Answer:
solar flair I think I'm not sure
In a chemical change
A. materials retain their properties.
B. materials change their properties.
C. new materials do not form.
D. new materials formed are always in liquid form.
Answer:
B. materials change their properties.
Explanation:
In a chemical change, materials often change their properties because a re-arrangement of atoms takes place.
A chemical change is one in which new kind of matter is formed.
It is always accompanied by energy changes.
Chemical changes are not reversible. They lead to the production of new kinds of matter It involves mass changesRequires considerable amount of energySodium metal (Na) reacts explosively with water to form sodium hydroxide (NaOH) and hydrogen gas. How many moles of sodium are needed to produce 154 moles of hydrogen gas? (Hint: Balance the equation.)
Answer:
308 moles of sodium
Explanation:
The balanced equation for the chemical reaction between sodium metal (Na) and water (H₂O) is the following:
2 Na(s) + 2 H₂O → 2 NaOH(aq) + H₂(g)
From the equation, we can see that 2 moles of Na react with 2 moles of H₂O to give 2 moles of NaOH and 1 mol of H₂ (hydrogen gas). So the stoichiometric mole ratio between Na and H₂ is: 2 mol Na/1 mol H₂. Thus, we multiply the mole ratio by the moles of H₂ to be produced to obtain the moles of Na required:
moles of Na required = 2 mol Na/1 mol H₂ x 154 moles H₂ = 308 moles Na
Therefore, 308 moles of sodium are needed to produce 154 moles of hydrogen gas.
For the reaction of ammonia (NH3) with oxygen (O2) to produce water and nitric oxide (NO), how many moles of water are produced when 2.2 moles of ammonia are reacted?
Answer:
3.3 moles of H₂O.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
4NH₃ + 5O₂ —> 6H₂O + 4NO
From the balanced equation above,
4 moles of NH₃ reacted to produce 6 moles of H₂O.
Finally, we shall determine the number of mole of H₂O produced by the reaction of 2.2 moles of NH₃. This can be obtained as follow :
From the balanced equation above,
4 moles of NH₃ reacted to produce 6 moles of H₂O.
Therefore, 2.2 moles of NH₃ will react to produce = (2.2 × 6)/4 = 3.3 moles of H₂O.
Thus, 3.3 moles of H₂O were obtained from the reaction.
HELP IT’S ABOUT TO BE DUE!
Which is a nonmetal that becomes isoelectronic with argon
when it forms its most common ion?
Answer:sulfur
Explanation:
Which refers to any disturbance that carries energy from one place to another? wave trough motion crest
Answer:
Wave
Explanation:
Wave refers to any disturbance that carries energy from one place to another.
What is wave?Wave refers to disturbance or variation that occur in a body travelling or in motion which travels from one medium to another by transmitting energy from one location which is the origin to another location without transporting matter.
Therefore, Wave refers to any disturbance that carries energy from one place to another
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Question 1
is a group of two or more atoms that is held together by bonds.
O A A metal
O B. An atom
O C. A molecule
D. An element
What process forms an image in a mirror? Choices: A. absorbing light B. Reflecting light C. Refracting light D. Transmitting light
Which statement defines the enthalpy of solution?
the total number of particles in a solution
the phase change from a solid to a liquid
o the difference in characteristics between reactants and products
the change in energy when one substance dissolves in another
Answer:
the change in energy when one substance dissolves in another
Explanation:
The enthalpy changes are the heat changes accompanying physical and chemical changes. Actually, an enthalpy change is the difference between the sum of the heat contents of products (final state) and sum of the heat contents of reactants (initial state).
There are basically two types of heat changes that accompanies are reaction which are:
Exothermic changes Endothermic changesTherefore, the change in energy when one substance dissolves in another defines the enthalpy of solution.
Enthalpy of solution is the heat liberated or absorbed when one mole of a substance (solute) is dissolved in a specified volume of solvent (water).
Where would a disease transmitted by person to person contact be most likely to spread quickly
Answer: inside
Explanation:
Answer:
direct and indirect contact
Explanation:
if you touch a doorknob right after an infected person than you make be exposed to the disease.
