Answer:
I found this on the internet People need to breathe, and so do lots of other animals—and plants! Breathing is part of a process called respiration. During respiration, a living thing takes in oxygen from the air and gives out carbon dioxide.
Explanation:
10 Interesting Things About Air | NASA Climate Kidsclimatekids.nasa.gov › 10-things-air
Your welcome!
to breath
with out air we can't live here
620 mL of nitrogen at standard pressure is compressed into a 480 mL container. What is the new pressure in kPa?
a. 982 kPa
b. 1.29 kPa
c. 131 kPa
d. 78.4 kPa
Answer:
c. 131 kPa
Explanation:
Hello!
In this case, since the relationship between volume and pressure is inversely proportional, based on the Boyle's law:
[tex]P_1V_1=P_2V_2[/tex]
Considering that the standard pressure is 101.325 kPa, we can compute the final pressure as shown below:
[tex]P_2=\frac{P_1V_1}{V_2}=\frac{620mL*101.325kPa}{480mL}\\\\P_2=131kPa[/tex]
Therefore, the answer is c. 131 kPa .
Best regards!!
A chemist carefully measures the amount of heat needed to raise the temperature of a 0.47 kg sample of C6H7N from 30.5 degrees C to 48.4 degrees C. The experiment shows that 1.65 x 10^4 J of heat are needed. What can the chemist report for the molar heat capacity of C6H7N? Be sure your answer has the correct number of significant digits.
[tex]\bull\sf m=0.47kg[/tex]
[tex]\bull\sf \Delta T=T_f-T_i=48.4-30.5=17.9°C[/tex]
[tex]\bull\sf Q=1.65\times 10^4J[/tex]
We know according to thermodynamics
[tex]\\ \sf\longmapsto Q=mc\Delta T[/tex]
[tex]\\ \sf\longmapsto c=\dfrac{Q}{m\Delta T}[/tex]
[tex]\\ \sf\longmapsto c=\dfrac{1.65\times 10^4}{0.47\times 17.9}[/tex]
[tex]\\ \sf\longmapsto c=\dfrac{1.65\times 10^4}{8.413}[/tex]
[tex]\\ \sf\longmapsto c=0.1961\times 10^4J/kg°C[/tex]
[tex]\\ \sf\longmapsto c=1961J/kg°C[/tex]
of the element listed wich
has the largest atomic rodius?
Calcium Cas Copper (ca)
Chromium (Cr)
Cobalt (co)
The atomic radius trend on the Periodic Table is as follows:
- Atomic radius increases down a column (or group)
- Atomic radius decreases across rows (or periods) from left to right
Looking at my Periodic Table, calcium, chromium, cobalt and copper are in that order from left to right in the same period, which simplifies things significantly.
Since these elements are in the same period, and given that we know atomic radius decreases across periods from left to right, we can see that calcium has the largest atomic radius.
I need help with this. Read instructions and help plzz
Answer:
e
Explanation:
plz help me... my ppr is gonig on......
In first line of Lyman Series, wave number is
1 point
82.26 x 10^5
97.49 x 10^5
109.678 x 10^5
none
Answer:
geruow0irghvn3p0unhie0ghik
Explanation:
Find the pH of the equivalence point and the volume(ml) of 0.125M HCl needed to reach the point in titrations of: a) 65.5ml of 0.234M NH3.b) 21.8 mL of 1.11 M CH3NH2.
Answer:
a. 122.6 mL / pH = 4.03
b. 193.6 mL / pH = 5.73
Explanation:
In the equivalence point we know: mmoles acid = mmoles base- And the pH in a titration between a weak base and a strong base, is acid, at the equivalence point. For the volume, we can replace the equation with the data given.
a. 0.125M . volume of acid = 65.5 mL . 0.234M
Volume of acid = (65.5 . 0.234) / 0.125 = 122.6 mL
Total volume at the equivalence point = 188.1 mL
b. 0.125M . volume of acid = 21.8 mL . 1.11 M
Volume of acid = (21.8 . 1.11) / 0.125 = 193.6 mL
Let's calculate the pH. In the equilavence point we have a neutralization reaction.
a. NH₃ + HCl → NH₄Cl
All the mmoles of protons (65.5 mL . 0.234M) react to ammonia, to obtain ammonium.
