a reaction vessel contains a small piece of magnesium metal and air (20%) of which is oxygen gas. The mixture is ignited and burns with a burst of light and heat, producing solid magneisum oxide. The mass of mgO, however, is less than the initital mass of magnesium and oxygen combined. What loss of mass
Answer: see below
Explanation:
Mg burning in air gives MgO and a smaller amount of Mg3N2
2Mg+O2=2MgO. 2*24.3+32=2*40.3
3Mg+N2=Mg3N2
Ignoring the nitride, MgO loss of mass during the reaction can be ascribed to
(1) relativistic loss as energy (too small to be measurable)
(2) During the reaction, which is strongly exothermic, a fraction f the material is blown off as tiny particles which adhere to the vessel.
In order to inexpensively determine the contamination level of a sample of water, a new test is known to yield almost exactly the same value when repeatedly used on samples from the same container of water. However, these individual values are not close to the true average contamination level for the large container. The concern with using this new, cheaper test to determine the contamination level for a single sample of water is that this measurement method is not
Answer:
The correct answer is - valid.
Explanation:
In this case, there is consistency in the results measures in the experiment which makes this method reliable. The consistency of a measure is referred to the reliability.
It is also given that the level of contamination of individual containers as per the average parameter of the contamination of large containers which makes this method not valid as the measurement method is how correctly it measures the true value of the parameter.
Thus, the correct answer is - method is reliable, but not valid.
Why do we see this star pattern in the winter, but not at other times of the year? (2 points)
Answer: We see constellations at different times of the year - spring, summer, fall, & winter. This occurs because the Earth is orbiting the Sun.
Explanation:
How many moles are in 3.01 x 10^23 atoms of zinc?
Answer:
What is ^ for?
Explanation:
How many carbon atoms are represented by Mg(HCO3)
A solution is prepared by dissolving 10.6 g sodium carbonate in enough water to produce
500.0 mL solution. What is the molarity of sodium carbonate in the solution?
Answer:
0.2mol/dm³
Explanation:
Given parameters:
Mass of Na₂CO₃ = 10.6g
Volume of solution = 500mL
Unknown:
Molarity of solution = ?
Solution:
The molarity of a solution can be determined using the expression below:
Molarity = [tex]\frac{number of moles }{volume}[/tex]
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of Na₂CO₃ = 2(23) + 12 + 3(16) = 106g/mol
Number of moles = [tex]\frac{10.6}{106}[/tex] = 0.1mol
Convert mL to dm³;
500mL will give 500 x 10⁻³dm³or 0.5dm³
So;
Molarity = [tex]\frac{0.1}{0.5}[/tex] = 0.2mol/dm³
what is the chemical symbol for fluoride
Answer:
I think F
Explanation:
Define the following Vocabulary words
1. Archae Bacteria
2. Bacteria
3. Eukarya Kingdom
4. Domain
WORTH 35 POINTS! MY LIFE DEPENDS ON IT HELP!
When naming ionic compounds, always
1. use prefixes
2. write the metal first
3. write the nonmetal first
4. capitalize the metal and nonmetal
Answer
2.Write the metal first ( if I am right) as it is ionised
What is the answer for number 9 in the Half-life gizmo activity B.
Earths outer core is made of ___
Answer:
iron and nickel (liquid metal )
Explanation:
The outer core is the third layer of the Earth. It is the only liquid layer, and is mainly made up of the metals iron and nickel, as well as small amounts of other substances. The outer core is responsible for Earth’s magnetic field. As Earth spins on its axis, the iron inside the liquid outer core moves around
Answer:
The outer core is the third layer of the Earth. It is the only liquid layer, and is mainly made up of the metals iron and nickel, as well as small amounts of other substances.
Explanation:
The diagram shows the electron configuration around the chlorine nucleus. Chlorine has 17 protons.
CI
Which of the following correctly completes the statement?
Chlorine has valence electrons, and the effective nuclear charge, Zett, for the chlorine atom shown is
O A. 7,7+
OB. 7,7-
O C. 10,7-
D. 17, 7+
Answer: A. [tex]7,+7[/tex]
Explanation:
Valence electrons are the number of electrons constituting the outermost shell of an atom. It is also defined as the electrons that take part in the formation of a chemical bond.