Describe the relationship between kinetic energy and the states of matter?
PLS HELP I DONT SCIENCE HELP ASAP HELP
Answer:
The kinetic molecular theory of matter states that: Matter is made up of particles that are constantly moving. All particles have energy, but the energy varies depending on the temperature the sample of matter is in. This in turn determines whether the substance exists in the solid, liquid, or gaseous state.
Explanation:
How much energy is required to raise the temperature of 10.7 grams of gaseous helium from 22.1 °C to 39.4 °C ?
Answer:
Q = 2640.96 J
Explanation:
Given data:
Mass of He gas = 10.7 g
Initial temperature = 22.1°C
Final temperature = 39.4°C
Heat absorbed = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree. Specific heat capacity of He is 14.267 J/g.°C
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 39.4°C - 22.1°C
ΔT = 17.3°C
Q = 10.7 g× 14.267 J/g.°C × 17.3°C
Q = 2640.96 J
Dwarf planets are smaller than planets. What is another way that dwarf planets are different?
Answer:
dwarf planets lack the gravitational forces needed to pull in and accumulate all of the material found in their orbits
Explanation:
When performing a multiplication or division calculation, significant figures in the calculated result are dictated by the ________of the measured numbers. The calculated result should have ________the measured number in the calculation with the fewest _______.
Answer:
Explanation:
When performing a multiplication or division calculation, significant figures in the calculated result are dictated by the significant figures of the measured numbers. The calculated result should have the same significant figure as the measured number in the calculation with the fewest significant figures.
According to the rule guiding significant figures during mathematical operations; when performing multiplications or divisions involving multiple numbers, the final answer should have the same significant figures as the number with the least significant figures.
For example: if 10.54 and 101.25 are multiplied, the final answer should have the same significant figure as 10.54 because this is the number with the least significant figure among the numbers involved in the entire operation.
10.54 has 4 significant figures while 101.25 has 5 significant figures. The final answer should, therefore, have 4 significant figures.
Thus; 10.54 x 101.25 = 1,067
Which term represents the number of electrons in the furthest energy level from the nucleus? (A) Latin (B) Valance Electron (C) Atomic Number (D) Capitalized
You want to compare the malleability of
two metals. Plan an investigation that would allow you to determine
which metal is more malleable .
The temperature and the strength of the metallic link are the two most crucial variables that can impact how malleable a metal or alloy is.
What is metal ?A metal is a substance that has a shiny look when freshly processed, polished, or shattered, and conducts electricity and heat rather effectively. Generally speaking, metals are malleable and ductile.
The amount of pressure that a metal can sustain without breaking can be used to gauge its malleability. Varied metals have different degrees of malleability because of variations in their crystal structures.
The temperature of the metal and the strength of the metallic connection are the two parameters that define how malleable a metal or metal alloy will be.
Thus, The kind of the metallic connection can have a significant impact on how easily metal atoms can rearrange themselves.
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How do atoms in molecules bond?
plz answer I will give brainliest
Answer:
Via covalent bonds
Explanation:
Atoms in molecules are bonded together via covalent bonds. Covalent bonds are bonds that are formed by sharing of the valence electrons between two atoms.
The atoms can be of the same kind or of different kinds.
In most molecules, the two atoms are connected by sharing of their valence electrons. This way, each atom can attain stability by becoming isoelectric with the nearest noble gas. Some molecules are monoatomic, some are polyatomic.(The stands for a number the student is going to calculate.)
The ___________ stands for a number the student is going to calculate. Fill in the missing part of this equation.
(87. 1/mmole. C). ______= _____ kJ/mol.C
Answer:
1000 kJ.mmole / 1000 J.mole
Explanation:
To solve this, we need to analyze the given data.
We have a number which is 87.1 J/mmole.C (I'm assuming it has the J at the beggining because if not, then you are missing some data) and the final result is kJ/mol.C
The only unit that has not changed in the process was the °C, while the mole and J change respectively. In this case, we need to know the conversion factor of mmole to mole and J to kJ.
