Answer:
Light
Explanation:
1 They were not albe to see at night because it was dark so the lack of light caused them to use echolocation.
Hope this helps
37. Using the reaction of nitrogen gas and hydrogen gas to make ammonia gas
(NH3), if you have 7 L of nitrogen, and all the hydrogen you need, how many
liters of ammonia gas can you make?
You can make 14 L of Ammonia
Further explanationAvogadro's hypothesis:
In the same T,P and V, the gas contains the same number of molecules
So the ratio of gas volume will be equal to the ratio of gas moles
[tex]\tt \dfrac{V_1}{n_1}=\dfrac{V_2}{n_2}[/tex]
Reaction
N₂+3H₂⇒2NH₃
Volume of Nitrogen-N₂ : V₁=7 L
From the equation above, mol ratio of N₂ : NH₃ =1 : 2, so volume of NH₃ :
[tex]\tt \dfrac{7}{1}=\dfrac{V_2}{2}\\\\V_2=\boxed{\bold{14~L}}[/tex]
What was a result of the Zhou capital being destroyed by invaders?
A) Leaders of the feudal states declared independence.
B) Loyal relatives supported the king to protect the empire.
C) Feudal rulers began to use nomadic soldiers in their armies.
D) Philosophers gained power by encouraging citizens to rebel.
Answer:
A
Explanation:
Answer:
think it is D
Explanation:
hope this helps
18.2 mL of a 0.156 M solution of lead(II) nitrate are added to 26.2 mL of a 0.274 M solution of potassium iodide.
What is the mass of the Pbl2 precipitate formed in the reaction Pb(NO3)2 (aq) + 2 KI (aq) - Pbl2 (s) + 2 KNO3? The molar mass of Pbly is 461.0 g/mol.
Provide your answer in units of grams, with the correct number of significant digits. Enter your answer as a number only; do not include units.
The mass of the Pbl2 : 1308.87
Further explanationGiven
18.2 mL of a 0.156 M Pb(NO3)2
26.2 mL of a 0.274 M KI
Reaction
Pb(NO3)2 (aq) + 2 KI (aq) - Pbl2 (s) + 2 KNO3
Required
the mass of the Pbl2
Solution
mol Pb(NO3)2 = 18.2 x 0.156 = 2.8392 mlmol
mol KI = 26.2 x 0.274 =7.1788 mol
Limiting reactant Pb(NO3)2(smaller ratio of mol : reaction coeffiecient)
mol Pbl2 based on limiting reactant (Pb(NO3)2)
From equation, mol ratio of Pb(NO3)2 : Pbl2 = 1 : 1, so mol Pbl2=mol Pb(NO3)2=2.8392
Mass Pb(NO3)2 :
[tex]\tt mass=mol\times MW\\\\mass=2.8392\times 461\\\\mass=1308.87~grams[/tex]
Suppose a student made a different sodium hydroxide solution using 0.401g of solid sodium hydroxide and 200mL of water. The student then standardized this solution using benzoic acid in a similar manner to that depicted in the simulation. From the following additional data recorded by the student: a) Mass of benzoic acid: 0.158g b) Volumer of the benzoic acid solution: 100.0mL c) Volume of sodium hydroxide need to neutralize the solution: 27.84mL Determine the molarity of the sodium hydroxide solution.
Answer:
0.05 M
Explanation:
Mass of benzoic acid= 0.158g
Volume of benzoic acid= 100 mL
Volume of sodium hydroxide = 27.84mL
Molar mass of benzoic acid= 122g/mol
Number of moles of benzoic acid= 0.158g/122g/mol= 1.3 × 10^-3 moles
C= no of moles/volume
C= 1.3 × 10^-3 moles × 1000/100
C= 0.013M
So;
Volume of acid VA = 100mL
Concentration of acid CA= 0.013M
Volume of Base VB = 27.84mL
Concentration of Base CB= ???
Number of moles of acid NA =1
Number of moles of Base NB= 1
From;
CAVA/CBVB= NA/NB
CAVANB= CBVBNA
CB= CAVANB/VBNA
CB= 0.013 × 100 × 1/27.84 × 1
CB= 0.05 M
Which elements are diatomic?
1
H
3
Li
6
с
7
N
8
0
9
F
5
B
13
AI
2
He
10
Ne
18
Ar
15
P
16
S
17
CI
11
Na
19
K
4.
Be
12
Mg
20
Ca
38
Sr
31
Ga
33
As
35
Br
36
Kr
34
Se
52
Te
14
Si
32
Ge
50
Sn
82
Pb
114
FI
51
Sb
53
1
37
Rb
55
Cs
54
Xe
E
86
49
In
81
TI
113
Nh
56
Ba
83
Ві
84
Po
85
At
Rn
87
Fr
88
Ra
115
Mc
116
Lv
118
117
Ts
Og
Diatomic elements have to atoms of the element in a molecule.