The atomic number of chlorine is 17 as it has 17 protons and the electronic configuration will be 2,8,7. Thus the electrons present in the outermost shell are 7 and hence the valence electrons are 7.
Effective nuclear charge is the net positive charge experienced by valence electrons. It is calculated by: Zeff = Z – S
where Z = atomic number , S = number of shielding electrons.
Thus for Chlorine , [tex]Z_{eff}=17-10=7[/tex]
One mole of a metallic oxide reacts with one mole of hydrogen to produce two moles of the pure metal
and one mole of water. 5.00 g of the metallic oxide produces 2.32 g of the metal. What is the metallic
oxide?
Answer:
Lithium oxide, Li₂O.
Explanation:
Hello!
In this case, according to the given amounts, it is possible to write down the chemical reaction as shown below:
[tex]M_2O+H_2 \rightarrow 2M+H_2O[/tex]
Which means that the metallic oxide has the following formula: M₂O. Next, we can set up the following proportional factors according to the chemical reaction:
[tex]5.00gM_2O*\frac{1molM_2O}{(2x+16)gM_2O}*\frac{2molM}{1molM_2O}*\frac{xgM}{1molM} = 2.32gM[/tex]
Thus, we perform the operations in order to obtain:
[tex]\frac{10x}{2x+16}=2.32[/tex]
So we solve for x as shown below:
[tex]10x = 2.32(2x+16)\\\\10x = 4.64x+37.12\\\\x = \frac{37.12}{10-4.64}\\\\x= 6.93 g/mol[/tex]
Whose molar mass corresponds to lithium, and therefore, the metallic oxide is lithium oxide, Li₂O.
Best regards!
g A and B are both non-volatile molecular compounds. Substance A has a greater molar mass than substance B. If 50 g of substance A are dissolved in 250 g of water in one beaker, and 50 g of substance B are dissolved in 250 g of water in another beaker, then which ONE statement below will be true? A) the vapor pressure of solution A will be lower than the vapor pressure of solution B. B) the solution of A will freeze at a lower temperature than the solution of B. C) the two solutions will have the same vapor pressure. D) the boiling point of solution A will be lower than the boiling point of solution B. E) the solution of A will have a higher osmotic pressure than the solution of B.
Answer:
The correct answer is - option D. the boiling point of solution A will be lower than the boiling point of solution B
Explanation:
Colligative properties such as a decrease in the freezing point of the solution, increase in the boiling point of substance, decrease in Lowering of vapor pressure, and other properties depend upon the number of molecules only.
In the given solution the equal amount of two solutions are mixed that is 50 grams however due to the difference in the molecular mass so the atoms present in both solution A and B will be different. It is known that the number of atoms of a substance is inversely proportional to the molecular mass of the particular substance.
As it is given that Solution B has a low molecular mass which means it has a high number of atoms that means its boiling point will be higher than solution A.
In a heterogeneous chemical reaction requiring the use of a solid catalyst, the rate of the reaction could not be increased by increasing the concentration of reactants, but was doubled by doubling the amount of solid catalyst added. This probably indicated that
Answer:
The active sites on the initial amount of catalyst were fully saturated
Explanation:
A catalyst is a substance which alters the rate of a chemical reaction but largely remains unaltered at the end of the reaction. A catalyst has an active site which enables it to catalyze a reaction.
The active site provides the best possible orientation for reactant molecules to collide in order to form products.
When the active sites are not fully saturated with reactant molecules, more reactant molecules can bind and the reaction can proceed much faster. However, if the active sites of the catalysts are fully saturated, the reaction has maximum velocity and cannot go anymore faster.
Addition of more catalyst molecules can however make the reaction proceed faster as a it provides more active sites for reaction for the reactants.
True or false questions?
Most metal elements are brittle and do not conduct electricity. True or False
Any element can be identified by counting the protons in its neucleus. True or False
All Earths matter is made from the combination of about 100 elements. True or false
Answer:
1. False 2.True3.True? Unsure
Explanation:
How many moles are equal to 4.11x10^23 molecules of carbon dioxide?
Answer: 0.68 mole
Explanation:
1 mole (of any atom/molecule) = 6.02214076*10^23
0.683 moles are equal to 4.11x10²³ molecules of carbon dioxide.
What do you mean by the term mole?A mole is a unit of measurement in the International System of Units (SI) used to express an amount of a substance.
