Answer:
Physical change because it can go back to its original form.
Explanation:
How many molecules are in 650.0 g Mg(OH)₂ ?
Answer:
6.711 × 10²⁴ molecules Mg(OH)₂
General Formulas and Concepts:
Chemistry - Atomic Structure
Reading a Periodic TableUsing Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
650.0 g Mg(OH)₂
Step 2: Define conversions
Avogadro's Number
Molar Mass of Mg - 24.31 g/mol
Molar Mass of O - 16.00 g/mol
Molar Mass of H - 1.01 g/mol
Molar Mass of Mg(OH)₂ - 24.31 + 2(16.00) + 2(1.01) = 58.33 g/mol
Step 3: Convert
[tex]650.0 \ g \ Mg(OH)_2(\frac{1 \ mol \ Mg(OH)_2}{58.33 \ g \ Mg(OH)_2} )(\frac{6.022 \cdot 10^{23} \ molecules \ Mg(OH)_2}{1 \ mol \ Mg(OH)_2} )[/tex]
= 6.71061 × 10²⁴ molecules Mg(OH)₂
Step 4: Check
We are given 4 sig figs. Follow sig fig rules.
6.71061 × 10²⁴ molecules Mg(OH)₂ ≈ 6.711 × 10²⁴ molecules Mg(OH)₂
What masses of KCl and H2O are needed to make 250 g of 5.00 % solution?
____ g of KCl
____ g of H2O
Answer:
w/w means weight/weight
Therefore, in a 250 g of solution, 5% needs to be KCl,
i.e. 5% x 250 = 12.5 g of KCl is needed.
The masses of KCl and H2O are needed to make 250 g of 5.00 % solution is 12.5 g of KCl and 237.50 g of H2O.
Calculation of the masses:Since there is the solution of 250 g of 5.00 % solution
So, here
Mass of KCl is = 5% of 250 = 12.5 g
And, the mass of H2O is
= 250 - 12.5g
= 237.50 g
Hence, The masses of KCl and H2O are needed to make 250 g of 5.00 % solution is 12.5 g of KCl and 237.50 g of H2O.
Learn more about mass here: https://brainly.com/question/18470727.
How does chemistry affect cancer?
A. Chemicals can both cause and fight cancer
B. Chemicals can cure almost any cancer
C. Chemicals rarely cause cancer
D. Chemicals cause cancer in chemists more often than in other people
which of the following is an example of
a physical property?
Answer:
physical property is property that you can touch, smell as it is bumpy it smells like eggs.
Explanation:
YW
Answer:
Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.
Explanation:
A geologist studies rocks. Which of Earth's spheres would a geologist be most interested in?
Answer:
Lithosphere
Explanation:
Answer:
ether the crust or lithosphere
Explanation:
Chlorine (Cl) is 76% chlorine-35 and 24% chlorine-37. Determine the average atomic mass of chlorine. Show/Explain work.
Answer:
Average atomic mass of chlorine is 35.48 amu.
Explanation:
Given data:
Percent abundance of Cl-35 = 76%
Percent abundance of Cl-37 = 24%
Average atomic mass = ?
Solution:
Average atomic mass = (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass) / 100
Average atomic mass = (76×35)+(24×37) /100
Average atomic mass = 2660 + 888 / 100
Average atomic mass = 3548/ 100
Average atomic mass = 35.48 amu
Average atomic mass of chlorine is 35.48 amu.
Boron has two isotopes. Boron-10 which has a mass of 10.0129 and Boran-11 with a mass of 11.0093 occurs 52.69% of the time and B - 11 47.31% of the time. What is the average atomic mass of boron?
Help me
Answer:
Copper, a metal known since ancient times, is used in electrical cables and pennies, among other things. ... Calculate the average atomic mass of copper. ... The atomic masses of the two stable isotopes of boron 10B (19.78%) and 11B (80.22%) are 10.0129 amu ... (.1978)(10.0129 amu) + (.8022)(11.0093 amu) =10.81 amu.
Explanation:
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HELP!!! 30 POINTS!!!
Explanation:
[tex]periodic \: law[/tex]
It's correctAnswer
you already got it
Explanation:
How does granite differ from gabbro in coloring and
silica content?
A. Granite is lighter colored with higher silica
content.
B. Granite is darker colored with lower silica
content.
C. Granite is darker colored with higher silica
content.
D. Granite is lighter colored with lower silica
content.
Explanation:
Igneous rocks are formed by the crystallisation of a magma. The difference between granites and basalts is in silica content and their rates of cooling. A basalt is about 53% SiO2, whereas granite is 73%. Intrusive, slowly cooled inside the crust.
Please help me I. Eg you
Answer:
fehrf beviubeibchvbiscv kie v sjb rlj jsrubw
Explanation:
what are the reactants in a cheese sandwich
Answer:
cheese and bread
Explanation:
2 bread 1 cheese = cheese sandwich
A student performed the experiment in this module but failed to follow the procedure exactly, keeping the crucible completely covered during the entire heating and cooling processes. Be specific.
1. Explain the probable effect of this procedural change on the experimental results.
2. Would the student's calculated percent water in the hydrate be high, low, or unaffected? Briefly explain
Answer:
This question is incomplete
Explanation:
This question is incomplete but the answer to the question can be correctly predicted from the available information from the question.
1. If a "container" (in this case a crucible) is closed throughout a heating experiment. Then it must be noted that water vapor will not be able to escape during the course of the experiment. The water vapor will form a "cloud" of water droplets under the cover of the crucible. And when this crucible is cooled, this water droplets return back to the content/substance inside the crucible.
2. When compared with the initial amount of water present in the substance in the crucible, the percentage of water "left" in the hydrate or substance in the crucible would be high. This is because the water vapor that was suppose to leave the crucible did not leave because the crucible was closed (thus causing very low amount of water vapour to leave).
Because of the student error, the percent water of crystallization value the hydrate will be lower than its actual value.
What is evaporation?Evaporation is the process by which a liquid changes spontaneously to vapor.
In the experiment to determine percentage water of crystallization, the crucible is left open to ensure all the water molecules are removed by evaporation.
However,, since the student did not remove the crucible cover during heating, some water molecules will not be able to escape completely, but will return back to the salt.
Hence, the percent water of crystallization value the hydrate will be lower because the of mass of the anhydrous salt will be higher than its actual value.
Learn more about percent water of crystallization at: https://brainly.com/question/7805021
Who was known as the ‘laughing philosopher’?
Answer:
Democritus
Explanation:
Answer:
Democritus
Explanation:
They called him that because of his cheerfulness and how he treated people .
Hoped I helped-
Sleepy-
An open flask sitting in a lab fridge looks empty, but it is filled with a mixture of gases called air. Calculate the number of molecules of gas the flask contains if the flask volume is 2.50 L , and the air is at standard temperature and pressure (STP).
Answer: The number of molecules of gas the flask contains is [tex]0.674\times 10^{23}[/tex]
Explanation:
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 1 atm (STP)
V = Volume of gas = 2.50 L
n = number of moles = ?
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature = 273K (STP)
[tex]n=\frac{PV}{RT}[/tex]
[tex]n=\frac{1atm\times 2.50L}{0.0821 L atm/K mol\times 273K}=0.112moles[/tex]
According to Avogadro's law:
1 mole of gas at STP contains =[tex]6.023\times 10^{23}[/tex] molecules
Thus 0.112moles of gas at STP contains = [tex]\frac{6.023\times 10^{23}}{1}\times 0.112=0.674\times 10^{23}[/tex] molecules
The number of molecules of gas the flask contains is [tex]0.674\times 10^{23}[/tex]
as more discovers were made, whittaker proposed classifying orginsims into five _____
Answer:
As more discovers were made, Whittaker proposed classifying organisms into five Kingdoms
Omar heated a small piece of calcium carbonate. It gave off carbon dioxide gas, solid calcium oxide was left behind.write equation.
Answer:
CaCO[tex]_{3s}[/tex] → CO[tex]_{2g}[/tex] + CaO[tex]_{s}[/tex]
Explanation:
Given reactants:
Omar heated small piece of calcium carbonate
Product;
it gave off carbon dioxide gas and solid calcium oxide;
Problem,
Equation of the reaction;
Solution:
Calcium carbonate → Carbon dioxide + Calcium oxide
CaCO[tex]_{3s}[/tex] → CO[tex]_{2g}[/tex] + CaO[tex]_{s}[/tex]
Which of the following contains The greatest number of representative particles: 1 mole of water molecules, 1 mole of copper atoms, or 1 mole of sodium chloride ions?
a. 1 mole of copper atoms
b. 1 mole of sodium chloride ions
c. 1 mole of water molecules
d. none, they are all the same
Answer:
1 mole of sodium chloride ions
Explanation:
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Which is a valid reason why total dissolved solids (TDS) cannot be accurately calculated by conductivity alone?
Global warming has significantly increased the conductivity of water.
Big blobs of algae do not conduct electricity.
Fish poop changes the conductivity.
Ionic compounds may behave differently based on ion characteristics (e.g. charge or size).
Some dissolved solids may be nonelectrolytes.
Answer:
The correct option is the last option (Some dissolved solids may be nonelectrolytes)
Explanation:
Total dissolved solids (TDS) cannot be calculated by conductivity alone because conductivity involves ionic charges and there are solids that dissolve in water but do not carry ionic charges (and thus form non-electrolytes). Examples include sucrose (common sugar) and glucose. These two solids will dissolve in water but would not form ions that will carry ionic charges which are responsible for conductivity. Thus, if TDS only depends solely on conductivity, then a solution that contains dissolved sucrose will be wrongly accounted for as the sucrose will be omitted from the dissolved substances.
A valid reason why total dissolved solids (TDS) cannot be accurately
calculated by conductivity alone because some dissolved solids may be
non-electrolytes.
Conductivity means the ability of electric current to pass through a
substance and an electrolyte has a high conductivity when dissolved in
water.
Dissolved solids can't be measured by conductivity because not all
dissolved solids are electrolytes.
Read more on https://brainly.com/question/19457008
Theodor Schwann was a German scientist who wanted to understand how different types of cells worked and performed functions in different tissues. He was one of the first to theorize that all living things are made up of cells.
Rudolf Virchow was a German doctor who wanted to discover the origin of diseases. He accepted the idea that all living things are made up of cells and extended the idea to theorize that many diseases are the result of bacterial cells infecting the body.
The example described above suggests that
A.
scientific discoveries are never made by doctors.
B.
scientists always have the same goals when making related discoveries.
C.
German scientists were the first to disprove cell theory.
D.
people with different goals can make contributions to scientific knowledge.
D. People with different goals can make contributions to scientific knowledge
Both Schwann and Virchow had different thoughts and ideas. Schwann wanted to understand how cells worked - Virchow wanted to know the origin of diseases. Different goals.
Answer:
D
Explanation:
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Classify which compounds will dissolve in water and which ones will not dissolve in water.
a. Accetone
b. I-propanol
c. Hexane
d. Methanol
e. Decane
Answer:
Dissolves in water: Acetone, 1-propanol, Methanol
Do not dissolve in water: Hexane, Decane
Explanation:
From the principle that like dissolves like,polar substances will dissolve in polar solutions, while non-polar substances will dissolve in non-polar substances.
Water is a polar solution, therefore, polar substances will dissolve in it.From the given options:
Acetone is a polar molecule, therefore, it will dissolve in water.
1-propanol is a polar molecule, therefore, it will dissolve in water.
Hexane is a non-polar molecule, therefore, it will not dissolve in water.
Methanol is a polar molecule, therefore, it will dissolve in water.
Decane is a non-polar molecule, therefore, it will not dissolve in water
Which determines the reactivity of an alkali metal?
a. it's boiling and melting points
b. the shininess of its surface
c. the number of protons it has
d. it's ability to lose electrons
Answer:
d. It's ability to lose electrons
___ The energy of moving particles.
a. Chemical Energy
b. Radiant Energy
c. Mechanical Energy
Magnesium (Mg) has nine electrons. Which of the following shows the correct electron configuration for an atom of Mg?
2, 2, 5
7, 2
1, 8
2, 7
Answer:last one
Explanation:
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Answer:
1st one is...
Explanation:
The 1st one is change in size or shape. 2nd one is formation of precipitate. 3rd one is physical change. 4th one is formation of gas.
Why do you think your new patient, Elisa, is feeling tired all the time? Explain your ideas.
The most plausible reason why your new patient, Elisa, is feeling tired all the time is:
Her body is unable to break down the starch into glucoseAccording to the complete question, we can see that the cells which are in Elise's body are receiving oxygen and proteins, but they are not getting enough glucose, which can be gotten from breaking down starch.
As a result of this, we can see that the best diagnoses of why Elise is always getting tired is that she has diabetes because of the inability of the body to break down starch to provide enough glucose to the body.
Read more here:
https://brainly.com/question/18470980
find the volume of a gas at standard pressure if its volume at 1.9 atm is 80 ml?
given:
formula:
substitution:
answer:
Answer:
1.5 × 10² mL
Explanation:
Step 1: Given data
Initial pressure of the gas (P₁): 1.9 atmInitial volume of the gas (V₁): 80 mLFinal pressure of the gas (P₂): 1.0 atm (standard pressure)Final volume of the gas (V₂): ?Step 2: Calculate the final volume of the gas
For an ideal gas, we can calculate the final volume of the gas using Boyle's law.
P₁ × V₁ = P₂ × V₂
V₂ = P₁ × V₁/P₂
V₂ = 1.9 atm × 80 mL/1.0 atm
V₂ = 1.5 × 10² mL
Since the pressure decreased, the volume of the gas increased.
How many moles of H are present in 3 moles of carbon trihydride?
Answer:
4moles of carbon trihydride
