Answer:
272.31× 10²³ atom of strontium
Explanation:
Given data:
Number of moles of strontium = 45.22 mol
Number of atoms = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
45.22 mol × 6.022 × 10²³ atom / 1 mol
272.31× 10²³ atom
There are 25 elements found in living things. How many of these elements are found in some organisms but not all?
O1
O 6
O 19
O 25
A scuba diver begins to surface carrying a tank containing 4.0 L of a
gas at 730 mm Hg. What volume will the gas occupy at 760 mm Hg?
O A. 3.8 L
OB. 4.2 L
O C. 120 mm Hg
O D. 920 mm Hg
Answer:
3.8 L
Explanation:
From Boyle's law;
P1 V1 = P2 V2
P1 = initial pressure = 730 mm Hg
P2 = final pressure = 760 mm Hg
V1= Initial volume = 4.0 L
V2 = final volume = ?
V2 = P1 V1/P2
V2 = 730 × 4/760
V2 = 3.8 L
PLEASE HELP THIS IS WORTH 13 POINTS
Answer:
The chemical reaction is a Double Displacement
Explanation:
Balance the reaction of KOH + AlCl3 = KCl + Al(OH)3
During ionic bonding, there is a transfer of electrons...
O from one metallic element to a different metallic element
O from one nonmetallic element to a different nonmetallic element
O from one metallic element to a different metalloid
O from one metallic element to a different nonmetallic element
Answer:
from one metallic element to a different nonmetallic element
Explanation:
For example NaCl is ionic compound in which Na metal donate electron to Cl non metal
Which statement best describes what an ocean tide is?
A A change in water level that makes a high tide higher
B A change in water level at the shoreline that is being caused by the gravitational pull of the Moon
C A change in water level at the shoreline that is being caused by the gravitational pull of the Sun
D A change in water level that makes a low tide lower
Answer: B
Explanation: high tides and low tides are usually caused by the moon. The moons gravitational pull generates something called the tidal force. I’m not gonna go deep into this but yeah I think the answer is B
Answer:
:)
Explanation:
0.0721 moles of a compound have a mass of 31.008 grams. What is the molar mass?
(please show work and provide an explanation!)
Answer:
divide the moles by gram to get molar mass
use calculator and get yo ans
explain why the properties of a reactant can be different from the properties off the products of the reaction
Answer:
The reactants and products in a chemical reaction contain the same atoms, but they are rearranged during the reaction. As a result, the atoms end up in different combinations in the products. This makes the products new substances that are chemically different from the reactants.
Explanation:
A neutral atom (atomic number > 1) has
(a) electron and proton
(b) neutron and electron
(c) neutron, electron and proton
(d) neutron and proton.
Can someone help?? This is really hard.
Answer:
See Explanation
Explanation:
Let us consider the first two reactions, the initial concentration of CO was held constant and the concentration of Hbn was doubled.
2.68 * 10^-3/1.34 * 10^-3 = 6.24 * 10^-4/3.12 * 10^-4
2^1 = 2^1
The rate of reaction is first order with respect to Hbn
Let us consider the third and fourth reactions. The concentration of Hbn is held constant and that of CO was tripled.
1.5 * 10^-3/5 * 10^-4 = 1.872 * 10^-3/6.24 * 10^-4
3^1 = 3^1
The reaction is also first order with respect to CO
b) The overall order of reaction is 1 + 1=2
c) The rate equation is;
Rate = k [CO] [Hbn]
d) 3.12 * 10^-4 = k [5 * 10^-4] [1.34 * 10^-3]
k = 3.12 * 10^-4 /[5 * 10^-4] [1.34 * 10^-3]
k = 3.12 * 10^-4/6.7 * 10^-7
k = 4.7 * 10^2 mmol-1 L s-1
e) The reaction occurs in one step because;
1) The rate law agrees with the experimental data.
2) The sum of the order of reaction of each specie in the rate law gives the overall order of reaction.
A small, hard-shelled fossil that resembles a modern-day ocean organism was found
in the desert.
As
What can geologists conclude about this desert?
These shelled organisms migrated from the ocean to the desert.