What are diatomic elements?Diatomic elements are those elements whose atoms combine together to form molecules of the element. The elements that are diatomic in the list are;
HNOFClBrSeTeHence, diatomic elements have to atoms of the element in a molecule.
Learn more about diatomic molecules: https://brainly.com/question/4979095
The pH scale for acids and bases ranges from
A. 17
B. 0-14
C. 1-14
D. 1-12
Answer: 0-14
Explanation: Hope this helps
How does heat differ from temperature?
O Temperature is the measure of heat.
O Temperature and heat are the same thing.
O Temperature measures thermal energy, and heat is the flow of thermal eneroy
O Temperature measures the loss of energy, and heat measures the gain of eneray.
Answer: Temperature measures thermal energy, and heat is the flow of thermal energy
Explanation:
Heat describes the transfer of thermal energy between molecules within a system. Heat measures how energy moves or flows. It is measured in Joules.
Temperature measures the hotmess or coldness of a body or how much thermal energy it contains . Temperature describes the average kinetic energy of molecules within a material or system. It is measured in Celsius (°C), Kelvin(K), or Fahrenheit (°F).
Thus the correct option is Temperature measures thermal energy, and heat is the flow of thermal energy
Answer:
its c
Explanation:
edg 2021
3. Which of the following statements is correct?
X Х
1 doubling the pressure of a gas doubles its volume
2. 2.00 L of air at 227°C has twice the pressure of the same 2.00 L of air at -
23°C
3. 2.00 L of air at 100°C has twice the pressure of the same 2.00 L of air at
50°C
4. halving the pressure of a gas halves its volume
Answer:
3. 2.00 L of air at 100°C has twice the pressure of the same 2.00 L of air at 50°C
Explanation:
1) doubling the pressure of a gas doubles its volume
This is incorrect because by increasing the pressure volume is going to be decreased.
2) 2.00 L of air at 227°C has twice the pressure of the same 2.00 L of air at 23°C
This is also incorrect because 2 L air at 227 °C will have the pressure more than twice time as compared to the 2L air at 23°C.
3. 2.00 L of air at 100°C has twice the pressure of the same 2.00 L of air at 50°C
This is correct;
According to Gay-Lussac Law,
The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.
Mathematical relationship:
P₁/T₁ = P₂/T₂
thus, by increasing the temperature pressure is also goes to increase in the same ratio.
4. halving the pressure of a gas halves its volume
This is incorrect because halving the pressure of gas increasing its volume.
Oxidation of a secondary alcohol results in the formation of a(n):________. a) tertiary alcohol b) acid c) aldehyde d) ketone
Answer:
A. Tertiary alcohol
Explanation:
Secondary alcohols are oxidized to ketones - and that's it. For example, if you heat the secondary alcohol propan-2-ol with sodium or potassium dichromate(VI) solution acidified with dilute Sulphuric acid, you get propanone formed. Playing around with the reaction conditions makes no difference whatsoever to the product.
When hydrogen reacts with calcium metal, what are the oxidation numbers of the calcium and hydrogen in the CaH2 product?
Ca(s)+ H2(g) → CaH2
a. +2 and -1
b. +1 and -2
c. +2 and 2
d. 0 and 0
e. -2 and +1
Answer: e. -2 and +1
Explanation:
Oxidation number or oxidation state : It represent the number of electrons lost or gained by the atoms of an element in a compound.
Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation number of the substance increases.
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation number of the substance gets reduced.
[tex]Ca(s)+H_2(g)\rightarrow CaH_2[/tex]
The oxidation number of calcium (Ca) in free state is 0 and in [tex]CaH_2[/tex] , it is -2.
The oxidation number of hydrogen in [tex]H_2[/tex] is zero and oxidation number of hydrogen in [tex]CaH_2[/tex] is +1 as in hydrides hydrogen loses electrons.
The oxidation number of calcium has been +2, and the oxidation number of hydrogen has been -1. Thus, the correct option is A.
The oxidation number can be defined as the number of electrons that have been lost by an atom in a chemical reaction.
The oxidation number can be calculated as the:
The oxidation number of Hydrogen when it combines with the less electronegative element has been -1.
There have been 2 atoms of Hydrogen that lose an electron, thus the total oxidation contribution of hydrogen has been -2.
The oxidation number of hydrogen has been -1.
The oxidation number of Calcium has been:
Ca atom has taken an electron from the hydrogen.
