = \sqrt{\dfrac{K_a}{C}}\\\\\alpha =\sqrt{ \dfrac{1.78\times 10^{-5}}{0.1}}\\\\\alpha = 0.0133\times 100 = 1.33 \%[/tex]
Hence, this is the required solution.
Plz help me : 4.lodine, (two iodine atoms bonded together) is made up of:
all metals
all nonmetals
metal and nonmetal
Answer:
all non metals
Explanation:
iodine is a non metal, and if a metal had bonded with it, it would he considered a metal and non metal. But since two iodine atoms are bonded together, they are both non metals ( I2)
Constant Volume
A 10.0L sample of gas in a rigid container at 1.00 atom and 200K is heated to
800K. Assuming that volume remains constant, what is the new pressure of the gas?
After
Can someone help me please
According to the question the new pressure of the gas is: 6.5512 kPa
What is pressure?
Pressure is the force applied to a surface divided by the area of the surface on which the force is applied. It is measured in units of force per unit area, such as pounds per square inch (psi) or pascals (Pa). Pressure can be caused by a variety of factors, such as the weight of air, the weight of a liquid, or the force of a gas. Pressure is an important concept in many fields, including physics, engineering, and chemistry.
The ideal gas law can be used to determine the gas's new pressure:
PV = nRT
where R is the universal gas constant, n is the number of moles, P is the pressure, V is the volume, and T is the temperature.
We know that V = 10.0L, n = 1.00 mole, R = 8.314 J/molK, and T = 800K.
As a result, the gas's new pressure is:
P = (1.00 mol * 8.314 J/molK * 800K) / 10.0L = 6.5512 kPa
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Thomas collected the data in Table 1 to answer a statistical question. Which statistical question does the data in Table 1 answer?
Answer:
how tall each sibling is
Explanation:
bc it says height
You have used 310 L of distilled water for a dialysis patient. How many gallons of water is that?
Answer:
82 gallons
Explanation:
There are 3.785 liters in one gallon. In order to get the amount of gallons, divide the amount of liters by 3.785.
310 L ÷ 3.785 L/gal = 81.89 gallons ≈ 82 gallons
What is the volume of 3.00 M sulfuric aid that contain 9.809 g of H2SO4 (98.09g/mol)
Answer:
[tex]V=0.0333L=33.3 mL[/tex]
Explanation:
Hello there!
In this case, according to the given information, it is necessary for us remember that the molarity is calculated by dividing the moles by the volume of the solution in liters so the volume is calculated by dividing moles by the given molarity. However, we first need to calculate the mole given the mass and molar mass of the solute, H2SO4:
[tex]n=\frac{9.809g}{98.09g/mol}=0.1mol[/tex]
Thus, the volume turns out:
[tex]V=\frac{0.1mol}{3.00mol/L}\\\\V=0.0333L=33.3 mL[/tex]
Regards!
Depression in freezing point of non-electrolyte solution containing 29.5 g of a substance in 100 g of water is 1.6 K. Determine the molar weight of the substance. (Cryometry).
The depression in freezing point of the electrolyte is 1.6 K. The weight of the solute added is 29.5 g. Then the molar mass of the compound is obtained to be 342.93 g/mol.
What is depression in freezing point?Addition of a non-volatile solute into a solvent decreases the freezing point of the solution. The depression in freezing point is calculated as follows:
ΔT = W₂ 1000 Kf / (M W₁)
where W₂ be the mass of solute and W₁ is that of solvent, Kf is called molal depression constant. M be the molar mass of the solute.
Given ΔT = 1.6 K
W₂ = 29.5 g
W₁ = 100 g
Kf of water = 1.86 K/m
Then M = W₂ 1000 Kf / ( ΔT W₁)
M = 29.5 g× 1000 × 1.86 / (1.6 K × 100 g) = 342.9 g/mol
Thus, the molar mass of the solute is 342.9 g/mol.
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[H3O+] = 3.6 x 10-2 M
Answer:
Explanation:
Hello there!
In this case, since this concentration of hydronium ions is given, we infer we may calculate that of the hydroxide ions, pH and pOH because no question was specifically given. That is why we proceed as follows:
- pH: Here, we use this concentration to calculate the pH according to the negative logarithm:
[tex]pH=-log(3.6x10^{-2})=1.44[/tex]
Which means that the solution is acidic as the pH is less than 7.
- pOH: since the pH added to the pOH is 14, we can calculate the latter as follows:
[tex]pOH=14-1.44=12.56[/tex]
- Hydroxide concentration: Given the pOH, we apply the antilogarithm to calculate such concentration as shown below:
[tex][OH^-]=10^{-pOH}=10^{12.56}=2.75x10^{-13}M[/tex]
Keep in mind, this is an arbitrary solution because no question was provided.