Prehistoric man enjoyed eating shelled organisms in the desert.
A glacier once moved across the desert sands.
The desert was once covered by ocean water.
Answer:
The desert was one covered by ocean water.
Explanation:
Calculate the maximum
mass of magnesium oxide
that can be made from
2.4g of magnesium and
2.4g of oxygen.
1
1
2Mg + 0, → 2Mgo
Answer:
Mass = 3 g
Explanation:
Given data:
Mass of magnesium = 2.4 g
Mass of oxygen = 2.4 g
Mass of magnesium oxide formed = ?
Solution:
Chemical equation;
2Mg + O₂ → 2MgO
Number of moles of oxygen:
Number of moles = mass / molar mass
Number of moles = 2.4 g/ 32 g/mol
Number of moles = 0.075 mol
Number of moles of magnesium:
Number of moles = mass / molar mass
Number of moles = 2.4 g/ 24 g/mol
Number of moles = 0.1 mol
now we will compare the moles of magnesium oxide with both reactant.
Mg : MgO
2 : 2
0.075 : 0.075
O₂ : MgO
1 : 2
0.1 : 2/1×0.1 = 0.2
Mass of magnesium oxide:
Mass = number of moles × molar mass
Mass = 0.075 mol × 40 g/mol
Mass = 3 g
Count the atoms in this common formula for the explosive TNT
2C7H5(NO2)3
Answer:
Explanation:
7 carbon atoms, 6 hydrogen atoms,9 NO2 atoms
7+6+9=22
2(22)=44
44 atoms
1. What type of reaction is this?
H2O + H2 + O2
A. Synthesis
B. Decomposition
C. Combustion
D. Single Replacement
E. Double Replacement
I say synthesis
Answer:
B if you meant [tex]H_{2}O[/tex]->[tex]H_{2} +O_{2}[/tex]
Explanation:
A. Synthesis: reaction where two or more reactants combine to form one product. A+B->AB
B. Decomposition: reaction where a single compound reacts to form more than one product. AB-> A+B
C. Combustion: any reaction in which a substance reacts with oxygen gas. (needs [tex]O_{2}[/tex])
D. Single replacement: a type of reaction where one element replaces a similar element within a compound. Reaction is always an element and a compound.
E. Double replacement: a type of reaction where the ions of two compounds exchange places in an aqueous solution to form two new compounds. AB+CD->AD+CD
What is the mass number of an element that has 6 protons, 8 neutrons, and 6 electrons?
Answer:
14
Explanation:
the mass number = protons number +neutrons number
so..
6+8=14
3 common uses for salt
Answer:
Salt has long been used for flavoring and for preserving food. It has also been used in tanning, dyeing and bleaching, and the production of pottery, soap, and chlorine. Today, it is widely used in the chemical industry.
Where is our Solar System located?
Answer:
In space ( the sun and it's atmospheres )
Liquid waste that exits the body is _____________ and solid waste is ___________.
A. Feces, Urine
B. Urine, Feces
C. Lymph, Feces
D. Blood, Lymph
Answer:
The answer is B. Urine, Feces
Explanation:
Answer:
b.urine ,feces
.................
give the number of protons and neutrons in the nucleus of the following atoms
when an element has 238 mass number and 92 atomic number give the number of protons and neutrons in the nucleus
The number of protons and neutrons in the nucleus : 92 and 146
Further explanationGiven
Mass number = 238
Atomic number = 92
Required
Protons and neutrons
Solution
Mass number=number of protons + neutrons
Atomic number=number of protons=number of electrons
Atomic number = 92⇒number of protons=92
Number of neutrons = mass number - atomic number
Number of neutrons = 238 - 92 = 146
How many copper(I) ions (atoms of Cu 1+ ) are in a sample of copper(I) sulfate that weighs 35.4 grams?
Answer:
copper has 2+ ions in a sample of copper
Given the reaction: 4NH3 + 502 4NO + 6H2O
What is the total number of moles of NO produced when
1.0 mole of O2 is completely consumed?
