Answer:
Pressure is often defined as a measure of force applied on an area, or over a unit area.
Explanation:
An isotope of cesium (cesium-137) has a half-life of 30 years. If 1.0 g of cesium-137 disintegrates over a period of 90 years, how many g of cesium-137 would remain?
Answer:
3 half-lives 7. An isotope of Cesium (Cesium-137) has a half life of 30 years. If 1.0 mg of cesium-137 disintegrates over a period of 90 years, how many mg of cesium-137 would remain? of sodium-25 is 60 seconds? : 3 minutes t=601 = 3 half-lives 5.0mg ~ 2.5 mg + 1.25mg →) 625 mg.
Explanation:
Hope this helps
where:
[tex]N_{0}[/tex] = Initial quantity of the sample = 1.0g
t = time in years of disintegration = 90 years
[tex]t\frac{1}{2}[/tex] = Half life of cesium isotope = 30 years
N(t) = Quantity of substance after disintegration = ?
Solving for N(t)N(t) = [tex]1 ( \frac{1}{2})^ \frac{90}{30}[/tex]
N(t) = [tex]1 (\frac{1}{2})^{3}[/tex]
N(t) = 0.125 grams
Therefore, the quantity of cesium-137 that would remain after disintegrating over a period of 90 years is 0.125 grams.
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The shape of the SO4 molecule is
Answer:
sndnmxixixisijwiw
Explanation:
jeejndn jzjaisisp
How often does the tip of and hour hand on a clock have the same velocity?
Answer:
Estoy triste, tuve que regalar a mi perro
1)
If I have 45 liters of helium in a balloon at 25°C and increase the
temperature of the balloon to 55° C, what will the new volume of the
balloon be?
Answer:
52.8 Liters
Explanation:
Gay-Lussacs law states that P1/T1 = P2/T2
if:
P1 = 45T1 (in Kelvins) = 25 + 273.1 =298.1P2= ?T2 = 55 + 273.1 = 328.1then:
45/298.1 = P2/328.1
P2 = 52.8
The new volume of the balloon is 52.8 Liters this can be calculated by using gas laws.
Charles law:Charles law states the volume occupied by a fixed amount of gas is directly proportional to its absolute temperature. It is given by
V₁/T₁ = V₂/T₂
What information do we have?
V₁ = 45 L
T₁ = 25 + 273.1 =298.1 K
T₂ = 55 + 273.1 = 328.1 K
To find:
V₂= ?
On substituting the values:
45/298.1 = V₂/328.1
V₂ = 52.8 L
Thus, the volume of the balloon is 52.8 liters.
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Determine the oxidation number of
Sulphur in Sodium thiosulphate
The oxidation number of Sulphur = +2
Further explanationGeneral formula for determining Oxidation Numbers :
1. The number of oxidation of single element atoms = 0. Examples of Ar, Mg, Cu, Fe, N₂, O₂, etc. = 0
Group I : +1
Group II : +2
H in compound = +1, except metal hydride compounds (Hydrogen which binds I or II groups) oxidation number H = -1, for example, LiH, MgH₂, etc.
2. Oxidation number O in compound = -2, except OF2 = + 2 and in peroxide (Na₂O₂, BaO₂) = -1 and superoxide, for example KO₂ = -1/2.
3 The oxidation number in a non-filled compound = 0,
The total amount of oxidation in ion = ion charge, Example NO₃⁻ = -1
Sodium thiosulphate - Na₂S₂O₃
Oxidation number Na = +1 ⇒x2 = +2
Oxidation number O = -2 ⇒x3 = -6
Oxidation number Na₂S₂O₃ = 0
2.Na+2.S+3.O=0
2.+1+2.S+3.(-2)=0
2+2S-6=0
-4+2S=0
2S=4
S=+2
2 NaOH (s) + CO2(g) → Na2CO3 (s) + H20 (I) How many grams of water can be produced with 1.85 moles of NaOH
Explanation:
Mole ratio of NaOH to H2O = 2 : 1
Moles of H2O = 1.85mol * (1/2) = 0.925mol.
Mass of H2O = 0.925mol * (18g/mol) = 16.65g.
Answer:
16.65 grams of water can be produced with 1.85 moles of NaOH.
Explanation:
Mole ratio of NaOH to H2O = 2 : 1
Number of moles of water = (1/2)×1.85= 0.925 moles
Molar mass of water (H2O) = 18g/mol
Mass of the right water = 18g/mol×0.925 mol=16.65 grams
Sulfur dioxide, SO2, is used in wine as an antioxidant, slowing the oxidation of ethanol
to ethanoic acid. To determine the SO2 content of a wine sample, sodium hydroxide
and sulfuric acid were added to ensure that all sulfur was present as SO2. A 20.00 mL
aliquot was then titrated against standardised iodine solution, using starch indicator.
Reaction occurred according to the equation:
SO2(aq) + 2H2O(l) + 12(aq) → 4H+ (aq) + 21- (aq) + SO42- (aq)
The end point was reached with 15.62 mL of 0.00501 M iodine solution. The
concentration (in M) of SO2 in the wine was ...
A)6.2 x 10-3
B)7.8 x 10-3
C)3.9 x 10-3
D)5.0 x 10-3
The concentration (in M) of SO₂ in the wine : c. 3.9 x 10⁻³
Further explanationGiven
Reaction
SO2(aq) + 2H2O(l) + I2(aq) → 4H+ (aq) + 21- (aq) + SO42- (aq)
Required
The concentration (in M) of SO2
Solution
Titration ⇒ mol SO₂ = mol iodine(I)
mol iodine :
=15.62 ml x 0.00501 M
=0.078256 mlmol
From equation, mol ratio of of SO₂ : I₂ = 1 : 1, so mol SO₂=0.078256
The concentration of SO₂(in 20 ml sample) :
M = n/V
M = 0.078256 mlmol/20 ml
M = 0.0039128
M = 3.9 x 10⁻³
The number of calories listed on a food label always refers to the number in the entire package
HELPP! What is ammonium nitrates freezing point ?
Answer:
Freezing points for water with freezing mixtures based on salt and ice: Ammonium Nitrate - Chrushed Ice or Snow in Water 1 part Ammonium Nitrate - 0.94 parts Ice/water : temperature -4 o C 1 part Ammonium Nitrate - 1.20 parts Ice/water : temperature -14 o C
Explanation:
Burning a marshmallow is an example of a
A. chemical change
B .no change
C. physical change
Answer:
A, chemical change
Explanation:
When marshmallows are toasted, a chemical change occurs. The sugar molecules in the marshmallow are being changed into carbon. Sugar can be changed into water molecules. When you toast marshmallows, the heat causes a chemical reaction producing water molecules which then evaporate, leaving the carbon behind.
2. Iron reacts slowly with hydrochloric acid to produce iron (II) chloride and hydrogen gas.
Fe + 2HCl FeCl2 + H2
What mass of hydrogen chloride is required to react with 3.56 g of Iron?
Mass of Hydrogen chloride : 4.672 g
Further explanationGiven
Reaction
Fe + 2HCl ⇒ FeCl2 + H2
3.56 g of Iron
Required
mass of Hydrogen chloride
Solution
mol of Iron (Ar = 56 g/mol) :
mol = mass : Ar
mol = 3.56 : 56
mol = 0.064
mol HCl from the equation :
= 2/1 x mol Fe
= 2/1 x 0.064
= 0.128
Mass HCl :
=mol x MW HCl
= 0.128 x 36.5
= 4.672 g
what is a physical quantity
How many molecules are in 20,484 grams of H2O?
Answer:
3.4027x10^-22
Explanation:
Based on the number of valence electrons indicated by its location in the periodic table ,which elements behavior would you predict to be closest to that of potassium (k)
Answer:
Na sodium or Rb rubidium
Explanation:
Because Na is present in first group all members of group 1 have 1 electron in valence shell and show similar properties.
The structure of an atom is
Answer:
Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged).
Where does gravity from planet Earth actually pull you toward?
7. The root structures on peanut plants that restore soil nutrients and fix nitrogen
Answer:
Like other legumes, peanut plants improve the soil by adding nitrogen, even as they grow tasty, nutritious nuts for this season's harvest. But peanuts need help as they take nitrogen from the air and "fix" it into the soil via their root systems.
Explanation:
How much volume (in cm3) is gained by a person who gains 12.3 lb of pure fat?
Answer:
So we are given with the mass while we are asked for the amount of volume. So this means, we must need an information on the density. From literature, the density of human fat is 0.918 g/cm³. Convert grams to lb by the conversion that 1,000 g = 2.2 lbs.
Density = 0.918 g/cm³ * (2.2 lbs/1,000 g) = 0.0020196 lb/cm³
Volume = Mass/Density = 12.2 lb / 0.0020196 lb/cm³
Volume = 6,040.8 cm³
Which of the following best explains why Reggie's books fell?
Explanation:
When Reggie's car turned eastward, his books continued heading northward, causing them to slide off the top of his car and fall.
were is the opshons.
Describe the atoms in matter as it changes from a gas to a liquid. ANSWER QUICK!! 90 POINTS IF ANSWER
Answer:
Clouds are water
Explanation:
When a gas gathers up into a cloud,the cloud starts to rain and water comes out of the cloud.
A 25.00 mL sample of an H2SO4 solution of unknown concentration is titrated with a 0.1322 M KOH solution. A volume of 41.22 mL of KOH is required to reach the equivalence point. What is the concentration of the unknown H2SO4 solution? Express your answer in molarity to four significant figures.
Answer:
[tex]0.1090\ \text{M}[/tex]
Explanation:
Volume of [tex]KOH[/tex] = 41.22 mL
Molarity of [tex]KOH[/tex] = 0.1322 M
Number of moles of [tex]KOH[/tex]
[tex]n=\text{Molarity}\times \text{Volume of }KOH\\\Rightarrow n=0.1322\times 41.22\times 10^{-3}\\\Rightarrow n=0.005449284\ \text{mol}[/tex]
2 moles of [tex]KOH[/tex] reacts with 1 mole of [tex]H_2SO_4[/tex]
So,
[tex]0.005449284\ \text{mol}[/tex] of [tex]KOH[/tex] reacts with M mole of [tex]H_2SO_4[/tex]
[tex]M=\dfrac{0.005449284}{2}=0.002724642\ \text{mol}[/tex]
Volume of [tex]H_2SO_4=25\times 10^{-3}\ \text{L}[/tex]
Concentration of [tex]H_2SO_4[/tex] is
[tex]M=\dfrac{0.002724642}{25\times 10^{-3}}\\\Rightarrow M=0.10898568\approx 0.1090\ \text{M}[/tex]
The concentration of the unknown [tex]H_2SO_4[/tex] solution is [tex]0.1090\ \text{M}[/tex].
How much heat do you need to raise the temperature of 100 g of aluminum from 30°C to 150°C?
Answer:
Heat energy can be calculated by using the specific heat of a substance multiplying it to the mass of the sample and the
change in temperature. It is expressed as:
Energy = mCAT
Energy = 100 (0.90) (150 - 30)
Energy = 10800 J
Mn(OH)3 what is it called
Answer:
Lets start by looking at the elements We had Mn= manganese OH= Hydroxide We have a subscript of 3 Hence Manganese III HydroxideAssuming a 25% efficiency, how many Calories would a horse need to consume to work at 1.0 hp for 2.0 hh ?
Answer:
E = 7.11 × [tex]10^{-7}[/tex] Cal
Explanation:
given data
efficiency = 25 %
solution
first we get here E by the power that is express as
p = [tex]\frac{E}{t}[/tex] ...........1
E = p × t
E = 1 × 2 × [tex]\frac{1hp}{746w} \times \frac{1hr}{3600 s}[/tex]
E = 7.447 × [tex]10^{-7}[/tex] J
and
Ein is get by efficiency
Ein = [tex]\frac{Eout}{\eta }[/tex] ..................2
Ein = [tex]\frac{7.447 \times 10^{-7}}{.25 }[/tex]
Ein = 29.788 × [tex]10^{-7}[/tex] J
so required energy is
E = 29.788 × [tex]10^{-7}[/tex] × [tex]\frac{1Cal}{4.184J}[/tex]
E = 7.11 × [tex]10^{-7}[/tex] Cal
How many molecules are equal to 89.23g of calcium oxide
Answer:
1.593 moles
Explanation:
Therefore, 1.593 moles are equal to 89.23 g of calcium oxide.
Answer:
9.64 × 10²³ molecules
Explanation:
Given data:
Mass of calcium oxide = 89.23 g
Number of molecules = ?
Solution:
First of all we will calculate the number of moles of calcium oxide.
Number of moles = mass/molar mass
Number of moles = 89.23 g/ 56.1 g/mol
Number of moles = 1.6 mol
Number of molecules;
1 mole contain 6.022 × 10²³ molecules
1.6 mol × 6.022 × 10²³ molecules / 1mol
9.64 × 10²³ molecules
The number 6.022 × 10²³ is called Avogadro number.
A student obtained a test tube with a suspension of white, slightly soluble calcium hydroxide in water. This system was at equilibrium as represented by the following equation:_______.
Ca(OH)2(s)Ca2(aq)+ 20H(aq)
Write the equilibrium constant expression for this reaction.
Answer:
K = [Ca²⁺] [OH¯]² / [Ca(OH)₂]
Explanation:
Equation for the reaction is given below:
Ca(OH)₂(s) —> Ca²⁺(aq) + 2OH¯(aq)
Equilibrium constant =?
Equilibrium constant (K) for a reaction is simply the ratio of the concentration of the products raised to their coefficient to the concentration of the reactants raised to their coefficient.
Thus, we can write the equilibrium constant (K) for the above reaction as follow:
Ca(OH)₂(s) —> Ca²⁺(aq) + 2OH¯(aq)
K = [Ca²⁺] [OH¯]² / [Ca(OH)₂]
A. A student was given an unknown sample of a pure metal to identify. Its mass was 116
g. He determined that 511 J of energy raised the temperature of the sample from 21.6°C
to 40.5°C. Based on his measurements, what kind of metal was the sample? (4 points)
Answer:
Silver
Explanation:
Given parameters:
Mass = 116g
Energy = 511J
Initial temperature = 21.6°C
Final temperature = 40.5°C
Unknown:
Specific heat capacity and the type of metal = ?
Solution:
To solve this problem, we need to find the specific heat capacity of the metal given,
H = m x c x Ф
H is the energy
m is the mass
c is the specific heat capacity
Ф is the change in temperature
511 = 116 x c x (40.5 - 21.6)
511 = 2192.4c
c = 0.233J/g°C
The specific heat capacity of silver is similar to this.
Answer:
READ THE EXPLAINATION
Explanation:
It says show your work.
40.5°C – 21.6°C = 18.9°C
So, the metal was raised 18.9 deg Celsius.
It took 511 J of energy to raise the metal 18.9 deg Celsius.
511/ 18.9 = 27.03
It takes 27.03 J to raise 116 g of the metal 1 degree.
27.03/116 = .233
It takes .233 J to raise 1 gram of the metal 1 degree.
Therefore, the specific heat capacity of the metal is .233 J
According to the Specific heat values table, Silver has a specific heat capacity of .233.
The metal is silver.
Of the following substances, only _____ has London dispersion forces as its only intermolecular force.
A) CH3OH B) NH3 C) H2S D) CH4 E) HCl
Explain the reasoning. (PLEASE EXPLAIN!!!!!!)
Answer:
A
Explanation:
a) C6H14, C8H18 – London-dispersion force
Since both substances have the same intermolecular force, the substances with the
larger molecular mass with have the higher boiling point. In this case, C8H18 will
have the higher boiling point.
b) C3H8 – London-dispersion force
CH3OCH3 –Dipole-dipole
The higher boiling point belongs to CH3OCH3 because is has the stronger
intermolecular force, dipole-dipole interaction.
c) CH3OH – Hydrogen bonding
CH3SH – Dipole-dipole interaction
Hydrogen bonding is the strongest intermolecular force, so CH3OH will have the
higher boiling point.
d) NH2NH2 – Hydrogen bonding
CH3CH3 – London-dispersion force
Hydrogen bonding is the strongest intermolecular force, so NH2NH2 will have the
higher boiling point.
The only intermolecular interaction present in the methane molecule is London dispersion forces.
The following points can be considered:
The electronegativity of the carbon and hydrogen is closer in values. Therefore the carbon to hydrogen bond in the methane molecule is not polar. The only intermolecular interaction present in the molecule is a weak London dispersion force.Methanol is having dipole-dipole interactions, hydrogen bonding interactions. Ammonia is a polar molecule and hence there are dipole-dipole interactions. Hydrogen sulphide possesses a change in the electronegativity of sulphur and hydrogen. So the molecule is polar in nature. The HCl molecule is polar in nature, possess dipole-dipole interactions.Therefore, the correct answer is D)CH4 that is methane.
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the gravitational force between two objects depends on the distance between the objects and each object?
Answer:
Gravitational force between two objects depends on: a. The weight of the objects c. The mass of each object b. The distance between the objects d. Both b and c Please select the best answer from the choices provided A B C D
✓d
Which of the following is a chemical change?
A) sugar dissolving in a cup of coffee
B) water evaporating
C) ice cream melting
D) carbon and oxygen reacting to form carbon dioxide