New concentration is: 15.32 mmoles / 188.1 mL = 0.0814 M
This is the [NH₄⁺] to determine the pH in the acid base equilibrium.
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺ Ka
Expression for Ka = [NH₃] . [H₃O⁺] / [NH₄⁺]
5.6×10⁻¹⁰ = x² / (15.32 - x)
(We can avoid the quadratic equation 'cause Ka is so small)
√(5.6×10⁻¹⁰ . 15.32) = x → [H₃O⁺] = 9.26×10⁻⁵
pH = - log [H₃O⁺] → 4.03
b. CH₃NH₂ + HCl → CH₃NH₃Cl
All the mmoles of protons (21.8 mL . 1.11M) react to methylamine, to obtain methylammonium.
New concentration is: 24.2 mmoles / 193.6 mL = 0.125 M
This is the [CH₃NH₃⁺] to determine the pH in the acid base equilibrium.
CH₃NH₃⁺ + H₂O ⇄ CH₃NH₂ + H₃O⁺ Ka
Expression for Ka = [CH₃NH₂] . [H₃O⁺] / [CH₃NH₃⁺]
2.7×10⁻¹¹ = x² / (0.125 - x)
(We can avoid the quadratic equation 'cause Ka is so small)
√(2.7×10⁻¹¹ . 0.125) = x → [H₃O⁺] = 1.84×10⁻⁶
pH = - log [H₃O⁺] → 5.73
The pH of the equivalence point of 0.125M HCl with NH₃ is 4.03 and with CH₃NH₂ is 5.73.
What is equivalence point?In the acid - base titration, at the equivalence point equal moles of acid as well as of base are present.
First we calculate the volume of HCl by using the below equation as:
M₁V₁ = M₂V₂, whereM₁ = molarity of NH₃ = 0.234 M
V₁ = volume of NH₃ = 65.5 mL
M₂ = molarity of HCl = 0.125 M
V₂ = volume of HCl = ?
V₂ = (65.5 . 0.234) / 0.125 = 122.6 mL
Total volume at the equivalence point = 188.1 mL
Chemical reacion will be written as:
NH₃ + HCl → NH₄Cl
All moles of protons react with moles of ammonia, so new moles (n) will be calculated as:
n = molarity × volume
n = 65.5 mL × 0.234M = 15.32 moles
Now, concentration in terms of molarity will be 15.32 mmoles / 188.1 mL = 0.0814 M
pH in the acid-base reaction due to [NH₄⁺], as:
NH₄⁺ + H₂O ⇄ NH₃ + H₃O⁺
Value of Ka for this reaction is = 5.6×10⁻¹⁰
According to the ICE table, Ka equation will be written as-
5.6×10⁻¹⁰ = x² / (15.32 - x)
x = [H₃O⁺] = 9.26 × 10⁻⁵
pH = - log [H₃O⁺] = 4.03
Again we calculate the volume of HCl with the CH₃NH₂ as:0.125M . volume of acid = 21.8 mL . 1.11 M
Volume of acid = (21.8 . 1.11) / 0.125 = 193.6 mL
Total volume at the equivalence point = 215.4 mL
Chemical reacion will be written as:
CH₃NH₂ + HCl → CH₃NH₃Cl
All moles of protons react with moles of ammonia, so new moles (n) will be calculated as:
n = 21.8 mL . 1.11M = 24.2 moles
Now, concentration in terms of molarity will be 24.2 moles / 215.4 mL = 0.11M
pH in the acid-base reaction due to [CH₃NH₃⁺], as:
CH₃NH₃⁺ + H₂O ⇄ CH₃NH₂ + H₃O⁺
Value of Ka = 2.7×10⁻¹¹
According to the ICE table, Ka equation will be written as-
2.7×10⁻¹¹ = x² / (0.11 - x)
x = [H₃O⁺] = 5.4×10⁻⁶
pH = - log [H₃O⁺] = 5.73
Hence the value of pH will be 4.03 and 5.73 respectively.
To know more about equivalence point, visit the below link:
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How many seconds are in 100 years
What are five minerals found on space rocks
Answer:
oxygen, silicon, iron, calcium, sodium
Explanation:
these are all found in space rocks known as meteorites. hope this helps :)
What is used to measure heat?
O change in temperature
O constant temperature
O constant specific heat
O change in specific heat
Answer:
O constant specific heat
Explanation:
Write a balanced half-reaction for the oxidation of gaseous nitric oxide (NO) to aqueous nitrous acid (HNO2) in acidic aqueous solution.
Answer:
NO + H₂O → HNO₂ + 1 e- + 1 H⁺
Step-by-step explanation:
NO ⇒ oxidation number of N = +2
HNO₂ ⇒ oxidation number of N= +3
Therefore, NO has to lose 1 electron to be oxidized to HNO₂. We write the half-reaction with 1 electron (1 e-) in the products side.
NO → HNO₂ + 1 e-
Now, we have 0 electrical charges in the reactants side, and a total of -1 electrical charge in the products side. As the reaction is in acidic aqueous solution, we have to add H⁺ ions to balance the charges. We perform the balance by adding 1 H⁺ (positive charge) to neutralize the negative charge in the side of the products:
NO → HNO₂ + 1 e- + 1 H⁺
Now, we perform the mass balance. We have:
N: 1 atom in both sides
O: 1 atom in reactants side and 2 atoms in products side
H: 0 atoms in reactants side, 2 atoms in products side.
Thus, we have to add 1 H₂O molecule to the reactants side to equal the masses:
NO + H₂O → HNO₂ + 1 e- + 1 H⁺
Finally, the oxidation half-reaction is:
NO + H₂O → HNO₂ + 1 e- + 1 H⁺
at STP how many molecules of nitrogen gas are in 224 L?
a.6.022x10^22
b.6.022x10^23
c.6.022x10^24
d.6.022x10^25
Answer:
6.022×10²² molecules
Explanation:
Given data:
Volume of nitrogen = 224 L
Pressure = standard = 1 atm
Temperature = standard = 273 K
Number of molecules = ?
Solution:
PV = nRT
1 atm × 224 L = n × 0.0821 atm.L/mol.K × 273 K
224 atm.L = n ×22.41 atm.L/mol
n = 224 atm.L/22.41 atm.L/mol
n = 10 mol
1 mole contain 6.022×10²³ molecules
10 mol×6.022×10²³ molecules/ 1 mol
60.22×10²³ molecules
6.022×10²² molecules
Answer:
thank you! ladies... love the answer is A) 6.022 x 10 ^22
Explanation:
love this one!
have a good one everyone
Isotope Atomic Mass (amu) Percent Abundance
Silicon-28 27.98 92.21%
Silicon-29 28.98 4.70%
Silicon-30 29.97 3.09%
Look at the information given and predict whether the average atomic mass would be closer to Si-28, Si-29, or Si-30. Give reasons for your answer.
Answer:
The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.
Explanation:
Given data:
Atomic mass of silicon= ?
Percent abundance of Si-28 = 92.21%
Atomic mass of Si-28 = 27.98 amu
Percent abundance of Si-29 = 4.70%
Atomic mass of Si-29 = 28.98 amu
Percent abundance of Si-30 = 3.09%
Atomic mass of Si-30 = 29.97 amu
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)+(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (92.21×27.98)+(4.70×28.98)+(3.09×29.97) /100
Average atomic mass = 2580.04 +136.21+92.61 / 100
Average atomic mass = 2808.86 / 100
Average atomic mass = 28.08amu.
The average atomic mass is closer to Si- 28 because this isotope is present in more percentage in the sample.
Answer:
The average atomic mass of silicon would be closer to Si-28 as it is the most abundant isotope.
Explanation:
From PLATO
Which major product is formed when Br2 and H2O are added to 2-methylpropene to give the bromohydrin?
Answer:
See explanation and image attached
Explanation:
The addition of hypohalous acids to alkenes follows the Markovnikov rule. This rule states that the negative part of the addendum is joined to the carbon atom with the least number of hydrogen atoms (more substituted carbon atom).
In the addition of hypohalous acids, the halogen is the positive end of the addendum and the OH^- is the negative end of the addendum. This explains the product shown in the image attached.
A gas at -20c occupies volume 140 ml calculate temperature at which the volume of the gas becomes 65 ml pressure constant
Answer:
–156 °C
Explanation:
The following data were obtained from the question:
Initial temperature (T1) = –20 °C
Initial volume (V1) = 140 mL
Final volume (V2) = 65 mL
Final temperature (T2) =?
Pressure = constant.
Next, we shall convert –20 °C to Kelvin temperature. This can be obtained as follow:
T(K) = T(°C) + 273
Initial temperature (T1) = –20 °C
Initial temperature (T1) = –20 °C + 273 = 253 K.
Next, we shall determine the new temperature of the gas as follow:
Initial temperature (T1) = 253 K
Initial volume (V1) = 140 mL
Final volume (V2) = 65 mL
Final temperature (T2) =?
V1/T1 = V2/T2
140/253 = 65/T2
Cross multiply
140 × T2 = 253 × 65
140 × T2 = 16445
Divide both side by 140
T2 = 16445 /140
T2 = 117 K
Finally, we shall convert 117 K to celcius temperature. This can be obtained as follow:
T(°C) = T(K) – 273
T2 = 117 K
T2 = 117 K – 273
T2 = –156 °C
Thus, the new temperature of the gas is –156 °C
12oz of water initially at 75oF is mixed with 20oz of water intiially at 140oF. What is the final temperature?
Answer:
[tex]115.625^{\circ}\text{F}[/tex]
Explanation:
[tex]m_1[/tex] = First mass of water = 12 oz
[tex]m_2[/tex] = Second mass of water = 20 oz
[tex]\Delta T_1[/tex] = Temperature difference of the solution with respect to the first mass of water = [tex](T-75)^{\circ}\text{F}[/tex]
[tex]\Delta T_2[/tex] = Temperature difference of the solution with respect to the second mass of water = [tex](T-75)^{\circ}\text{F}[/tex]
c = Specific heat of water
As heat gain and loss in the system is equal we have
[tex]m_1c\Delta T_1=m_2c\Delta T_2\\\Rightarrow m_1\Delta T_1=m_2\Delta T_2\\\Rightarrow 12(T-75)=20(140-T)\\\Rightarrow 12T-900=2800-20T\\\Rightarrow 12T+20T=2800+900\\\Rightarrow 32T=3700\\\Rightarrow T=\dfrac{3700}{32}\\\Rightarrow T=115.625^{\circ}\text{F}[/tex]
The final temperature of the solution is [tex]115.625^{\circ}\text{F}[/tex].
Which of these mixtures would NOT be separated by using simple distillation?
Ink and water
Salt and water
Sand and water
There is a golden role of solubility, polar solute dissolve in polar solvent and non polar solute dissolve in non polar solvent. Therefore, the correct option is option B that is Salt and water.
What is solution?Solutions are a homogeneous mixture of two or more substances. A solution is a homogeneous mixture of solvent and solute molecules. Solvent is a substance that is in large amount in solution. solute is the substance which is in small amount in a solution. There are two types of mixture that is homogeneous and heterogeneous. Solution is a homogeneous solution.
Salt and water because salt is transparent and will dissolve into the water among given solute, salt NaCl is a polar solute which will dissolve in polar solvent that is water.
Therefore, the correct option is option B that is Salt and water.
To know more about solution, here:
https://brainly.com/question/13812915
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In a titration, you start with 0.05 M sodium hydroxide (NaOH) and slowly add it to 40 mL of HC1 with an unknown concentration. What is the original concentration of the HC1 if you add a total of 15.4 mL of sodium hydroxide to the HC1 to achieve pH =7?
Answer:
The original concentration of the HCl is: 0.01925 M
Explanation:
Equation:
HCl+NaOH-------> NaCl+H₂O
Volume of NaOH added = 0.05 M
No of moles of NaOH = 15.4 mL [tex]x\frac{1 L}{1000 mL} x\frac{0.05 mol NaOH}{L}[/tex]
= 0.00077 mol NaOH
Then,
Volume of HCl solution = 40 mL x 1/1000 mL
= 0.0400 L
Therefore,
Concentration of HCl = 0.00077 mol/0.0400 L
= 0.01925 M
Now, to find the pH:
pH = -log₁₀[H⁺]
= -log₁₀(2x10⁻⁶)
= 5.7
Calculate the pH of a solution that is 0.291 M acetic acid and 0.123 M sodium acetate. The Ka of acetic acid is 1.76×10^–5 at 25°C. What is the pH of this mixture at 0°C?
Answer:
The answer is "4.37."
Explanation:
at [tex]0^{\circ} C\ Ka = 1.76 \times 10^{-5}[/tex]
[tex]\to pKa = - \log \ Ka[/tex]
[tex]= - \log \ 1.76 \times 10^{-5}\\\\ = 4.75[/tex]
[tex]pH = pKa + \log \frac{[sodium \ acetate]}{[acetic \ acid]}[/tex]
[tex]= 4.75 + \log \frac{[0.123]}{[0.291]}\\\\= 4.75+ \lg(0.422680412)\\\\=4.75-0.373987878\\\\=4.37601212\\\\=4.37[/tex]
Metals have the ability to conduct electricity more effectively than other materials, such as ionic and covalent substances. This is because the way metals bond -
Answer:
See explanation
Explanation:
Substances are composed of bands. A band is a group of molecular orbitals, the energy differences between them are so small that the system behaves as if a continuous, non-quantization of energy within the barrier is possible.
Materials consists of a valence band and a conduction band separated by a band gap. A band gap occurs when the energy difference between two bands is significant.
The magnitude of band gap determines whether a material will be a metal, nonmetal or metalloid.
Metals have a very little band gap hence they are able to conduct electricity more effectively than other materials, such as ionic and covalent substances.
A cation is a _______ion
Positive b. Negative c. Neutral
Answer:
Positive
Explanation:
There are more protons than electrons making it positive
Use Coulomb's Law to explain why and how atomic radius and IE have an inverse relationship.
Answer:
Such a relationship between atomic number and atomic radius is a direct correlation. an inverse correlation. According to Coulomb's Law, as the atomic number increases within a series of atoms, the nuclear attraction for electrons will also increase, thus pulling the electron(s) closer to the nucleus.
Explanation:
I need help with this, please I need it ASAP
It's science, ignore that it says Chemistry. There was no science
A chemistry student needs 15.0 g of methyl acetate for an experiment. By consulting the CRC Handbook of Chemistry and Physics, the student discovers that the density of methyl acetate is 0.934 g/mL. Calculate the volume of methyl acetate the student should pour out. Be sure answer has the correct number of significant digits.
Answer:
16mL.
Explanation:
From the Question above we have the following parameters/information which is going to help in solving this particular Question;
=> The mass methyl acetate that the student needed is = 15.0g.
=> The density of methyl acetate given is = 0.934 g/mL. (Kindly remember that formula for Determining density of a particular substance = density = mass/volume.
Hence, the volume of methyl acetate needed to be poured away can be calculated from the formula for calculating density.
Density = mass/ volume.
Density = 0.934 g/mL., and mass = 15.0g. Therefore, the volume = mass/density.
Volume = 15.0g/ 0.934 g/mL = 16 mL.
How many centimeters are in .479 kilometers
Answer:
47900 cm
General Formulas and Concepts:
Chemistry
Base 10 Decimal SystemUsing Dimensional AnalysisExplanation:
Step 1: Define
0.479 km
Step 2: Identify Conversions
1 km = 1000 m
1 m = 100 cm
Step 3: Convert
[tex]0.479 \ km(\frac{1000 \ m}{1 \ km} )(\frac{100 \ cm}{1 \ m} )[/tex] = 47900. cm
Step 4: Check
We are given 3 sig figs. Follow sig fig rules.
47900. cm ≈ 47900 cm
A small stream runs through a neighborhood. For many years, the shape of the streambed, the amount of water, and the species of wildlife remained stable. However, there has been an increase in construction in the area. New homes, new streets, and new storm drains have affected the area. What effect have the changes likely had on the local stream?
HELP FAST
Answer:
the water has been poulutid due to all of the construction and debris that might have flown into the water.
Explanation:
If 125 g of CaCO3 is mixed and reacted with 125 g of HCl, which reactant is limiting and how many grams of CO2 can be made?
Answer:
CaCO3 is the limiting reactant
55 g of CO2 is made
Explanation:
First we must put down the reaction equation;
CaCO3(s) + 2HCl(aq) ---------> CaCl2(s) + H2O(l) + CO2(g)
Number of mole of CaCO3 = 125g/100gmol-1 = 1.25 moles
From the reaction equation;
1 mole of CaCO3 yields 1 mole of CO2
Hence 1.25 moles of CaCO3 yields 1.25 moles of CO2
For HCl;
number of moles of HCl = 125g/36.5 g mol-1 = 3.42 moles
From the reaction equation;
2 moles of HCl yields 1 mole of CO2
3.42 moles of HCl yields 3.42 * 1/2 = 1.71 moles of CO2
Hence CaCO3 is the limiting reactant.
Mass of CO2 produced = 1.25g * 44 gmol-1 = 55 g of CO2
Questions
1) Would it be possible to run a chemical reaction with no single limiting reagent? Why or why not?
Answer:
That's not possible. When a limiting reactant is called out in a stoichiometry problem, what that means is there's enough of all the other reactants for the limiting one to be completely consumed in the formation of product/products
A solution of cough syrup contains 5.00% active ingredient by volume. If the total volume of the bottle is 80.0 mL , how many milliliters of active ingredient are in the bottle?
Answer:
someone is in my mind and it is telling me 5.55m
Explanation:
Answer:
4 mL
Explanation:
4mL is 5% of 80mL. Therefore my answer is right.
What color flame did lead nitrate produce?
yellow-red
blue
green
purple
Answer: it blue
Explanation:
Combustion of hydrocarbons such as nonane (C9H20) produces carbon dioxide, a "greenhouse gas." Greenhouse gases in the Earth's atmosphere can trap the Sun's heat, raising the average temperature of the Earth. For this reason there has been a great deal of international discussion about whether to regulate the production of carbon dioxide. 1. Write a balanced chemical equation, including physical state symbols, for the combustion of liquid nonane into gaseous carbon dioxide and gaseous water.
2. Suppose 0.210kg of nonane are burned in air at a pressure of exactly 1atm and a temperature of 15.0°C. Calculate the volume of carbon dioxide gas that is produced. Round your answer to 3 significant digits.
Answer:
349 L (To 3 significant figures)
Explanation:
The reaction equation is;
C9H20(l) + 14O2(g) ------> 9CO2(g) + 10H2O(g)
number of moles of nonane in 0.210 Kg = mass/molar mass
molar mass of nonane = 9(12) + 20(1) = 128 gmol-1
Hence number of moles = 0.210 * 10^3g/128 gmol-1 = 1.64 moles
If 1 mole of nonane produced 9 moles of CO2 from the balanced reaction equation;
1.64 moles of nonane will produce 1.64 * 9/1 = 14.76 moles of CO2
Now from the ideal gas equation;
PV=nRT
P = 1 atm
V= the unknown
n= 14.76
R = 0.082 atmLmol-1K-1
T = 15 + 273 = 288 K
V= nRT/P
V = 14.76 * 0.082 * 288/1
V = 348.57 L