One mole is defined as the amount of a substance that contains as many elementary entities as there are atoms in 12 grams of pure carbon-12.
This number is known as Avogadro's number and is approximately 6.023 x 10²³.
Given:
For the number of moles of carbon dioxide in 4.11x10^23 molecules Avogadro's number = 6.023x10²³ particles per mole.
Therefore, the number of moles of carbon dioxide can be calculated as:
moles = number of particles / Avogadro's number
moles = 4.11x10²³ / 6.022x10²³
moles = 0.683 moles
Thus, 4.11x10²³ molecules of carbon dioxide are equal to 0.683 moles of carbon dioxide.
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How many mols of NaOH are there in 10 grams of NaOH? *
Answer:
0.25 moles
Explanation:
The molar mass of NaOH is 40 g/mol.
[tex]\frac{10g}{40g/mol}[/tex] This equals 0.25 moles
How many moles of aluminum will be produced from 30.0 g of Al2O3 in the following reaction?
2A1203 - 4A + 302
Moles of aluminum produced = 0.588
Further explanationGiven
30 g of Al2O3
Reaction
2Al203 ⇒ 4Al + 302
Required
moles of aluminum
Solution
mol Al2O3 :
= mass : MW
= 30 : 101,96 g/mol
= 0.294
From the equation, mol Aluminum :
= 4/2 x mol Al2O3
= 4/2 x 0.294
= 0.588
what are the three important properties of acids
What are the different elements that make up a molecule of glucose?
Answer:
Glucose has a chemical formula of: C6H12O6 That means glucose is made of 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms. You will be building one type of sugar called glucose.
Explanation:
what Li(s) + O2(g) -> Li2O(s) balanced is
Answer:
4 1 2Explanation:
4 Li(s) + 1 O2(g) -> 2 Li2O(s)
To calculate the atoms of an element in a given molecule, we need to multiply stoichiometry by the number that is written on the foot of that element. Therefore, the balanced equation is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s).
What is Balanced equation?Balanced equation is the one in which the total number of atoms of a species on reactant side is equal to the total number of atoms on product side. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, displacement reaction.
The other characteristic of balanced reaction is that physical state should be written with each compound or molecule on reactant and product side. Physical state should be written in brackets. s means solid, l means liquid, g means gas. The balanced equation for the given reaction is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s)
Therefore, the balanced equation is 4 Li(s) + 1 O[tex]_2[/tex](g) [tex]\rightarrow[/tex] 2 Li[tex]_2[/tex]O(s).
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which statement is true about both groundwater and surface water?
A. Rainwater forms both the groundwater and the surface water
B. The water levels of both the groundwater and the surface water stay stable
C. Both the groundwater and the surface water are purified as they soak through the soil layers
D. The groundwater and the surface water together form a drainage basin
The statement which is true about both groundwater and surface water is that the groundwater and the surface water together form a drainage basin.
What is ground water?
Ground water is the type of water which is present below the surface of rock and between spaces in soil pores .Thirty percent of the available fresh water is present in the form of groundwater.
Groundwater is discharged from the surface naturally in the form of springs and seeps and can also exist in the form of oases or wetlands.It is used for various purposes like for agriculture, municipal and industrial uses. They are used by constructing wells .
The study of movement and distribution of ground water is called hydrogeology or even groundwater hydrology.It is a cheaper source of water and is less prone to pollution as compared to surface water.
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a golf ball is hit at a distance of 300 yards in 10 seconds what is the speed of the golf ball
Answer:
30 yard per second
Explanation:
300/10 = 30
You find yourself in a room with dark gray walls. Medeleev’s image says, “This element is essential for plant life to thrive and is found in heavy clay minerals and the ash from your campfire.” What element are these walls made from?
Answer:
juvn hgf jb ujvi i junk food sux
Explanation:
What does CoH12O6 tell you about the glucose molecule?
Answer:
Glucose = C6H12O6
molecular mass = 6(12) + 12(1) + 6(16)
= 72 + 12 + 96
= 180 g
Explanation:
Glucose has a chemical formula of: C6H12O6 That means glucose is made of 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms. ... Glucose is produced during photosynthesis and acts as the fuel for many organisms.
The following chemical reaction occurs.
2H2O2
2H20 + O2
How many atoms of hydrogen are involved in the reaction?