[tex]\rm Ca\;+\;e^-\;\rightarrow\;Ca^-[/tex]
The calcium takes one electron from each atom bonded. Thus the oxidation number of calcium has been +2.
The oxidation number of calcium has been +2, and the oxidation number of hydrogen has been -1. Thus, the correct option is A.
For more information about oxidation numbers, refer to the link:
https://brainly.com/question/15167411
Help me please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
Wave 2
Explanation:
Higher frequency means more energy per second, And wave 2 has higher frequesncy
please mark brainliest I’m almost at expert level
Answer:
I believe it is wave 2
Explanation:
As you can see in the graph, wave two happens to be more frequent. There are well, more waves than the first graph. Please forgive me if I am wrong. I tried my best to explain
24. H.SO, has
a) Ionic bond
b) both lonic and covalent bonds
c) ionic covalent and coordinate bonds
d) covalent bond
Answer:
b
Explanation:
Both ionic and covalent bonds when it has dissolved into water it will become ionic compound but when it was in gas situation it was covalent compound.
For the following reaction,use the identity of the alkyl halide and nucleophile to determine which substitution mechanism occurs.Then determine which solvent affords the faster reaction.
A) SN1,H2O
B) SN1,DMF
C) SN2,H2O
D) SN2,DMF
Answer:
a) SN1/H2O
b) SN1/CH3OH
c)SN2/DMF
d)SN2/HMPA
Explanation:
The reactions are shown in the image attached.
Let me restate the basic facts about SN1 and SN2 reaction mechanisms. SN1 reaction occurs by unimolecular mechanism and involves a carbocation, a poor nucleophile and a polar protic solvent.
An SN2 reaction is a bimolecular synchronous reaction that passes through a single transition state. It requires a good nucleophile and a polar aprotic solvent.
For reaction a and b, we observe that the alkyl halide is tertiary hence the reaction occurs by SN1 mechanism in the presence of a polar protic solvent.
Reactions c and d involves primary and secondary alkyl halides respectively and good nucleophiles. The best solvents to be used are polar aprotic solvents and the reaction follows SN2 mechanism.
if you start with 362 grams of C3 H8 how many grams of H2O will be produced
Answer:
52 g H2O (to 2 significant figures)
Explanation:
I hope you like my answer:)
Can you mark me as brainliest please
_______ are white blood cells that recognize specific antigens, and ultimately destroy them.
O lymphocytes
O pathogens
O water
Answer:
Lymphocytes
Explanation:
Pathogens are particles that make you sick like bacteria, viruses, amoebas. Water is essential for life but that's for metabolism, not fighting off against infection or viruses.
Answer:
Lymphocytes
Explanation:
lymphocytes are a kind of white blood cell (WBC). Lymphocytes are cells of the immune system and help fight infection. Lymphocytes live in lymph nodes, but also in the bloodstream and all over the body. Lymphocytes come in two main types: B-cells and T-cells
Where as water is totally not white blood cells and pathogens are viruses and bacterium
The graph models the amount remaining, in milligrams, of a radioactive substance as a function of time, in years. Explain the meaning of the point (3100) shown on the graph. Answer in complete sentences.
Answer:
Where is the grahppppp?!!!!
Name the following compound: S₂O₇
Answer:
disulfur heptoxide
Explanation:
What is weathering?
A.
the process by which sediment is compacted into rock
B.
the process by which rocks are broken down into sediment
C.
the process by which sediment is transported from one place to another
D.
the process by which sediment is deposited and built up into landforms
Answer:
B.
the process by which rocks are broken down into sediment
Silver nitride is formed when a silver cation that has a 1+ charge combines with a nitrogen anion that has a 3- charge. Write the formula for the compound silver nitride.
What happened to the celery if you put in food color water
Answer:
the celery would change colour!
Explanation:
How many moles are present in a 5.8 g sample of copper?
A. 11
B. 0.091
C. 0.91
D. 5.5 x 10^22
please i need this for my finals
Explanation:
Molar mass of Cu = 63.5g/mol
Moles of Cu
= 5.8g / (63.5g/mol) = 0.091mol (B)
The number of moles present in a 5.8 g sample of copper is equal to 0.0913 mol. Therefore, option B is correct.
What is a mole?A mole can be defined as an international scientific unit that is used to determine for given count of particles. The particles are commonly identical entities but they are individually distinct.
A mole of the substance can be used to evaluate a large number of atoms, molecules, or particular particles. The amount of material can be measured as chemical entities of a substance in a sample.
The number of units in 1 mole of a material is equal to 6.023×10²³ which is called Avogadro’s constant.