In the case of a mole:
1 mole --------> 1000 mmole
In the case of Joule:
1 kJ ----------> 1000 J
So the first thing we will do is to change from J to kJ:
87.1 J * 1 kJ / 1000 J = 0.0871 kJ
Now let's convert mmol to mole:
0.0871 kJ/mmole.C * 1000 mmole / 1 mole = 87.1 kJ/mole.C
As you can see, there's is practicly no change at all with the units, so putting all together it would be:
87.1 J/mmole.C * 1000 kJ.mmole / 1000 J.mole = 87.1 kJ/mole.°CHope this helps
How many formula units of CaO are in 32.7 g of CaO?
Answer:
3.51× 10²³ formula units
Explanation:
Given data:
Mass of CaO = 32.7 g
Number of formula units = ?
Solution:
First of all we will calculate the number of moles.
Number of moles = mass/molar mass
Number of moles = 32.7 g/ 56.1 g/mol
Number of moles = 0.583 mol
Number of formula units:
1 mole = 6.022 × 10²³ formula units
0.583 mol × 6.022 × 10²³ formula units / 1 mol
3.51× 10²³ formula units
The number 6.022 × 10²³ is called Avogadro number.
All drugs must interact specifically with a biological macromolecule to produce biological action؟
T /F
Answer:
True
Explanation:
A drug is "a medicine or other substance which has a physiological effect when ingested or otherwise introduced into the body"(Oxford dictionary).
In the body, there are numerous macromolecules that perform various functions. These macromolecules often function as the target molecules to which different drugs may be bound.
A drug functions by binding strongly to a macromolecule with which it interacts in order to produce the desired biological action.
Which of the following elements is NOT a metal?
A) arsenic
B) indium
C) iridium
D) lithium
E) lutetium
Answer:
arsenic don't mind does it have to be longer
The statement, that describes the elements is not a metal is "arsenic.
"What is a metal?Metals are shiny, opaque elements that transfer heat and electricity well. They are malleable and easily lose electrons to produce positive ions (cations).
Arsenic is the third element in the periodic table's fifteenth column. It is a metalloid or semi-metal because it possesses chemical and physical properties that are transitional between a metal and a non-metal.
Hence the correct option is A.
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a dragster in a race accelerated from rest to 60 m/s by the time it reached the finish line. the dragster moved the distance from start to finish in 8.3 seconds. what is the dragsters acceleration?
i’ll mark brainliest!!
Answer:
7.23m/s²
Explanation:
Given parameters:
Initial velocity = 0m/s
Final velocity = 60m/s
Time taken = 8.3s
Unknown:
Acceleration of the dragsters = ?
Solution:
Acceleration is defined as the rate of change of velocity with time taken.
So;
Acceleration = [tex]\frac{Final velocity - Initial velocity }{time}[/tex]
Acceleration = [tex]\frac{60 - 0}{8.3 }[/tex] = 7.23m/s²
2. The heat from an acetylene torch is produced by burning acetylene (C2H2) in oxygen.
2C2H2 + 502 --> 4CO2 + 2H20
When 2.40mol C2H2 reacts with 7.40mol O2,
a. Which reactant is the limiting reactant?
b. How many grams of water can be produced by the reaction?
c. How many moles of the excess reactant remains?
I NEED THIS ANSWER QUICKLY IF YOU CAN ONLY DO B THATS FINE THANK YOU
Answer: a. C₂H₂
b. 43.2 g
c. 1.4 moles
Explanation: In a chemical reaction, when a reagent is completely consumed and limits the product formed is called Limiting Reagent. The reactant that is left is the Excess Reactant.
For the burning of acetylene:
[tex]2C_{2}H_{2}+5O_{2} \rightarrow 4CO_{2}+2H_{2}O[/tex]
a. An easy way to determine which reactant is limiting, is to divide the number of moles of each reactant by the coefficient in the balanced reaction. The component that gives the smallest number is the limiting reagent.