Regards!
What is the mass percent of calcium chloride if 57 g of CaCl2 is
dissolved in 334 g of water?
Answer:
Solubility in water Anhydrous: 74.5 g/100 mL (20 °C) Hexahydrate: 49.4 g/100 mL (−25 °C) 59.5 g/100 mL (0 °C) 65 g/100 mL (10 °C) 81.1 g/100 mL (25 °C) 102.2 g/100 mL (30.2 °C) α-Tetrahydrate: 90.8 g/100 mL (20 °C) 114.4 g/100 mL (40 °C) Dihydrate: 134.5 g/100 mL (60 °C) 152.4 g/100 mL (100 °C)
How many grams of silver chromate will precipitate when 250.0 mL of 0.350 M silver nitrate are added to 250.0 mL of 0.450 M potassium chromate?
Answer:
2 AgNO3(aq) + K2CrO4(aq) Ag2CrO4(s) + 2 KNO3(aq)
Explanation:
0.150 L AgNO3 0.500 moles AgNO3 1 moles Ag2CrO4 331.74 g Ag2CrO4 = 12.4 g Ag2CrO4
1 L 2 moles AgNO3 1 moles Ag2CrO4
0.100 L K2CrO4 0.400 moles K2CrO4 1 moles Ag2CrO4 331.74 g Ag2CrO4 = 13.3 g Ag2CrO4
1 L 1 moles K2CrO4 1 moles Ag2CrO4
What is an extinction event
HELP HELP URGENT
STRONG ACIDS AND BASES
Answer:
Solution A is correct.
Explanation:
Strong acids or bases are assumed to dissociate completely when in a aqueous solution.
50mL of potassium hydroxide (KOH) solution contains 7 grams of potassium hydroxide.
What is the molarity (mol/L) of the potassium hydroxide solution?
Given the atomic masses:
K= 39,0 = 16 and H= 1
Answer:
2.5 mol/L
Explanation:
We'll begin by calculating the number of mole in 7 g of KOH. This can be obtained as follow:
Mass of KOH = 7 g
Molar mass of KOH = 39 + 16 + 1
= 56 g/mol
Mole of KOH =?
Mole = mass /molar mass
Mole of KOH = 7 / 56
Mole of KOH = 0.125 mole
Next, we shall convert 50 mL to L. This can be obtained as follow:
1000 mL = 1 L
Therefore,
50 mL = 50 mL × 1 L / 1000 mL
50 mL = 0.05 L
Finally, we shall determine the molarity of the KOH solution. This can be obtained as follow:
Mole of KOH = 0.125 mole
Volume = 0.05 L
Molarity of KOH =?
Molarity = mole / Volume
Molarity of KOH = 0.125 / 0.05
Molarity of KOH = 2.5 mol/L
Thus, the molarity of the KOH solution is 2.5 mol/L
Put the levels of ecosystems in order from smallest to largest:
ecosystem, community, individual, population
Reorder answers
1.population
2.ecosystem
3.individual
4.community
Standard temperature and
pressure (STP) is 273 Kand
[?] atm.
Answer:
Explanation:
273K
1ATM
Answer:
273 K 1 atm
Explanation:
Standard temperature and pressure (STP) is [273] K and [1] atm
A certain compound consists of 54.53% C, 9.15% H, and 36.32% O by mass. The molar mass of the compound is 88.10g/mol, What is the molecular formula of this compound?
The compound is going to have the molecular formula; [tex]C_{4} H_{8}O_{2}[/tex]
What is the molecular formula?We know that the molecular formula is the formula of the compound that shows the number of the atoms of each of the elements that we can be able to find in the compound.
Now for the compound that we have, we divide through by the relative atomic mass of each;
C - 54.53/12 H - 9.15/1 O - 36.32/16
C - 4.5 H - 9.15 O - 2.27
Dividing through by the lowest ratio;
C - 4.5/2.27 H - 9.15/2.27 O - 2.27/2.27
C - 2 H - 4 O -1
The empirical formula is [tex]C_{2} H_{4} O[/tex]
We now have;
[2(12) + 4(1) + 16] n= 88.1
n = 88.1/44
n = 2
The molecular formula is;
[tex]C_{4} H_{8}O_{2}[/tex]
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state types of environment pollution?
Answer:
Air Pollution.
Water Pollution.
Soil/Land Pollution.
Noise Pollution.
Radioactive Pollution.
Explanation:
What is an electrolyte?
a
A-Any type of substance
A salt
A substance that cannot conduct electricity in solution
A substance that can conduct electricity in solution
с
d
Answer:
A substance that can conduct electricity in solution