Answer:
B.
Our pupils contract and expand depending on the amount of light at any given time in order to avoid being blinded and to see better in the darkness.
Why do you think it would be important for scientists to test local water?
Answer:
It would be important because they will know if the water is infected by some type of disease or harmful bacteria
Explanation:
A 5.0 L air sample at a temperature of -50°C has a pressure of 800.00 mmHg. What
the new pressure if the temperature is raised to 100°C and the volume expands to 7.0
L?
Answer:
956 mmHg
Explanation:
The combined gas law states that P1V1/T1 = P2V2/T2 when moles of gas are constant. We're looking for P2, so solve all of that for P2. Make sure you convert your temperatures to Kelvin by adding 273 to the Celsius temperatures.
P2 = P1V1T2/T1V2
P1 = 800.00 mmHg
V1 = 5.0 L
T2 = 100 + 273 = 373 K
T1 = -50 + 273 = 223 K
V2 = 7.0 L
P2 = (800.00 mmHg)(5.0 L)(373 K) / (223 K)(7.0 K) = 956 mmHg
The combustion of coal, a fossil fuel, to produce electrical energy produces a by-product, sulfur dioxide, which is emitted into the atmosphere. Sulfur dioxide will mix with the components in the atmosphere to produce _____.
Forest Fires
Global warming
Acid Rain
Algae growing in ponds and lakes
Please write the answer in format below
Answer:
0.95 L
Explanation:
Step 1: Given data
Concentration of the Mg(NO₃)₂ solution (C): 0.32 M (0.32 mol/L)
Mass of Mg(NO₃)₂ (solute): 45 g
Step 2: Calculate the moles corresponding to 45 g of Mg(NO₃)₂
The molar mass of Mg(NO₃)₂ is 148.33 g/mol.
45 g Mg(NO₃)₂ × 1 mol Mg(NO₃)₂ /148.33 g Mg(NO₃)₂ = 0.303 mol Mg(NO₃)₂
Step 3: Calculate the volume of solution that contains 0.303 moles of Mg(NO₃)₂
The concentration of the solution is 0.32 M, that is, there are 0.32 moles of Mg(NO₃)₂ per liter of solution.
0.303 mol Mg(NO₃)₂ × 1 L Solution / 0.32 mol Mg(NO₃)₂ = 0.95 L
What would
happen to the
vultures if the
gazelle
decreased?
Answer: If the gazelle population starts to decrease this could lead to some vultures not having enough food to eat
Explanation: This explains the obvious outcome of what would happen.
Hope you do well with what your doing :)
Mark as Brainliest please :)
BRAINLIEST if answered correctly
Answer:
I would choose E
Explanation:
Chemical reactions occur when chemical bonds between atoms are formed or broken. The substances that go into a chemical reaction are called the reactants, and the substances produced at the end of the reaction are known as the products
web-
2. Given the following equation: 2 KCIO3 ---> 2 KCl + 3 O2
How many moles of O2 can be produced by letting 12.00 moles of KClO3 react?
show work. helppp asap
Answer:
18 moles of O2 can be produced by letting 12.00 moles of KClO3 react
Explanation:
The balanced equation is
2KCIO3 ---> 2 KCl + 3 O2
As per the reaction,
2 mole of KClO3 produces 3 mole of O2 gas
Hence, 12 moles of KClO3 will produce [tex]12*\frac{3}{2} =18[/tex]
Hence, 18 moles of O2 can be produced by letting 12.00 moles of KClO3 react
In which way do buffalos protect themselves from predator animals such as lions
Answer: Both males and females have sharp, curved horns extending from the sides of their heads which are used to defend themselves against predators.
Explanation:
Many diseases can be prevented with a proper diet, exercise, and abstinence from smoking, alcohol, drugs, and sexual activity. True or False( Explain)
Answer:
TrueExplanation:
This is due to multiple reasons. First of which, proper diet with a variety of selection of foods from vegetables, to dairy and meats can provide the body with essential nutrients used to fight off diseases and germs and improve the immune system. Exercise can also help boost the immune system and prevent diseases as well. It can also improve the condition of the heart which prevents heart disease and help the brain (prevent strokes). Drugs, smoking, alcohol and unsafe sexual activity can lead to a multitude of diseases, such as lung cancer, drug addictions, cardiac arrest, blood clots, HIV and other STDs, liver failure, etc. So it would be wise to abstain from those activities.
Lion 7
Which of the following is a valid science lab safety guideline?
omplete
s out of
Select one:
O a. Do not eat or drink anything while in the lab.
ag
tion
O b. Wear a drawstring hoodie to protect yourself from chemicals.
O c. Wait to clean up any spills until you complete the lab
procedure.
O d. Change the lab procedure if necessary to improve the
experiment.
Check
Answer:
A.
Explanation:
You should NEVER eat or drink anything in a lab area. You never know what chemicals or gases are in the lab, and they can harm you.
Wearing a drawstring hoodie won't protect you from chemicals.