Answer: B. 4
Explanation:
Pure acetic acid is often called glacial acetic acid because it is purified by fractional freezing at its melting point of 16.6 °C. At 1 atm, a flask containing several moles of acetic acid at 16.6 °C is briefly lowered into an infinitely large ice-water bath. When it is removed it is found that exactly 1 mol of acetic acid has frozen. Given: ΔH_fusion,acetic acid = 11.45kJ/mol and ΔH_fusion, H2O= 6.01 kJ/mol.
Required:
a. What is the change in entropy of the acetic acid?
b. What is the change in entropy of the water bath?
c. Now consider that the water bath and acetic acid are the same system. What is the entropy change for the combined system? Is the process reversible or irreversible? Why?
Answer:
Explanation:
a ) ΔH_fusion of acetic acid is 11.45 kJ / mol . It means 11.45 kJ of heat will be released when 1 mole of acetic acid will freeze . During this process temperature of acetic acid will be constant .
Temperature of acetic acid T = 16.6⁰C = 273 + 16.6 K = 289.6 K .
By definition change in entropy
ΔS = dQ / T
= dH / T
As temperature remains constant during withdrawal of heat
ΔS = ΔH / T
T = 289.6 K .
ΔH = - 11.45kJ
ΔS = - 11.45kJ / 289.6
= - 11450 / 289.6
= - 39.53 J
It will be negative as heat is released by acetic acid .
b )
Heat amounting ΔH will be absorbed by water bath so its entropy will be increased . As water bath is very large , temperature of bath also will remain constant at 289.6 K .
Increase in entropy of water bath =
ΔS = ΔH / T
T = 289.6 K .
ΔH = 11.45kJ
ΔS = 11.45kJ / 289.6
= 11450 / 289.6
= 39.53 J
c )
consider that the water bath and acetic acid are the same system : --
Total change in the heat content of the system
= 289.6 - 289.6 = 0
So for the whole system
ΔQ =ΔH = 0
Change in entropy is zero .
Δ G = ΔH - TΔS
= ΔH - ΔH = 0
ΔG = 0
Change in entropy is zero .
pertain to the following class, Point:
public class Point {
private double x;
private double y;
public Point() {
this (0, 0);
}
public Point(double a, double b) {
/* missing code */
}
// ... other methods not shown
}
Which of the following correctly implements the equals method?
public boolean equals(Point p) {
return (x == p.x && y == p.y );
}
public void equals(Point p) {
System.out.println(x == p.x && y == p.y);
}
public void equals(Point p) {
return (x == p.x && y == p.y );
}
public boolean equals(Point p) {
return (x == Point.x && y == Point.y);
}
public boolean equals(Point p) {
System.out.println(x == p.x && y == p.y);
}
_______________________
The default constructor sets x and y to (0, 0) by calling the second constructor. What could be used to replace /* missing code */ so that this works as intended?
a = 0;
b = 0;
this (x, y);
this(0, 0);
x = a;
y = b;
a = x;
b = y;
_____________________
Which of the following correctly implements a mutator method for Point?
public double getX() {
return x;
}
public void setCoordinates (double a, double b) {
x = a;
y = b;
}
None of the items listed.
public double getX() {
return a;
}
public void setCoordinates (double a, double b) {
Point p = new Point(a,b);
}
b = 0;
this (x, y);
this(0, 0);
x = a;
y = b;
a =x
This above solution is just according to the public boolean equals(Point p) { return (x == p.x && y == p.y ); and public void equals(Point p) { System.out.println(x == p.x && y == p.y);}
What is public void?An abstract class contains a pure virtual function. Pure virtual class cannot be instantiated but it can be subclassed and the subclass can provide an implementation of the function.
A virtual function declaration in the class is preceded by the virtual keyword. For example, virtual void print();
A pure virtual function declaration is followed by '=0;'
public: virtual void print()=0;
The main method header is written as public static void main(String[] args). A main method is something that is required in Java. You must have at least one class with a method named main. In Java, main is a static method, which means that it is part of its class but not parts of objects.
Therefore, This above solution is just according to the public boolean equals(Point p) { return (x == p.x && y == p.y ); and public void equals(Point p) { System.out.println(x == p.x && y == p.y);}
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Compare the two shampoo
Answer:
Explanation:
I think you forgot to attach an image here!
