Answer:
False
Explanation:
Chemists make a distinction between two different types of changes that they study—physical changes and chemical changes. Physical changes are changes that do not alter the identity of a substance. Chemical changes are frequently harder to reverse than physical changes.
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
A 1.0 mol sample of he(g) at 25 is mixed with a 1.0 mol sample of Xe(g) at 50 C. What would be the changes in average kineeteic energy and the average speed of the Xe atoms that will occur as the mixture approaches thermal equilibrium?
Answer:
Explanation:
The average kinetic energy for an ideal gas is directly proportional to the temperature. The average kinetic energy of the gas is a measure of the temperature of the gas molecule
Also, the average speed is usually proportional to the square root of temperature.
Similarly, there is a noticeable increase in K.E and speed in regard to temperature but sometimes it is not usually proportional.
However, provided that there is more temperature in Xe as compared to He, then after the mixture of both takes place at equilibrium; the temperature tends to fluctuate between (25 - 50)°C
Thus, since there is a decrease in temperature in Xe, both the average kinetic energy as well as the speed too will also decrease.
Please help me thanks so much?!?!?
Answer:
color
Explanation:
Answer:
D
Explanation:
The five conditions of chemical change: color chage, formation of a precipitate, formation of a gas, odor change, temperature change and the others are just physical changes that would happen if you change containers, or let it evaporate.
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.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
Sodium 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.
A man receives a platinum ring from his fiancee. Before the wedding, he notices that the ring feels a little light for its size and decides to measure its density. He places the ring on a balance and finds that it has a mass of 3.15 grams. He then finds that the ring displaces 0.233 cm3 of water. Given that the density of pure platinum is 21.4 g/cm3, is this ring genuine
Answer:
The ring is probably not geniune.
Explanation:
To solve this problem we first need to calculate the density of the ring:
Density = mass / volumeThe mass is given by the problem, and we're able to assess the volume by keeping in mind Archimede's principle (the volume of water displaced by an object is equal to the object's volume).
Ring density = 3.15 g / 0.233 cm³ = 13.5 g/cm³Given that the ring density is significantly lower than the density of pure platinum, the ring is probably not geniune.
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Copper (II) chloride has a molar mass of 134.452 g/mol. What is the mass of 2.17 moles?
Answer:
292 g
Explanation:
Step 1: Given data
Molar mass of copper (II) chloride (M): 134.452 g/molMoles of copper (II) chloride (n): 2.17 molMass of copper (II) chloride (m): ?Step 2: Calculate the mass corresponding to 2.17 moles of copper (II) chloride
We will use the following expression.
m = n × M
m = 2.17 mol × 134.452 g/mol = 292 g
2.17 moles of copper (II) chloride weigh 292 g.
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?
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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
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
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 molWhat process forms an image in a mirror? Choices: A. absorbing light B. Reflecting light C. Refracting light D. Transmitting light
Where could convection currents form?
A. in a sand dune
B. on a pavement
C. in the atmosphere
D. in outer space
IM TIMED PLS HELP
Answer:
D. In the atmosphere
Explanation:
convection currents forms in the atmosphere
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.
What is the Molarity of a 2 liter solution containing 43.55 grams of K2504?
Answer:
M = 0.125 M
Explanation:
Given data:
Molarity = ?
Volume of solution = 2 L
Mass of K₂SO₄ = 43.55 g
Solution;
Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.
Formula:
Molarity = number of moles of solute / L of solution
Number of moles of solute:
Number of moles = mass/molar mass
Number of moles = 43.55 g / 174.26 g/mol
Number of moles = 0.25 mol
Molarity:
M = 0.25 mol / 2 L
M = 0.125 M
Please help me thanks!?!?!?
Answer:
its burning
Explanation:
can you please try to answer my latest question i need it badly please and thank you
Answer:
Burning.
Explanation:
Example:
Wood burns and produces smoke and ash.
1.81 g H2 is allowed to react with 10.2 g N2, producing 2.19 g NH3.What is the theoretical yield in grams for this reaction under the given conditions?
3H2(g)+N2(g)→2NH3(g)
The theoretical yield : = 10.251 g
Further explanationGiven
Reaction
3H₂(g)+N₂(g)→2NH₃(g)
1.81 g H₂
10.2 g N₂
2.19 g NH₃
Required
The theoretical yield
Solution
Find limiting reactant :
H₂ : 1.81 g : 2 g/mol = 0.905 mol
N₂ : 10.2 g : 28 g/mol = 0.364 mol
mol : coefficient
H₂ = 0.905 : 3 = 0.302
N₂ = 0.364 : 1 = 0.364
H₂ as a limiting reactant(smaller ratio)
Moles NH₃ based on H₂, so mol NH₃ :
= 2/3 x mol H₂
= 2/3 x 0.905
=0.603
Mass NH₃ :
= mol x MW
=0.603 x 17 g/mol
= 10.251 g
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.
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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
identify 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.
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:
an unknown substance has a mass of 57.4 g and occupies a volume of 34.3 ml. what is the density in g/ml?
Answer: 1.67
D=M/V
(D=57.4/34.3)= 1.67
application of baking powder
How do you figure out the # of
neutrons?
Answer:
Subtracting the number of protons from the atomic mass.
Answer:
Subtract Protons
Explanation:
Since the vast majority of atom's mass is found it's protons and neutrons, Subtracting the Number of Protons ( i.e. the atomic number ) from the atomic mass will give you the calculated number of neutrons in a atom,
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.
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
Learn more about wave below.
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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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Which is a nonmetal that becomes isoelectronic with argon
when it forms its most common ion?
Answer:sulfur
Explanation:
1. Each substance written to the right of the arrow in a chemical equation is a
(1 point)
O catalyst
O reactant
O precipitate
O product
Answer: product
Explanation:
Each substance written to the right of the arrow in a chemical equation is referred to as a product.
When writing a chemical equation, the substance that's written to the left of arrow in the equation is the reactants.
On the other hand which is the right side is the product.