The ratio for acetylene is
[tex]\frac{2.4}{2}[/tex] = 1.2
For oxygen:
[tex]\frac{7.4}{5}=[/tex] 1.48
So, the limiting reactant is acetylene.
b. From the balanced reaction, for each 2 moles of acetylene is consumed, 2 moles of water is produced. Then, for 2.4 moles, it will be produced 2.4 moles of water.
Mol is mass in grams divided by molar mass of the component.
[tex]n=\frac{m}{M}[/tex]
Molar mass of water is M = 18 g/mol.
Then, mass of water produced:
m = n.M
m = 2.4(18)
m = 43.2 g
With 2.4 moles of acetylene, it will be produced 43.2 grams of water.
c. For each 2 moles of acetylene consumed, 5 moles of oxygen is also consumed. So, for 2.4 moles:
2 moles = 5 moles
2.4 moles = n
[tex]n=\frac{2.4*5}{2}[/tex]
n = 6 moles
For 2.4 moles of acetylene, it is consumed 6 moles of oxygen. Then, the excess is
7.4 - 6 = 1.4
The excess reactant remaining is 1.4 moles of oxygen.
9. Calculate the specific heat capacity of titanium if a 43.56 g sample absorbs 0.476 kJ as its temperature changes from 20.5 oC to 41.2 oC.
Answer:
c = 0.528 J/g.°C
Explanation:
Given data:
Mass of titanium = 43.56 g
Heat absorbed = 0.476 KJ = 476 j
Initial temperature = 20.5°C
Final temperature = 41.2°C
Specific heat capacity = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 41.2°C - 20.5°C
ΔT = 20.7 °C
476 J = 43.56 g × c × 20.7 °C
476 J = 901.692 g.°C × c
c = 476 J / 901.692 g.°C
c = 0.528 J/g.°C
6. 7. A hyperbaric chamber has a volume of 200. L. (a) How many moles of oxygen are needed to fill the chamber at room temperature (23°C) and 3.00 atm pressure? b) How many grams of oxygen are needed? (Hint: Since moles have been asked, which equation has the moles listed in the equation. Use that to solve this problem. Also don’t forget to use the equation 1 mole = Formula weight or Molecular weight to calculate the grams of O2).
Answer:
a) 24.7 mol
b) 790 g
Explanation:
Step 1: Given data
Volume of the chamber (V): 200. LRoom temperature (T): 23 °CPressure of the gas (P): 3.00 atmStep 2: Convert "T" to Kelvin
We will use the following expression.
K = °C + 273.15
K = 23°C + 273.15 = 296 K
Step 3: Calculate the moles (n) of oxygen
We will use the ideal gas equation.
P × V = n × R × T
n = P × V/R × T
n = 3.00 atm × 200. L/(0.0821 atm.L/mol.K) × 296 K = 24.7 mol
Step 4: Calculate the mass (m) corresponding to 24.7 moles of oxygen
The molar mass (M) of oxygen ga sis 32.00 g/mol. We will calculate the mass of oxygen using the following expression.
m = n × M
m = 24.7 mol × 32.00 g/mol = 790 g
An element has five isotopes. Calculate the atomic mass of this element using the information below. Show all your work. Using the periodic table, identify the element this is likely to be and explain your choice. (18 pts)
A) Isotope 1 – mass: 64 amu; percent abundance: 48.89%
B) Isotope 2 – mass: 66 amu; percent abundance: 27.81%
C) Isotope 3 – mass: 67 amu; percent abundance: 4.11%
D) Isotope 4 – mass: 68 amu; percent abundance: 18.57%
E) Isotope 5 – mass: 70 amu; percent abundance: 0.62%
Answer: Sol:-
Data provided in the question is :-
Atomic mass of isotope -1 = 64 amu
Atomic mass of isotope -2 = 66 amu
Atomic mass of isotope -3 = 67 amu
Atomic mass of isotope -4 = 68 amu
Atomic mass of isotope - 5 = 70 amu
Percentage abundace of isotope - 1 = 48.89 %
Percentage abundance of isotope -2 = 27.81 %
Percentage abundance of isotope - 3 = 4.11%
Percentage abundance of isotope-4 = 18.57%
Percentage abundance of isotope - 5 = 0.62 %
Formula used :-
Average atomic mass of an element =[ {(atomic mass of isotope-1 * percentage abundance of isotope-1) + ( atomic mass of isotope-2 * percentage abundance of isotope -2) + ( atomic mass of isotope -3 * percantege abundance of isotope-3 ) + ( atomic mass of isotope-4 * percentage abundance of isotope-4) + (atomic mass of isotope-5 * percentage abundance of isotope-5)} / 100]
Calculation :-
Put all the value in the formula :-
Average atomic mass of an element = [{(64 * 48.89) + (66 * 27.81) + (67 * 4.11) + (68 * 18.57) + (70 * 0.62)} / 100] amu
= [{(3128.96) + (1835.46) +(257.37) + (1262.76) + (43.4)} / 100] amu
= {(6528.04) / 100} amu
= 65.2804 amu
Average atomic mass of an element is = 65.2804 amu
Then this mass is approximatly equal to atomic mass of zinc so this element would be zinc
atomic mass of zinc = 65.38 \approx 65.2804 amu
Jupiter has about 317 times more mass than Earth. What can you infer from this
fact?
Answer:
That Jupiter's gravitational force is much stronger than Earth's gravitational force.
Convert
31.82 grams of ca(oh)2 to moles
3.2 moles of K2SO3 to grams
7.25x10^23 formula units of hcl to moles
46.6L of Cl2 gas to moles at STP
Answer:
0.43 moles Ca(OH)₂506.4 grams K₂SO₃1.20 moles HCl2.080 moles Cl₂Explanation:
-We convert Ca(OH)₂ grams to moles using its molar mass:
31.82 g ÷ 74.093 g/mol = 0.43 mol-We convert K₂SO₃ moles to grams using its molar mass:
3.2 mol * 158.26 g/mol = 506.4 g-One formula unit of HCl is HCl. We convert molecules to moles using Avogadro's number:
7.25x10²³ molecules ÷ 6.023x10²³mol/molecules = 1.20 mol-At STP, one mol of any gas occupies 22.4 L:
46.6 L * 1 mol / 22.4 L = 2.080 molidentify the equipment best suited for extinguishing each type of fire. Your choices are: fire extinguisher, overturned beaker, fire blanket.
Answer: The equipment best suited for extinguishing each type of fire are listed below:
--> Fire extinguisher: Large fire on the floor
--> Overturned beaker: Small benchtop fire
--> Fire blanket: clothing fire.
Explanation:
Fire outbreaks is a common event that can be prevented in a standard chemistry laboratory with the aid of fire safety equipments.
The method used by these equipments to extinguish fire is to suffocate the fire by obstructing the source of oxygen, by reducing the heat with the use of water and removing the fuel or oxygen source.
These fire safety equipments should be highly visible and easily accessible in a laboratory. Example of fire safety equipments includes:
--> Fire extinguisher: A laboratory personnel needs to be trained in the use of this since it's made up of different types. it can be used to extinguish ( put out) large fire on the floor.
--> Overturned beaker: this can be used to suffocate small fire on the bench which is also common in the laboratory.
-->Fire blanket: This should be used in the event that a person’s body or clothing catches fire.
In an MO (molecular orbital) scheme for CH4, Group of answer choices ..there are three equivalent bonding MOs of equal energy and one unique bonding MO. ..there are four equivalent bonding MOs of equal energy. ..there are two sets of doubly degenerate bonding MOs. ..there are four bonding MOs, each of different energy.
Answer:
there are three equivalent bonding MOs of equal energy and one unique bonding MO.
Explanation:
Let us recall that according to the principles of the molecular orbital theory, when a compound is formed, the number of bonding molecular orbitals must be equal to the number of antibonding molecular orbitals.
Now methane is formed from one carbon atom and four hydrogen atoms. There are four bonding molecular orbitals and four antibonding molecular orbitals.
Three out of the four bonding molecular orbitals are degenerate while one is unique.