Don't wait to clean up chemicals, immediately get a teacher and clean it up (follow the teachers instructions). You never know what has spilled, and if it is harmful or not, or if there is a certain procedure to clean it up.
Don't change the equipment in the middle of an experiment. This can tamper with your results, and depending on what you are working with, this can be dangerous.
Q3: Match the column A with Column B and write answer in Column C
Answer:
ok
Explanation:
1d
2c
3b
4a
Suspensions can be undersaturated.
O True
O False
Answer:
true
Explanation:
How many moles are in 32.8 L of CO gas at STP?
At STP, 1 mole of any gas occupies 22.4 L of space. Since we are given STP conditions here, we can use this ratio to determine the number of moles of CO gas: (32.8 L CO)/(22.4 mol CO/L CO) = 1.51 mol CO.
So, there are 1.51 moles of CO gas.
Water pollution has severely impacted animals and plants in New York's Hudson
What is the energy of an electron in a Li+ ion when an electron moves from n = 2 to n =3?
Answer:
The question wants you to determine the energy that the incoming photon must have in order to allow the electron that absorbs it to jump from
n
i
=
2
to
n
f
=
6
.
A good starting point here will be to calculate the energy of the photon emitted when the electron falls from
n
i
=
6
to
n
f
=
2
by using the Rydberg equation.
1
λ
=
R
⋅
(
1
n
2
f
−
1
n
2
i
)
Here
λ
si the wavelength of the emittted photon
R
is the Rydberg constant, equal to
1.097
⋅
10
7
m
−
1
Plug in your values to find
1
λ
=
1.097
⋅
10
7
.
m
−
1
⋅
(
1
2
2
−
1
6
2
)
1
λ
=
2.4378
⋅
10
6
.
m
−
1
This means that you have
λ
=
4.10
⋅
10
−
7
.
m
So, you know that when an electron falls from
n
i
=
6
to
n
f
=
2
, a photon of wavelength
410 nm
is emitted. This implies that in order for the electron to jump from
n
i
=
2
to
n
f
=
6
, it must absorb a photon of the same wavelength.
g Consider (12.5 A) micro-grams of a radioactive isotope with a mass number of (78 B) and a half-life of (32.6 C) million years. If energy released in each decay is 32.6 keV, determine the total energy released in joules (J) in 1 (one) year. Give your answer with three significant figures.
Answer:
Energy released = 18.985 J
Explanation:
The exponential decay of radioactive substance is given by -
N(t) = N₀ [tex]e^{-kt}[/tex]
where
N₀ = initial quantity
k = decay constant
Half life, [tex]t_{1/2} = \frac{ln 2}{k}[/tex]
⇒[tex]k = \frac{ln 2}{t_{1/2} }[/tex]
Given,
N₀ = 12.5 + 3 = 15.5 × 10⁻⁶ gm
[tex]t_{1/2}[/tex] = 32.6 + 18 = 50.6 × 10⁶ years
So,
[tex]k = \frac{ln 2}{50.6 * 10^{6} }[/tex] = 1.361 × 10⁻⁸ year⁻¹
Now,
N(1) = 15.5 × 10⁻⁶ [tex]e^{-1.361*10^{-8} *1}[/tex]
= 15.49999978904
Now,
Substance decayed = N₀ - N(t)
= 15.5 × 10⁻⁶ - 15.49999978904 × 10⁻⁶
= 21.095 × 10⁻¹⁷ kg
⇒Δm = 21.095 × 10⁻¹⁷ kg
So,
Energy released = Δmc²
= 21.095 × 10⁻¹⁷ × 3 ×10⁸ × 3 × 10⁸
= 189.855 ×10⁻¹
= 18.985 J
⇒Energy released = 18.985 J
10. Although lidocaine is marketed as its hydrochloride salt, it doesn’t exhibit the same level of physiological activity as the free amine. The free amine is more lipophilic and diffuses across a neuron cell membrane more rapidly than the ionic salt, resulting in a more rapid onset of anesthesia. Therefore, sodium bicarbonate (NaHCO3) is added to a solution of lidocaine prior to injection. How does the addition of sodium bicarbonate promote a faster anesthetic effect?
Answer:
Bicarbonate neutralizes the acidity of Lidocaine and hence reduce the pain
Explanation:
Alkalinization by addition of sodium bicarbonate causes buffering of local anesthetics and hence produce faster anesthetic effect such as pain control, pain reduction while injecting the patient and faster onset of local anesthetics.
Lidocaine along with epinephrine results into acidic compound wit respect to subcutaneous tissue. Hence, when bicarbonate is added, it neutralizes the acidity of Lidocaine and hence decrease the pain.
What transition energy corresponds to an absorption line at 502 nm?
A. 4.56 x 10-19
B. 1.76 10-19
C. 2.53 x 10-19
D. 3.96 10-19 J
Answer:
D 3.96 10-19J
Explanation:
I took the test
The_____
determines the quantity that can be produced by the reaction.
Answer:
C) limiting reagent
Explanation:
The limiting reagent is the reactant that you don't have a lot of, it will be completely used up in the reaction
1. You and a friend are hiking through a canyon. You tell your friend that the rock layers in the canyon are all different ages, and you can
tell which rock layers are the oldest and which are the youngest. She picks four different rock layers on the canyon wall, as shown in the
photograph
Which layer is the youngest?
A. Layer 1
O B. Layer 2
C. Layer 3
D. Layer 4
Answer:
its number 4 D layer 4
Explanation:
just look at it look at the colors so that's how you know and plus it just old
Answer:
From what I gathered from researching, I would say that Layer 2 is the correct answer to the question you asked.
Explanation:
The reason I'd say it is Layer 2 is because the lower you look in a canyon, the farther back you look in time. Over that canyon's history, more layers are added on top of the rock and ground as erosion and weathering happen.
Layer 2 is the highest up, which means that it was added the most recent of the other layers. Although there are more things that could maybe be taken to account, the best answer I see from what information you were given in this question... Layer 2 is the correct answer.
Hope that helps!
Question 3
Which of the objects on the shelf has the greatest inertia?
10 kg
5 kg
2kg
a
b
2 kg
5 kg
10 kg
С
d
The all have the same inertia
HELP PLEASEEEEEE ASAP
A condition in which bones become weak and brittle.
The body constantly absorbs and replaces bone tissue. With osteoporosis, new bone creation doesn't keep up with old bone removal.
thus 2) is correct.
a disease in which bone tissue becomes breakable and thin.
if it helps don't forget to like and Mark me
PLEASE HELPP!
a 55g block of metal has a specific heat of 0.45 J/g°C. What will be the temperature change of this metal if 450 J of heat energy are added?
Answer:
18.18 C
Explanation:
m=55
C=0.45
Q=450zj
ch.temp=?
Q=mct
450 = (55)(.45)T
450 = 24.75
/24.75 = /24.75 (cancels out)
18.18 is the answer
The three elements in the photos all belong to the same group, or column, of the periodic table. These elements all produce salts when they react
with metals. What are some differences between these elements?
Choose all that apply.
Answer:
The answer is Color,atomic mass, state of matter of each element.
Explanation:
how many moles are there in 2.20 x 10^23 molecules of Na2SO4
Answer:
Explanation:
450 grams of Na2SO4? 450 Na soullnol Na2SO4 16.02x1023 molec, Na₂SO4 = 119x1024. | 142.05g Na25041 Imol Naz
2) A balloon was inflated to a volume of 5.0 liters at a temperature of
7.0°C. It landed in an oven and was heated to 147°C. What is its new
volume?
Answer:
6.12 L
Explanation:
Given that,
Initial volume, V₁ = 5 L
Initial temperature, T₁ = 7.0°C = 343 K
Final temperature, T₂ = 147°C = 420 K
We need to find its new volume. The relation between volume and temperature is given by :
[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\\\\V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{5\times 420}{343}\\\\V_2=6.12\ L[/tex]
So, the new volume is 6.12 L.
i really need help with this
Answer:
i hope i can help you with this
Answer: focus in class
Explanation:
:////
See if you can complete the following table using only what is on this page. Hint. Two of the entries are for the same element.
Element
Symbol
Nuclear
Symbol
Atomic Mass
Protons Neutrons
Electrons in
Number Number
Neutral Atom
57
82
138
57
ola
Fe
59
26
Answer and Explanation:
The empty spaces should be completed step-by-step as follows:
First line:
Element symbol: La (it is the corresponding element for the atomic number 57)
Mass number = Atomic number + Neutrons = 57 + 82 = 139
Nuclear symbol: ¹³⁹₅₇ La because the atomic number is 57 and mass number is 139.
Protons: 57 (is equal to the atomic number for a neutral atom)
Electrons in neutral atom = Atomic number = 57
Second line:
Element symbol: La (it is the corresponding element for the atomic number 57 and mass number 138)
Atomic number: 57 (from the Periodic Table, for La)
Mass number = 138 (from the nuclear symbol)
Protons: 57 (is equal to the atomic number for a neutral atom)
Neutrons = Mass number - Atomic number = 138 - 57 = 81
Electrons in neutral atom = Atomic number = 57
Third line:
Atomic number: 26 (from the Periodic Table, for the element Fe)
Protons: 26 (is equal to the atomic number for a neutral atom)
Neutrons = Mass number - Atomic number = 59 - 26 = 33
Nuclear symbol: ⁵⁹₂₆ Fe because the atomic number is 26 and mass number is 26.
the first three process involved in water purification can be summarize as
Answer:
Aeration,flocculation,coagulation.
Explanation:
Answer:
.
Explanation:
PLEASE HELP IF YOU KNOW I WILL MARK BRAINLIEST!!! A LOT OF POINTS!!
What is the solubility in Molarity of Ag2SO4 in a 0.1M solution of Sodium Sulfate at 25C?
Answer:
0.0039 mol/L
The molar solubility is 0.0039 mol/L, thus the common ion effect has reduced the solubility from 0.016 mol/L for Ag2SO4 in pure water to 0.0039 mol/L in the Na2SO4 solution.
Explanation:
