Why would a scientist need to know if there was a volcanic eruption about to happen?
Suppose that an individual's arm is cut, and because of this injury, bacteria are able to gain entry to the body and cause disease. What type of defense has been breached (overcome)?
adaptive defense
physical defense
chemical defense
Answer:
Physical :)
Explanation:
Skin works as a shield to the outside elements and does a good job of keeping the bad stuff out. :)
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If 25.0 g of NO are produced how many liters,at STP,of nitrogen gas are used?
Answer:
9 1/3 liters
Explanation:
N2 + O2 = 2 NO
Find mole weights from table of elements
N =14
O =~16 30 gm is a mole
22.4 l / mole for gases at STP
22.4 * 25/30 = 18 2/3 Liters of NO
but since Nitrogen is N2 it will take 1/2 s much = 9 1/3
*** EDITED ***
According to the stoichiometry and STP conditions if 25.0 g of NO are produced 2269 liters of nitrogen gas are used.
What is stoichiometry?It is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.
Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.1 mole of nitrogen gives 2 moles of NO, thus as per ideal gas equation which on substitution gives V=1×8.314×273/1=2269.722 liters.
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Name the cycloalkane.
CH3
CH3
CH3
trimethyl nonane
Explanation:
How many moles in 16 grams of oxygen?
Answer:
Half mole or 0.5 moles
__________________________________________________________
SolveOxygen has a molar molar mass of 32 g.
This means that O2 will have half that amount of grams, half-mole-substance.
6.022*10^23 molecules are present in one mole of any substance, so half it for O2.
6.022 × 10²³ [tex]-- >[/tex] 3.011 × 10²³
And simplified, that would make your answer 0.5 moles.
________________________________________________________
Questions?Ask in the comments box, please.
If 25.0 g NO are produced, how many grams of nitrogen gas are used?
A: 5.84 g
B: 11.7 g
C: 23.3 g
D: 33.6 g
Based on the assumption that the reaction involves N and O to produce NO, if 25.0 g of NO are produced, the amount of N gas used would be 11.66 grams
Stoichiometric calculationFrom the equation of the reaction:
N + O ---------> NO
Mole ratio of N to NO is 1:1
Mole of 25.0 g of NO = 25/30.01 = 0.833 moles
Equivalent mole of N = 0.833 moles
Mass of 0.833 moles N = 0.833 x 14 = 11.66 grams
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What amount of heat is required to increase the temperature of 75.0 g of water from 22.3˚C to 36.1˚C?
Answer:
4332.5 j
Explanation:
Specific heat of water is 4.186 j /g-C
4.186 j / g-C * 75 g * (36.1-22.3 C) =
The solubility of a gas is 0.890 g/L at a pressure of 120 kPa. What is the solubility of the gas if the pressure is changed to 100 kPa, given that the temperature is held constant?
For the solubility of a gas is 0.890 g/L at a pressure of 120 kPa, the solubility of the gas, if the pressure is changed to 100 kPa is mathematically given as
c=0.741g/l
What is the solubility of the gas if the pressure is changed to 100 kPa, given that the temperature is held constant?Generally, the equation for the Pressure is mathematically given as
p=kc
Therefore
k=p/c
k = 120 /0.890
k=134.8
In conclusion, if p=100kpa
c=p/k
c=100/134.8
c=0.741g/l
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Answer:
a reaction that can occur in both forward and reverse directions at the same time.
Explanation:
This is because ↓
A reversible reaction is a reaction in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously. A and B can react to form C and D or, in the reverse reaction, C and D can react to form A and B.
Hope this helps =)
Potassium chlorate decomposes to form potassium chloride and oxygen according to the following
equation:
2 KCIO3(s) + 2 KCl(s) + 3 O2(g)
How many grams of oxygen are produced if 244 grams of potassium chlorate decompose and 148
grams of potassium chloride are produced?
O 1.65 g
O 0.607 g
0 96.0 g
O 392 g
Answer:
O 392 g
Explanation:
39.2 grams of oxygen (O2) can be produced.
The concept stoichiometry is used here to determine the grams of oxygen produced. The amount of oxygen produced from the decomposition of 244 grams of potassium chlorate is 96.0 g . The correct option is C.
What is stoichiometry?The stoichiometry is an important concept in chemistry which helps us to use the balanced chemical equation to calculate the amount of reactants and products. Here we make use of the ratios from the balanced equation. It help us to understand how much substance is needed or present.
Here the balanced reaction is:
2 KCIO₃(s) + 2 KCl(s) + 3 O₂(g)
2 moles of KCIO₃ = 2(39 + 35.5 + 3 × 16) = 245 g
3 moles of O₂ = 3 × 2 × 16 = 96 g
245 g KCIO₃ produces 96 g O₂
Therefore 245 g gives 96 × 244/245 = 95.6 g ≈ 96.0 g
Thus the correct option is C.
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what are the units on avogardo’s number
Answer:
I believe they are electrons, atoms, ions, or molecules.
Explanation:
Is apologize if it is incorrect-
I hope it helps! Have a great day!
Muffin~
Answer:
Units:
electrons
ions
atoms
molecules
Explanation:
I hope it helps!
Have a great day!
<3
What is the 2nd step in the process of natural selection?
Answer: Selection proper
Explanation:
it's an anti-chance process, but subject to many constraints
How many atoms in total are present in sucrose C12H2011 weighs 1.4 mg
Answer:
2.46×10²¹atoms
Explanation:
[tex]molar \: mass \: of \: the \: sucrose = 12(12) + 22(1) + 11(16) \\ = 144 + 22 + 176 \\ = 342g {mol}^{ - 1} \\ mole = \frac{1.4 \times {10}^{ - 3} }{342} \\ = 4.09 \times {10}^{ - 6} \\ number \: of \: atoms = 4.09 \times {10}^{ - 6} \times 6.022 \times {10}^{23} \\ = 2.46 \times {10}^{21} atoms[/tex]
how many molecules of oxygen are contain in 100 ml of air at NTP? (air contains 21% oxygen by volume
Answer:
600
Explanation:
because if there's 6 molecules in each then 6×100 is 600
Can anyone help me please
Answer:
Nucleic acids
Explanation:
all organic foods (fruit, meat, etc) contain it to some degree. because all organic foods have dna in them.
Which conditions will increase the rate of a chemical reaction?.
Answer:
temperatures
enzyme activity
If 162.35 g aluminum hydroxide are dissolved in 6750 mL of solution, what is the concentration of the solution?
If 162.35 g aluminum hydroxide are dissolved in 6750 mL of solution, the concentration of the solution is 0.308M
How to calculate concentration?The concentration of a solution can be calculated using the following formula:
Molarity = no of moles ÷ volume (L)
However, the number of moles in 162.35g of Al(OH)3 must be calculated as follows:
Molar mass of Al(OH)3 = 78g/mol
no of moles = 162.35g ÷ 78mol
no of moles = 2.08mol
Molarity = 2.08mol ÷ 6.75L
Molarity = 0.308M
Therefore, if 162.35 g aluminum hydroxide are dissolved in 6750 mL of solution, the concentration of the solution is 0.308M.
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What is the oxidation number of chromium in sodium dichromate, na2cr2o7?.
Answer:+6
Explanation:Oxygen always has an ON of -2 so when there’s O7 the total is -12. Sodium is in group 1 so has an ON of +1 that means with two of them it’s overall ON is +2. When you combine the two that equals -12 but you want it to equal 0. So it would be +12. Considering there are two chromium present you would divide that by 2 making the answer +6.
Question 4 of 10
Match the feature with its description.
Sinkholes
?
Hang from cave ceilings.
Stalagmites
?
Grow from cave floors.
Stalactites
?
Collapsed caves.
Speleothems
?
Cave features.
Speleothems
Answer:
Stalactites - Hang from caves ceilings
Stalagmites - Grow from cave floors
Sinkholes - Collapsed caves
Speleothems - Cave features
Explanation:
Got it right :)
In a typical mammalian cell, the net transport by the sodium-potassium exchange pump that maintains the 70 mv membrane potential is 500 singly charged ions per second.
For a typical mammalian cell, the net transport by the sodium-potassium exchange pump, Work done is mathematically given as
W= 5.6*10-18 J
How much work does the pump do each second?Generally, the equation for the Potential difference is mathematically given as
Potential difference = Work done / Charge
Therefore
W=q*P.d
Q= 500 * 1.6*10-19 C
P.d. = 70 mV
In conclusion,Workdone
W500 * 1.6*10-19 * 70*10-3
W= 5.6*10-18 J
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3.0 Liters of gas at a pressure of 0.90 atm is compressed to 2.0 atm.
What is the new volume?
Answer:
5.5 L
Explanation:
Of the following substances, which one will heat up the FASTEST?
Ammonia (4.70 J/g°C)
Aluminum (0.90 J/gºC)
Gold (0.13 J/gºC)
Ethylene glycol (2.42 J/g°C)
A. Ethylene glycol
B. Aluminum
C. Ammonia
D. Gold
Identify whether each compound is a straight chain, branched chain, or cycloalkane.
Answer:
the first one is branched, the second one is also branched and the third one is cycloalkane
Answer:
A: straight chain, B: branched chain, and C: cycloalkane.
Explanation:
How many energetically equivalent ways can you distribute the particles in system a?.
The number of energetically equivalent ways that one can distribute the particles in system A and B are 1 and 6 respectively.
How to calculate the number of ways?From thx complete information, system A has only 1 distribution that's possible.
For system B, the number of ways will be:
= 3 × 2 × 1
= 6
In conclusion, the correct options are 1 and 6 respectively.
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Draw the lewis structure of sf2, showing all lone pairs.
Answer:
Number of valence electrons in two F atom = 2(7) = 14
Total number of valence electrons = 6 + 14 = 20 electrons
Placing a bonding pair of electrons between the atoms to form the chemical bonds.
Electrons used in bonding = 4
The remaining electrons are used as a lone pair for central or terminal atoms to achieve an octet to finish the Lewis dot structure.
Electrons used as a lone pair = 20 - 4 = 16
Explanation:
hope this helps
A sample of an ideal gas at 1.00 atm and a volume of 1.96 L was placed in a weighted balloon and dropped into the ocean. As the sample descended, the water pressure compressed the balloon and reduced its volume. When the pressure had increased to 15.0 atm, what was the volume of the sample
Answer: 0.130 L
Explanation:
Explain what the color change indicated about the changes in the concentrations of Co(H2O)62+ and CoCl42– in each trial.
Trail one
starting color: purple
added 3 drops of Hcl(aq)
end color:blue
Trail two
start color is :blue
added 3 drops of AgNOv3(aq)
and White stuff forms at the bottom.
end color is: light pink
Addition of HCl leads to te formation of blue CoCl4^2– while the addition of AgNO3 leads to the formation of pink Co(H2O)6^2+.
What is equilibrium?Dynamic equilibrium is said to have been attained in a reaction when the rate of forward reaction is equal to the rate of reverse reaction. Now we have the equilibrium as shown in the image attached.
When we add HCl as in trial 1, the equilibrium position is shifted to the left and blue CoCl4^2– is formed. When we add AgNO3, the Cl^- is precipitated out of solution and the equilibrium shifts towards the left to yield pink Co(H2O)6^2+.
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Which compound below will readily react with a solution of bromine consisting of 48% hydrobromic acid and 30% hydrogen peroxide?
Answer:
cyclohexene I think that's the answer
which word help the reader understand the meaning of stratum in paragraoh 3.
Answer:
It should be D
Explanation:
Stratum is a layer of rock in the ground
SECOND TERM 2021/2022 HOLIDAY ASSIGNMENT
SUBJECT: CHEMISTRY CLASS SS1
1 (a) Define a salt
(b) The basicity of tetraoxosulphate VI acid is 2. Explain this statement with equation showing
the reaction between the acid and potassium hydroxide
2. Define buffer solution and give two uses of buffer solutions.
3. Explain and give an example each of
(a) Hygroscopy (b) Efflorescence (c) Deliquescence
4. The concentration of hydrogen ion H⁺ in two solutions are:
(a) 1 x 10⁻³moldm⁻³ and (b) 6 x 10⁻⁹moldm⁻³
What is the pH of each solution?
5. (a) Give three crystalline and four non-crystalline allotropes of carbon
(b) Give three differences between the two main crystalline allotropes of carbon.
1.
a) Salt: any chemical compound formed from the reaction of an acid with a base, with all or part of the hydrogen of the acid replaced by a metal or other cation.
Acid + alkali → salt + water
b)
Tetraoxosulfate (VI), SO2−4,SO42−, is the second conjugate base from the dissociation of sulfuric acid, H2SO4.H2SO4. This acid is a diprotic acid and thus can donate two protons in an aqueous solution to form HSO−4HSO4− after the first dissociation and SO2−4SO42− after the second dissociation.
The fact that tetraoxosulfate (VI) is dibasic means in terms of Brønsted-Lowry acid-base theory, the ion can accept two protons, or in other words, the parent acid donates two protons upon dissociation. This can be shown by the equation of the reaction between the parent sulfuric acid and potassium hydroxide where two hydrogens are replaced:
H2SO4+2KOH → K2SO4+2H2O
2. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. In nature, there are many systems that use buffering for pH regulation.
For example, blood in the human body is a buffer solution.
Buffer Solutions are used for fermentation in the making of alcohol
I've only answered 1 & 2