Answer:
[tex]\frac{4}{5}[/tex] moles
Explanation:
The reaction equation is given as:
4NH₃ + 5O₂ → 4NO + 6H₂O
The number of moles of O₂ that completely reacted is given as 1 mole
To solve this problem, we are going to use a stoichiometric approach from the balanced reaction equation:
5 moles of O₂ will react completely to produce 4 moles of NO
1 mole of O₂ will therefore react to produce x mole of NO
5x = 4
x = [tex]\frac{4}{5}[/tex] moles of NO
Answer: 0.80 mole
Explanation:
Why are the halogen elements so dangerous in their uncombined forms?
Answer:
Halogen elements are dangerous in their uncombined forms because they are very reactive.
Explanation:
Hope this helps you! ^^
Halogens, including such chlorine or bromine, pose an environmental and occupational risk to the lungs and other organs.
What are halogens?The halogens are a group of five or six chemically related elements in the periodic table: fluorine, chlorine, bromine, iodine (I), and astatine.
Tennessee, an artificially created element, may also be a halogen. This group is known as group 17 in modern IUPAC nomenclature.
Halogens are unique in that they have seven valence electrons, making them extremely reactive. Valence electrons are the electrons involved in chemical reactions and are contained in the outer shell.
Fluorine is one of the most reactive elements known to man. Halides are simple halogen-containing compounds. Fluorine gas is lethal. Even breathing air containing 0.1% fluorine can result in death.
Thus, the halogen elements so dangerous in their uncombined forms.
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Describe how a measuring cylinder can be used to measure the volume of gas produced
Donde están ubicados los componentes básicos de una reacción química
Las sustancias a la izquierda de la flecha en una ecuación química se denominan reactivos. Un reactivo es una sustancia que está presente al comienzo de una reacción química. Las sustancias a la derecha de la flecha se denominan productos.
Which form of energy does a plant store when light is transformed during photosynthesis?
A.chemical energy
B.thermal energy
C.mechanical energy
D.electrical energy
Answer:
A. chemical energy
Explanation:
En un matraz, disponemos de 100 g de gas oxígeno que se encuentran a 1 at de presión y 273 K de temperatura. Calcular : a) el número de moles de gas oxígeno contenidos en el matraz ; b) el número de moléculas de oxígeno ; c) el número de átomos de oxígeno ; d) el volumen ocupado por el oxígeno. Masa atómica del oxígeno = 16.
Answer:
Explanation:
Dado que:
masa de oxígeno gaseoso = 100 g
presión = 1 atm
temperatura = 273 K
(a)
número de moles de oxígeno contenidos en el matraz = masa de oxígeno / masa molar de oxígeno
= 100 g / 16 gmol⁻¹
= 6.25 moles
(b) El número de moléculas de oxígeno es el siguiente:
Dado que 1 mol de oxígeno gaseoso contiene 6.023 * 10²³ moléculas de oxígeno.
Entonces, 6.25 moles contendrán:
= (6.25 × 6.023 * 10²³) moléculas de oxígeno.
≅ 3.764 × 10²³ moléculas de oxígeno.
(c) El número de átomos de oxígeno es:
= 2 × 3.764 × 10²³
= 7.528 × 10²³ átomos de oxígeno
(d) Usando la ecuación de gas ideal
PV = nRT
El volumen ocupado por el oxígeno = [tex]\dfrac{nRT}{P}[/tex]
Volumen ocupado por oxígeno = [tex]\dfrac{ 6.25 * 8.314 *273}{1}[/tex]
Volumen ocupado por oxígeno= 14185.76 m³
1.
Explain what changes occur in particle motion, temperature,
and state of a pure substance when thermal energy is added
or removed.
Type your answer here
Answer:
Thermal energy is heat energy.
When it is removed, the temperature of particle decreases due to decrease in the internal energy involving that particle.
Motion of the particle decreases due to decrease in kinetic energy caused by reduction in the internal energy.
The state of the particle changes from that current state e.g liquid or gas to a solid state due to increase in the latent heat of vapourisation.
With thermodynamics we can find that by giving energy to a substance the temperature increases and after a certain value it can change from solid to liquid and vapor state
In the opposite case, as the energy of a substance decreases, the temperature decreases and goes from a gaseous state to a liquid and a solid.
Thermodynamics study the changes that substances have as their energy changes, finding macroscopic relationships such as temperature, state, pressure and volume.
The temperature of a substance is a measure of the internal energy of the particles and the thermodynamic state of a substance can be solid, liquid or gaseous depending on whether the shape and volume is maintained.
Let's analyze what happens when we increase the energy of a substance.
In this case, the particles that form has more energy, so the temperature of the substance increases, if the energy is enough to break any bonds, the substance can go from the solid state to the liquid and by continuing to increase the energy it can be break all the bonds going from the liquid to the gaseous state.
In the opposite case, when the energy of the particles decreases, it has smaller movements, therefore its temperature decreases and if some bonds are formed, the substance stops from the gaseous state to the liquid state and if the energy continues to decrease, more bonds are formed passing the liquid state to solid.
In conclusion, with the change in energy, the temperature changes in the same direction and after a certain value it can go from solid to liquid and as the temperature increases more it can go from liquid to gas.
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Word equation for Silver being added to sulphuric acid
Answer:
See the answer below
Explanation:
When silver is added to dilute sulphuric acid, no reaction would occur. However, silver reacts with hot and concentrated sulphuric acid to produce silver sulphate, sulphur dioxide, and water.
The equation of the reaction is as below:
silver + sulphuric acid --> silver sulphate + water + sulphur dioxide
[tex]2Ag(s) + 2 H_2SO_4(aq) -->Ag_2SO_4 (s) + 2 H_2O (l) + SO_2 (aq)[/tex]
950 J of energy is used to heat an unknown mass of copper from 20.0° C to 95.0° C. The specific heat of copper = 0.39 J/(g·°C).
What is the mass of the copper?
Answer:
32g
Explanation:
I just took the test and got it right
The mass of the copper is approximately 32.5 grams.
To find the mass of the copper, we can use the formula for heat:
Q = m * c * ΔT
where Q is the heat energy, m is the mass, c is the specific heat, and ΔT is the change in temperature.
In this case, we are given:
Q = 950 J (heat energy)
c = 0.39 J/(g·°C) (specific heat)
ΔT = 95.0°C - 20.0°C
= 75.0°C (change in temperature)
Substituting these values into the formula, we can solve for the mass (m):
950 J = m * 0.39 J/(g·°C) * 75.0°C
Dividing both sides of the equation by (0.39 J/(g·°C) * 75.0°C), we get:
m = 950 J / (0.39 J/(g·°C) * 75.0°C)
m ≈ 32.5 g
Therefore, the mass of the copper is approximately 32.5 grams.
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14.
Consider the following balanced chemical equation:
P205
3 H2O → 2 H3PO4
Calculate the mass of hydrogen phosphate, H3PO, that will be produced from 105.9 g of P,Os.
Answer:
Mass = 72.52 g
Explanation:
Given data:
Mass of hydrogen phosphate produced = ?
Mass of P₂O₅ react = 105.9 g
Solution:
Chemical equation:
P₂O₅ + 3H₂O → 2H₃PO₄
Number of moles of P₂O₅:
Number of moles = mass/molar mass
Molar mass of P₂O₅ 283.9 g/mol
Number of moles = 105.9 g/ 283.9 g/mol
Number of moles = 0.37 mol
Now we will compare the moles of P₂O₅ with H₃PO₄ from balance chemical equation.
P₂O₅ : H₃PO₄
1 : 2
0.37 : 2/1×0.37= 0.74 mol
Mass of H₃PO₄ :
Mass = number of moles × molar mass
Mass = 0.74 mol × 98 g/mol
Mass = 72.52 g
A student rubbed a plastic comb with a piece of silk cloth. She held the comb near running water and saw that the stream of
water moved toward the comb.
Why did the stream of water move toward the comb?
A Rubbing the comb caused it to get hot so it repelled the water.
O B. Rubbing the comb caused charges to build up, so it repelled the water.
C. Rubbing the comb caused it to become magnetized, so it attracted the water.
O D. Rubbing the comb caused static electricity to build up, so it attracted the water.
Answer:
c
Explanation:
c
Answer:
Rubbing the comb caused static electricity to build up, so it attracted the water.