Given, the mass of the copper = 5.8 g
The mass of one mole of copper = 63.5 g
We can calculate moles as, n = Mass/molar mass
Then, the number of moles of copper = 5.8/63.5 = 0.0913 mol
Therefore, the number of moles of copper is 0.0913 mol.
Learn more about the mole, here:
brainly.com/question/26416088
#SPJ2
Explain what is meant by a half-life of 150 years. Then, write a function that models the amount, A, of a 100-mg sample remaining after T years for a substance with a half-life of 150 years. Use graphing software to graph the equation. Answer in complete sentences.
Answer:
Half-life of 150 years are those year that a radioactive element take to disintegrate to a half of it's original value.
I don't have graphical software
what are evidence that a chemical change has occurred
Answer:
Gas Bubbles Appear. Gas bubbles appear after a chemical reaction has occurred and the mixture becomes saturated with gas.
Formation of a Precipitate.
Color Change.
Temperature Change.
Production of Light.
Volume Change.
Change in Smell or Taste.
What os the formula for hexaboron tetrabromide
Answer:
B6Br4
Explanation:
Chemical formula gives a representation of the number of atoms that each element in a compound or molecule. In this question which is asking to give the formula of hexaboron tetrabromide, the hexa means 6 while the tetra means four.
Since the number of atoms of each element is written as a prefix before the main element, this means that the chemical formula of hexaboron tetrabromide will be B6Br4.
Which of the following factors affect the rate of weathering in an area?
A.
climate
B.
topography
C.
rock composition
D.
all of the above
Answer:
D
Explanation:
pretty sure D
When a mixture of rock pieces, salt and water is filtered, what will be found as the filtrate and what will be found as the residue
Answer:
Filtrate: Mixture of salt and water.
Residue: rock pieces
Answer:
Salt solution will be the filtrate
and the rock pieces will be the residue.
Explanation:
This is because salt is soluble in water and hence
it cannot be filtered out of water giving as a salt solution as the filtrate and since the rock pieces are not soluble in water they are left out and they become the residue.
what is 1.602176*10-¹⁹/ 1.758820*10¹¹C kg-¹
with proper explanation.
or expanded form
Answer:
0.00000000910938;
9.109380 * 10^-9
Explanation:
Given the question :
Given :
1.602176*10-¹⁹/ 1.758820*10¹¹
The numbers are expressed in the form:
A * 10^b ; Where;
A = Coefficient ; 10 = base ; b = exponent
The Coefficients can be divided directly as :
1.602176 / 1.758820 = 0.9109380
Using the division law of indices, the exponents acn be worked out as follows since they have the same base :
10^-19 / 10^-11 = 10^(-19 - (-11)) = 10^(-19+11) = 10^-8
Thus, we have ;
0.9109380 × 10^-8
In standard form:
9.109380 * 10^-9
In Expanded form:
10^-8 = 0.00000001
0.9109380 * 0.00000001 = 0.00000000910938
0.000000009 +
0.0000000001 +
0.00000000000 +
0.000000000009 +
0.0000000000003 +
0.00000000000008
__________________
0.00000000910938
___________________
What is the percentage of the actual yield of the reaction of 2.5 mol of Fe(NO3),
with 3.6 mol of Na2Co3, to form 6.3 mol of NaNO3 according to the reaction :
2Fe(NO3)3 + 3NaC03 - >
Fe2(CO3)3 + 6NaNO3 ?
Answer:
Percent yield = 87.5%
Explanation:
Given data:
Number of moles of Fe(NO₃)₃ = 2.5 mol
Number of moles of Na₂CO₃ = 3.6 mol
Actual yield of NaNO₃ = 6.3 mol
Percent yield of NaNO₃ = ?
Solution:
Chemical equation:
2Fe(NO₃)₃ + 3Na₂CO₃ → Fe₂(CO₃)₃ + 6NaNO₃
now we will compare the moles of both reactant with NaNO₃.
Fe(NO₃)₃ : NaNO₃
2 : 6
2.5 : 6/2×2.5 = 7.5
Na₂CO₃ : NaNO₃
3 : 6
3.6 : 6/3×3.6 = 7.2
Theoretical yield of NaNO₃ is 7.2 mol.
Percent yield:
Percent yield = actual yield / theoretical yield ×100
Percent yield = 6.3 mol / 7.2mol ×100
Percent yield = 87.5%
121
P(1)(1 + i)
1 + 11) 121 - 1
M = (1 + )
Answer:
121
Explanation:
add 1+120 to get answer
What else is produced during the combustion of propane, C3H8?
H2O ,
C3H8,
O2,
or
C3H8O2?
Answer:
H20
Explanation:
Answer:
The answer is H20
Explanation: