Pls help ASAP it’s timing meeee!!!!!
Which statement describes the best way to determine how different levels of light affect the growth of seedling plants?
Choose three different light levels, and place four identical plants under each light level to observe the light’s effect on multiple plants.
Choose five different light levels, and place one identical plant under each of the light levels for exactly one week.
Choose four different light levels, and place eight different plant types under the light levels, two under each one, and observe them every day.
Choose one type of light and one type of plant, and then observe the plant for at least four weeks, measuring it each day.
Answer:
Choose three different light levels, and place four identical plants under each light level to observe the light’s effect on multiple plants.
Explanation:
I need to know what the question is asking please help
Answer: What events create the heaviest elements?
I would Select:
Neutron Star Collissions
Supernova
what characteristics of a metallic bond explains some of the properties of metals
Answer:
See Explanation
Explanation:
Metallic bonds involve attraction between electrons and positively charged metal ions. The metals are ionized and electrons form a sea of valence electrons. These loosely bound electrons surround the nuclei of the metals.
The presence of this sea of electrons explains the fact that metals conduct electricity and heat due to the free valence electrons.
Due to the nature of the bonding between metal atoms,metals are malleable and ductile.
Due to the strong electrostatic interaction between metal ions and electrons, the metallic bond is very strong and is very difficult to break thereby accounting for the greater strength of metals as the size of the metallic ion decreases.
A scientist observes the cells of a newly discovered animal under a
microscope. Which of the following cell parts is the scientist likely to find?
A. Cell membrane, chloroplasts, and a nucleus
B. Cell wall, cell membrane, and ribosomes
O C. Cell wall, chloroplasts, and lysosomes
D. Cell membrane, ribosomes, and a nucleus
Answer:
D
Explanation:
The rest have characteristics of a plant cell
g A student determines the number of moles of water in a hydrated metal oxide by weighing a clean, dry crucible and lid while the crucible is empty, then reweighing the crucible and lid with a sample of the hydrate, heating the crucible and lid with a Bunsen burner and then reweighing the crucible and lid with the sample after cooling to room temperature. Which error will result in too high a value for the amount of water of hydration
The question is incomplete, the complete question is;
A student determines the number of moles of water in a
hydrated metal oxide by weighing a clean, dry crucible
and lid while the crucible is empty, then reweighing the
crucible and lid with a sample of the hydrate, heating the
crucible and lid with a Bunsen burner and then
reweighing the crucible and lid with the sample after
cooling to room temperature. Which error will result in
too high a value for the amount of water of hydration?
(A) The heating is conducted only once instead of the
three times recommended by the procedure.
(B) The lid is left off the crucible when it is weighed
with the hydrated oxide.
(C) The metal oxide reacts partially with oxygen in the
air, forming a compound in a higher oxidation state.
(D) Some of the heated oxide is spilled from the crucible
before it can be weighed.
Answer:
(D) Some of the heated oxide is spilled from the crucible
before it can be weighed.
Explanation:
It is possible to determine the number of moles of water in a hydrated metal oxide by weighing a clean, dry crucible and lid while the crucible is empty, then reweighing the crucible and lid with a sample of the hydrate. The crucible and lid with the sample are heated, cooled and reweighed.
As this process is going on, suppose some of the heated oxide is spilled from the crucible, then the mass of heated or anhydrous oxide decreases leading to a consequent increase in the number of moles of water in the hydrated metal oxide, hence the answer above.
The too high a value for the amount of water of hydration error is occur due to heating of given hydrated sample.
What is hydrated compounds?
Hydrated compounds are those compounds in which water molecule is present with the normal compound.
To get the correct value of weight of hydrated compound, first we have to weigh the empty crucible and lid and then with sample of compound in the crucible and lid. After this substract empty weigh of crucible & lid from the sample-crucible-lid weigh. If we substract the weigh from heated sample crucible and lid, then we get the error because the hydrated water molecule may decompose due to heating and moles of water increases.
Hence, error will occur if we heat the sample.
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What will change more solid NiCl2 is added
Select the correct answer.
What is the molecularity of this elementary step?
A+ A+B-->C+D
A.
unimolecular
B.
bimolecular
c.
trimolecular
D.
tetramolecular
Answer: C not really sure thoo
If 7.4 moles of carbon dioxide is produced in this reaction, how many moles of oxygen gas would be needed?
1 C7H16 + 11 O2 = 7 CO2 + 8 H2O
Answer:
11.6 mol O₂
Explanation:
C₇H₁₆ + 11 O₂ → 7 CO₂ + 8 H₂OIn order to solve this problem we need to convert moles of carbon dioxide (CO₂) into moles of oxygen gas (O₂). To do so we'll use a conversion factor containing the stoichiometric coefficients of the balanced reaction:
7.4 mol CO₂ * [tex]\frac{11molO_2}{7molCO_2}[/tex] = 11.6 mol O₂Please someone answer this asap
Answer:
b or c but I would just pick c
Answer:
C
Explanation:
Sun is an energy source not a matter.
Consider the following data on some weak acids and weak bases:
acid base
name formula Ka name formula Kb
hydrocyanic acid HCN 4.9 x 10^-10 hydroxylamine HONH2 1.1 x 10^-1
hypochlorous acid HCIA 3.0 x 10^-18 ethylamine C2H5NH2 6.4 x 10^-4
Use this data to rank the following solutions in order of increasing pH. In other words, select a '' next to the solution that will have the lowest pH, a '' next to the solution that will have the next lowest pH, and so on.
a. 0.1 M HONH3Br
b. 0.1 M NaNO3
c. 0.1 M C2H5NH3Cl
d. 0.1 M NaF
Answer:
a < c < b < d
Explanation:
The weak acid with the lowest pKa will be the most acidic. In the other way, the conjugate base which the acid is weakest will be strongest.
The weak base with the lowest pKb will be the most basic. And the conjugate base of the weakest base will be a strongest acid.
Using the values:
Ka HCN = 4.9x10⁻¹⁰
Kb HONH2 = 1.1x10⁻⁸
Ka HClA 3.0x10⁻⁸
Kb C2H5NH2 = 6.4x10⁻⁴
The NaNO3 is the conjugate base of a strong acid as HNO3. That means its solutions are almost neutral
The HONH3Br is the conjugate acid of a weak base. Its solutions will be acidics
C2H5NH3Cl is the conjugate acid of a weak base as ethylamine, its solutions will be acidic.
As ethylamine has a lower pkb than hydroxylamine, the conjugate acid of hydroxylamine will be more acidic.
NaF is the conjugate base of a weak acid as HF. Its solutions will be basics
The order in increasing pH is:
HONH3Br < C2H5NH3Cl < NaNO3 < NaF
a < c < b < dHow many Liters are in 98.2 moles of neon?
Answer:
2200 L
Explanation:
There are 22.4 L in 1 mole of neon so if you have 98.2 L, then you have 98.2 mole x (22.4 L/mole) = 2200 L of neon.
How does publishing in scientific journals help ensure that science leads to
reliable results?
A. It allows results to be reviewed and reproduced by other
scientists.
B. It allows the public to decide if science is worthwhile.
C. It shows which experiments are the most popular with scientists.
D. It gives scientists a reason to do more experiments.
Answer:
A. it allows results to be reviewed and reproduced by other scientists.
When 15. 3 g NaCl reacts with 81.70 g Pb(NO3)2, sodium chloride is the limiting reactant, according to the balanced equation below. How many grams of lead (II) nitrate will remain after the reaction stops?
2 NaCl + 1 Pb(NO3)2 → 2 NaNO3 + 1 PbCl2
Answer:
[tex]m_{Pb(NO_3)_2}^{leftover}=38.34g[/tex]
Explanation:
Hello there!
In this case, given the chemical reaction by which the sodium chloride reacts with lead (II) nitrate and the former is the limiting reactant, it is possible to calculate the mass of lead (II) nitrate that are actually consumed according to the 2:1 mole ratio between them:
[tex]m_{Pb(NO_3)_2}=15.3gNaCl*\frac{1molNaCl}{58.44gNaCl}*\frac{1molPb(NO_3)_2}{2molNaCl} *\frac{331.21gPb(NO_3)_2}{1molPb(NO_3)_2} \\\\m_{Pb(NO_3)_2}=43.36gPb(NO_3)_2[/tex]
Thus, the leftover of lead (II) nitrate is:
[tex]m_{Pb(NO_3)_2}^{leftover}=81.70g-43.36g\\\\m_{Pb(NO_3)_2}^{leftover}=38.34g[/tex]
Best regards!
How many liters would you need to make a 0.8 M solution with 20 grams of lithium chloride?
Answer:
0.5875L
Explanation:
concentration = mole/ volume
n(LiCl) = 20 / (7 + 35.5) = 0.47 mol
volume = mole / conc.
volume = 0.47 /0.8
= 0.5875 dm³ = 0.5875L
A saline solution, NaCl in water, is 0.92 % (m/v). How many grams of NaCl are required to prepare 35.0 mL of this solution?
Answer:
0.322 g
Explanation:
Since our concentration is given in mass per volume percent % (m/v)
% (m/v) = mass of solute in g/volume of solution in mL × 100%
Since % (m/v) = 0.92 and volume of the required solution is 35.0 mL, we find the mass of NaCl from
mass of NaCl = % (m/v)/100 % × volume of solution
= 0.92 % (m/v)/100 %× 35 mL
= 0.0092 × 35
= 0.322 g
The study of a chemical is called chemistry.
The correct answer is 0.322 g
The saline is said that the amount of salt present in the solution. The formula used to solve the question is as follows:-
[tex]\frac{m}{v} = \frac{mass \ of\ solute}{volume\ of\ solution} * 100[/tex]
The data is given as follows:-
0.92 %(m/v)Volume is 35.0 mL,Mass of NaCl is as follows:-
[tex]\frac{0.92}{100} * 35 mL[/tex]
[tex]0.0092 * 35\\= 0.322 g[/tex]
Hence, the correct answer is 0.322g.
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What is the energy of a photon?
A. A photon has no energy.
B. The energy of a photon is hxc.
c. The energy of a photon is hx 2.
D. The energy of a photon is h* f.
Terry, a student, performs a titration. He completes these steps as part of his titration procedure: 1. He cleans and rinses a burette with standardized base. 2. He fills the burette with standardized base solution. 3. He reads and records the initial burette volume. 4. He adds a base from the burette to an acid. 5. He observes a color change in the Erlenmeyer flask. 6. He stops the addition of base from the burette. 7. He reads and records the final burette volume. Which steps will provide information needed to calculate the volume of base needed to reach the equivalence point? A. 1 and 6 B. 3 and 7 C. 3, 4, and 6 D. 1, 2, and 7
Answer:
D
Explanation:
D is the answer because 2 is needed to know
Answer:
B) 3 and 7
Explanation:
i just took the test
Calculate the final concentration of each of the following:
2.0 L of a 6.0 M HCl solution is added to water so that the final volume is 6.0 L
--
Water is added to 0.50 L of a 12 M NaOH solution to make a 3.0 L of a diluted NaOH solution
Answer:
1. 2 M
2. 2 M
Explanation:
1. Determination of the final concentration.
Initial Volume (V₁) = 2 L
Initial concentration (C₁) = 6 M
Final volume (V₂) = 6 L
Final concentration (C₂) =?
The final concentration can be obtained as follow:
C₁V₁ = C₂V₂
6 × 2 = C₂ × 6
12 = C₂ × 6
Divide both side by 6
C₂ = 12 / 6
C₂ = 2 M
Therefore, the final concentration of the solution is 2 M
2. Determination of the final concentration.
Initial Volume (V₁) = 0.5 L
Initial concentration (C₁) = 12 M
Final volume (V₂) = 3 L
Final concentration (C₂) =?
The final concentration can be obtained as follow:
C₁V₁ = C₂V₂
12 × 0.5 = C₂ × 3
6 = C₂ × 3
Divide both side by 3
C₂ = 6 / 3
C₂ = 2 M
Therefore, the final concentration of the solution is 2 M
Which of the following accurately describes the function of the muscular
system?
O A. To prevent and fight disease
B. To provide support for the body
C. To get rid of wastes and excess water
D. To allow the body to move
what happens to gas molecules as the pressure is increased while the temperature and volume of the container remain constant according to the kinetic molecular theory
Answer:
According to the kinetic molecular theory of gases, the average speed and kinetic energy of gas molecules would INCREASE.
Explanation:
In the kinetic molecular theory of gases, assumptions were made based on macroscopic properties of gas (pressure, volume and temperature) which are as a result of the microscopic properties like the position and the speed of the gas molecules. The kinetic molecular theory explains the behaviour of gases through the following 5 assumptions made about an ideal gas;
--> Molecules of a gas are in constant and rapid motion in straight lines until they collide with one another and with the walls of their containers.
--> The actual volume occupied by the had is negligible compared with the volume of the container.
--> Forces of attraction or repulsion between the molecules of a gas are negligible
--> The collision between the molecules is perfectly elastic.
--> The average kinetic energy of the gas molecules is proportional to the temperature of the gas.
Because gas molecules are in constant motion, it has kinetic energy which can be altered when there is increase in pressure. An increase in pressure will cause gas molecules to collide more frequently with one another. This in turn leads to increase in average speed and the kinetic energy of the individual molecules.
Describe the effects lenses have on light and their possible technological applications.
Answer:
lenses is used to refract light inward or outward
there are two type of lenses. Concave and convex lense
Convex lense converge ray of light
Concave lense diverge ray of light
useful application =:
=> camera
=> flashlight
=> lasers
=> Binoculars and Telescope
hope it helps
Answer:
Explanation:
Lenses are made of glass or other transparent materials for light. They are optically dense so light slows down on entering it. It is called refraction which bends the light on entering and leaving the lenses.
Refraction by lenses can be used for all kinds of optical applications, e.g. camera, telescope, magnifying glasses, solar heating.
करताह!
गर्मियों में घड़े का जल ठंडा क्यों होता है?
Answer:
I don't understand the question
Explanation:
what is your name
You have a cold gas of atoms, and you observe that if you shine light consisting of photons with energy 10 eV through the gas, some free electrons are observed, implying that a photon of this energy is able to ionize an atom in the gas. (a) If you find that the emitted electrons from the gas have a kinetic energy of 1 eV, what is the ionization energy of the cold atom
Answer:
Ionization Energy = 9 eV
Explanation:
If we apply the law of conservation of energy to the given situation, we will get the following equation:
[tex]Energy\ of\ Photon = Ionization\ Energy + Kinetic\ Energy\ of\ Electron\\[/tex]
where,
Energy of Photon = 10 eV
Ionization Energy = ?
Kinetic Energy of Electrons = 1 eV
Therefore,
[tex]10\ eV = Ionization\ Energy + 1\ eV\\Ionization\ Energy = 10\ eV - 1\ eV[/tex]
Ionization Energy = 9 eV
A chemistry student heated 2.255 g of oxygen gas in the presence of 5.145
Answer:
a
Explanation:
classify each of the following reactions when only the reactants are given and fill in the products.
explain your answer for brainliest.
Answer:
CO2 + MgO
Explanation:
We want the number of each element on the Reactants (Left side) to be equal to the number of each element on the Product side (Right side).
What is the Same about carbohydrates, proteins , and fats ?
Answer:
The main similarity between carbohydrates, proteins and fats is that they are all used for energy.
Explanation:
I hope this helps, have a blessed day.
My swimming pool is rectangular (16 feet by 34 feet) and has a depth of 6 feet. Lets imagine that my pool water is full to the top and is heated by a laser that emits photons with a wavelength of 520 nm. The starting temperature of my pool is a chilly 52 degrees Celsius. How many moles of photons would be required to heat the pool to a balmy 80 degrees Celsius
Answer:
Number of moles of photons required = 5.04 × 10⁴ moles
Explanation:
The energy of a photon can be calculated from Planck's equation E = hc/λ
Where h = 6.63 × 10-³⁴ Js and c, the velocity of light = 3.0 × 10⁸ m/s
Energy of one mole of photons = N₀ × hc/λ
wavelength of photon, λ = 520 nm = 5.20 × 10-⁷ m
Energy of one mole of photons = 6.02 × 10²³ × 6.63 × 10−³⁴ × 3 × 10⁸/5.20 × 10-⁷
Energy of one mole of photons = 2.30 × 10⁵ J/mol
Energy required to raise the temperature of a given mass of a substance, E = mcΔT
Where m is mass of substance, c is specific heat capacity, ΔT is temperature difference
Mass ofnwternin the pool = volume × density
Volume of water = Volume of swimming pool
Volume of water = 16 × 34 × 6 ft³ = 3264 ft³
1 ft³ = 28316.8 cm³; 3264 ft³ = 28316.8 × 3264 = 92426035.2 cm³
Density of water = 1 g/cm³
Mass of water = 92426035.2 cm³ × 1 g/cm³ = 92426035.2g
ΔT = 80°C - 50°C = 30°C, c = 4.18 J/g/K
Energy required to raise 92426035.2 g water by 30° C = 92426035.2 × 4.18 × 30
Energy required = 1.16 × 10¹⁰ J
Hence, number of moles of photons required = 1.16 × 10¹⁰ J/2.30 × 10⁵ J/mol
Number of moles of photons required = 5.04 × 10⁴ moles
The pressure on 200 milliliters of a gas at constant
temperature is changed from 380 torr to 760 torr. The new
volume of the gas is
answerA) 100 mL
Explanation:
At constant temperature and number of moles, Using Boyle's law
Given ,
V₁ = 200 mL
V₂ = ?
P₁ = 60 kPa
P₂ = 120 kPa
The new volume of the gas is 100mL
Boyle's law is use to calculate the volume of a gas in relation with its pressure. The Boyle's law equation is as follows:
P1V1 = P2V2
Where;
P1 = initial pressure of the gas (torr)
P2 = final pressure of the gas (torr)
V1 = initial volume of the gas (mL)
V2 = final volume of the gas (mL)
According to the information of this question, the pressure on 200mL of a gas changed from 380 torr to 760 torr. Hence;
V1 = 200mL
V2 = ?
P1 = 380torr
P2 = 760torr
Using P1V1 = P2V2
V2 = P1V1/P2
V2 = (380 × 200) ÷ 760
V2 = 76000 ÷ 760
V2 = 100mL
Hence, the new volume of the gas is 100mL
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Help please asap will mark brainliest!
Answer:
28.466256
Explanation:
