Answer:
e. The reaction is spontaneous at low temperatures.
Explanation:
The reaction 2Mg(s) + O2(g) → 2MgO(s) is an exothermic reaction. Let us recall that in an exothermic reaction, heat and light are given out and ΔH is negative (less than zero).
In an exothermic reaction increase in temperature shifts the equilibrium position towards the left and more reactants are produced. However, decrease in temperature shifts the equilibrium position towards the right and more products are obtained.
Also, since the reaction is exothermic, then given that; ΔG = ΔH - TΔS, ΔH is negative for an exothermic reaction and ΔG must be negative for a reaction to be spontaneous. Hence, at low temperature, the value of ΔH - TΔS remains negative (less than zero) hence the reaction is spontaneous.
Hence, Being an exothermic reaction, the process is spontaneous at low temperatures.
in this trial, 0.400 M NaOH was added to 40.00 ml of 0.400 M HCl. How many ml of base must be added to cause the colour to change?
Answer:
The amount of Ml that is needed
A cube of an unknown metal measures 0.200 cm on one side. The mass of the cube is 52 mg. Which of the following is most likely the unknown metal?
Metal Density(g/cm^3)
rhodium 12.4
copper 8.96
niobium 8.57
vanadium 6.11
zirconium 6.51
a. copper
b. rhodium
c. niobium
d. vanadium
e. zirconium
Answer:
Option E. Zirconium
Explanation:
From the question given above, the following data were obtained:
Length of side (L) of cube = 0.2 cm
Mass (m) of cube = 52 mg
Name of the unknown metal =?
Next, we shall determine the volume of the cube. This can be obtained as follow:
Length of side (L) of cube = 0.2 cm
Volume (V) of the cube =?
V = L³
V = 0.2³
V = 0.008 cm³
Next, we shall convert 52 mg to g. This can be obtained as follow:
1000 mg = 1 g
Therefore,
52 mg = 52 mg × 1 g / 1000 mg
52 mg = 0.052 g
Thus, 52 mg is equivalent to 0.052 g.
Next, we shall determine the density of the unknown metal. This can be obtained as follow:
Mass = 0.052 g.
Volume = 0.008 cm³
Density =?
Density = mass / volume
Density = 0.052 / 0.008
Density of the unknown metal = 6.5 g/cm³
Comparing the density of the unknown metal i.e 6.5 g/cm³ with those given in table in the above, we can conclude that the unknown metal is zirconium
Select the atom/ion in each pair which has a larger radius F or F-1
Answer:
F-
Explanation:
The atomic radius of F is 72 pm and that of F- is 136 pm.
Three type of symbiosis
Answer:
mutualism, commensalism, and parasitism.
Question:
Three type of symbiosis
Answer:
Mutualism: both partners benefit. ...
Commensalism: only one species benefits while the other is neither helped nor harmed. ...
Parasitism: One organism (the parasite) gains, while the other (the host) suffers
Little Info.
Symbiosis is a close relationship between two species in which at least one species benefits. For the other species, the relationship may be positive, negative, or neutral. There are three basic types of symbiosis: mutualism, commensalism, and parasitism
Whats a homogeneous mixture? A mixture that contains particles_____________
A. that are unevenly mixed together
B. that are evenly mixed together
C. that eventually separate
D. suspended in gelatin
Answer:
A homogeneous mixture is a mixture in which the components that make up the mixture are uniformly distributed throughout the mixture.
Explanation:
Suppose you wish to use this reaction to determine the weight percentage of TiO2 in a sample of ore. To do this you collect the O2 gas from the reaction. If you find that 1.586 grams of the TiO2 containing ore evolved 32.1 mg of oxygen gas, what is the weight percent of TiO2 and Ti in the ore
Answer:
Mass percentage of TiO2 in the ore = 5.04%
Mass percentage of Ti = 3.01%
Explanation:
Equation of reaction is given below:
3 TiO2(s) + 4 BrF3(l) ---> 3 TiF4(s) + 2 Br2(l) + 3 O2(g)
From the equation of reaction above, 3 moles of O2(g) is obtained from 3 moles of TiO2(s)
Molar mass of O2 = 32 g/mol; molar mass of TiO2 = 79.87 g/mol, molar mass of Ti = 47.87 g/mol
Number of moles of O2 in 32.1 mg or 0.0321 g of O2 = 0.0321 g/32 g/mol = 0.001 moles
Therefore, 0.001 moles of O2 will be obtained from 0.001 moles of TiO2
Hence, mass l of 0.001 moles of TiO2 = 0.001 moles x 79.87g/mol = 0.07987
Mass percentage of TiO2 in the ore = 0.07987 x 100/1.586 = 5.04%
Mass of Ti in sample = (0.07987 - 0.03210) g = 0.04777 g
Mass percentage of Ti = 0.04777 × 100/1.586 = 3.01%
NH4I(s) NH3(g) HI(g) Calculate the equilibrium concentration of HI when 0.343 moles of NH4I(s) are introduced into a 1.00 L vessel at 673 K. [HI]
This question is incomplete, the complete question is;
The equilibrium constant, Kc, for the following reaction is 7.00×10-5 at 673 K. NH4I(s) ---> NH3(g) + HI(g) Calculate the equilibrium concentration of HI when 0.343 moles of NH4I(s) are introduced into a 1.00 L vessel at 673 K
Answer:
the equilibrium concentration of HI is 1.302 × 10⁻⁵ M
Explanation:
Given that;
kc = 7.00 × 10⁻⁵ at 673 K
equilibrium concentration of HI = ?
when 0.343 moles of NH4I(s) are introduced into a 1.00 L vessel at 673 K
Molarity of NH4I = 0.343 / 1.00 = 0.343 M
NH4I(s) -----------------> NH3(g) + HI(g)
0.343 0 0 ------> Initial
(0.343 - x) x x -------> equilibrium
we know that; solid does not take part in equilibrium constant expression
so
KC = [NH3] [HI] / NH4I
we substitute
7.00 × 10⁻⁵ = x² / (0.343 - x)
0.00007 (0.343 - x) = x²
0.00002401 - 0.00007x = x²
x² + 0.00007x - 0.00002401 = 0
using; x = -b±√(b² - 4ac) / 2a
we substitute
x = -0.00007 ± √((0.00007)² - 4×1×-0.00002401) / 2×1
x = [-0.00007 ± √( 4.9×10⁻⁹ + 9.604×10⁻⁵)] / 2
x = [-0.00007 ± 0.00009604] / 2
Acceptable value of x = [-0.00007 + 0.00009604] / 2
x = 0.00002604 /2
x = 0.00001302 ≈ 1.302 × 10⁻⁵ M
therefore the equilibrium concentration of HI is 1.302 × 10⁻⁵ M
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Pure metals possess few important physical and metallic properties, such as melting point, boiling point, density, specific gravity, high malleability, ductility, and heat and electrical conductivity. These properties can be modified and enhanced by alloying it with some other metal or nonmetal, according to the need.
Alloys are made to:
Enhance the hardness of a metal: An alloy is harder than its components. Pure metals are generally soft. The hardness of a metal can be enhanced by alloying it with another metal or nonmetal.
Lower the melting point: Pure metals have a high melting point. The melting point lowers when pure metals are alloyed with other metals or nonmetals. This makes the metals easily fusible. This property is utilized to make useful alloys called solders.
Enhance tensile strength: Alloy formation increases the tensile strength of the parent metal.
Enhance corrosion resistance: Alloys are more resistant to corrosion than pure metals. Metals in pure form are chemically reactive and can be easily corroded by the surrounding atmospheric gases and moisture. Alloying a metal increases the inertness of the metal, which, in turn, increases corrosion resistance.
Modify color: The color of pure metal can be modified by alloying it with other metals or nonmetals containing suitable color pigments.
Provide better castability: One of the most essential requirements of getting good castings is the expansion of the metal on solidification. Pure molten metals undergo contraction on solidification. Metals need to be alloyed to obtain good castings because alloys
Which of the following BEST describes a way in which water moves in the water cycle?
A. Water falls from the sky as rain. It stays where it falls until it evaporates
B. Water falls from the sky as snow. As the snow melts, the water runs up to Earth's mountains.
C. Water falls from the sky as rain. The water then flows downhill
D. Water falls from the sky as hail. The hail is eventually buried in the ground
Answer:
C. Water falls from the sky as rain. The water then flows downhill.
Explanation:
Water cycle can be defined as a process which typically involves the circulation (movement) of water between the Earth's atmosphere, land and ocean under various atmospheric conditions such as precipitation (rain and snow), transpiration, condensation and evaporation.
Basically, the movement of the water starts from the sky due to the condensation of water vapor to form clouds and later result to rainfall. Consequently, the rain water are either soaked by the soil or are made to flow down the hill.
The statement which best describes a way in which water moves in the water cycle is that, water falls from the sky as rain. The water then flows downhill or seeps into the ground.
How many hydrogen atoms are present in .46 moles of NH3
Answer:
2.78 x 10²³
Explanation:
1 mole contains 6.02 x 10²³ hydrogen atoms => 0.46 mole contains 0.46(6.02 x 10²³) hydrogen atoms or 2.78 x 10²³ atoms.
Caution => When to use H vs H₂ => This problem is specific for 'hydrogen atoms' but some may simply say hydrogen. In such cases use H₂ or 'molecular hydrogen' is the focus. it's a matter of semantics, H vs H₂.
What is the molarity of a 3.0 solution of magnesium chloride prepared with 9.0 molecules of MgCl2 A. 6.0 M B. 3.0 M C. 27.0 M D. 0.33 M PLEASE HELP IM GOING TO CRY SO MUCH IF I FAIL
Answer:
Option B. 3.0 M
Explanation:
From the question given above, the following data were obtained:
Volume of solution = 3.0 L
Mole of MgCl₂ = 9 moles
Molarity =?
Molarity can simply be defined as the mole of solute per unit litre of the solution. Mathematically, it can be expressed as:
Molarity = mole of solute /Volume of solution
With the above formula, we can obtain the molarity of the solution as follow:
Volume of solution = 3.0 L
Mole of MgCl₂ = 9 moles
Molarity =?
Molarity = mole of solute /Volume of solution
Molarity = 9 / 3
Molarity = 3 mol/L = 3.0 M
Thus, the molarity of the solution is 3 M
Which of the following energy resources provides non-recyclable energy and is also the least polluting?
a) Biomass energy
b) Nuclear power
c) Hydropower
d) Natural gas
Answer:
b) Nuclear power
Explanation:
The nuclear power plant generated the nuclear energy that utilize the radio active materials like uranium i.e. finite. Thus, this is a non-recyclable.
Also this energy does not release any type of polluting gas neither it is harmful like carbon dioxide or any green house gases So it would be least polluting
Therefore as per the given statement, the option b is the correct one
Answer:
b) Nuclear power
Explanation:
took the test :)
Which of the following metal ions can potentially form both low-spin and high-spin complexes?
a. Ti2+
b. Cu+
c. Fe2+
d. Ni2+
e. Cr3+
Answer:
c. Fe2+
Explanation:
Coordination compounds comprise solely complex ions together with one or more counter ions. They are compounds in which metal atoms or ions are directly bonded to anions or neutral atoms in conjunction with coordinate covalent bonds.
From the given options, only Fe2+ can form both low-spin and high-spin.
To determine that, we find out the number of unpaired spins in Fe2+
At the ground state:
The electronic configuration is:
Fe: [Ar] 3d⁶ 4s²
After the removal of two electrons, the configuration becomes
Fe²⁺ : [Ar] 3d⁶
A metal ion has the ability to form both low-spin and high-spin complexes if the metal-ion comprises more than 3 and less than 8 d -electrons.
So, since Fe²⁺ contains more than 3 and less than 8. Then Fe²⁺ is the right option.
Ti²⁺ contains only two d electrons
Cu⁺ contains more than eight d electrons
Ni²⁺ contains eight d electrons
Cr³⁺ contains three d electrons
Of the choices below, which is the most abundant gas in Earth's atmosphere?
Practice
A
argon
B
nitrogen
C
carbon dioxide
D
oxygen
Answer:
B. Nitrogen
Explanation:
Hope this helps :)
The answer is nitrogen gas.
A compound has a molecular weight of 146 g/mol. A 0.3250 g sample of the compound contains 0.1605 g of carbon, 0.0220 g of hydrogen, and 0.1425 g of sulfur. What is the molecular formula of the compound
Answer: The molecular formula is [tex]C_6H_{10}S_2[/tex]
Explanation:
We are given:
Mass of [tex]C[/tex] = 0.1605 g
Mass of [tex]H[/tex]= 0.0220 g
mass of [tex]S[/tex] = 0.1425 g
Step 1 : convert given masses into moles.
Moles of C =[tex]\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{0.1605g}{12g/mole}=0.0134moles[/tex]
Moles of H =[tex]\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{0.0220g}{1g/mole}=0.0220moles[/tex]
Moles of S =[tex]\frac{\text{ given mass of S}}{\text{ molar mass of S}}= \frac{0.1425g}{32g/mole}=0.0044moles[/tex]
Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.
For C = [tex]\frac{0.0134}{0.0044}=3[/tex]
For H = [tex]\frac{0.0220}{0.0044}=5[/tex]
For S =[tex]\frac{0.0044}{0.0044}=1[/tex]
The ratio of C : H: S= 3: 5: 1
Hence the empirical formula is [tex]C_3H_5S[/tex]
The empirical weight of [tex]C_3H_5S[/tex] = 3(12)+5(1)+1(32)= 73g.
The molecular weight = 146 g/mole
Now we have to calculate the molecular formula.
[tex]n=\frac{\text{Molecular weight }}{\text{Equivalent weight}}=\frac{146}{73}=2[/tex]
The molecular formula will be=[tex]2\times C_3H_5S=C_6H_{10}S_2[/tex]
If you are heating something, you can step away for a moment, as long as you come back very quickly.
a. True
b. False
Answer: b. False
Explanation:
The more energetic molecules move to a gas, spread out, and form bubbles when heating happens. When exposed to heat, many of the chemicals used in the laboratory are volatile and harmful (fire).
So leaving a material that you heat for even a second can be very hazardous and negligent.
How many moles of magneslum chloride are there in 148 grams of magnesium chloride?
Answer:
1.554442238816872 moles
Explanation:
Answer:
1.5544422388169434
Explanation:
1 mole is equal to 1 moles Magnesium Chloride, or 95.211 grams.
Vote me the brainliest
Classify this reaction.
C3H6(g) + O2(g) → CO2(g) + H2O(g)
a
Single Replacement
b
Synthesis
c
Double Replacement
d
Combustion
Answer:
d
Combustion
Explanation:
24. H2SO4 has
a) ionic bond
b) both Ionic and covalent bonds
c) ionic, covalent and coordinate bonds
d) covalent bond
Answer:
C.
Explanation:
para sakin letter C ganonn
When a galvanic cell is comprised of an anode and a cathode of precisely the same material, this is called a(n):
Answer:
Concentration cell
Explanation:
Galvanic cells and even electrolytic cells usually consist of two electrodes namely anode and cathode. These 2 electrodes can either be made of the same metals or different metals, and also an electrolyte whereby the two electrodes are immersed.
Now, in the case where the electrodes are made of the same metal, we call it a concentration cell because A concentration cell is a cell that consists of two half-cells that have the same electrodes, but yet differ in concentrations.
In a bowl of 50 skittles, you have 12 yellow, 9 orange, 11 red, and 13 green. The rest of the skittles are purple. What percentage of the skittles are red? What percentage of the skittles are not green?
Answer:
percentage of red skittles = 22%
percentage of skittles that are not green = 74%
Explanation:
total skittles = 50
yellow = 12
orange = 9
red = 11
green = 13
purple = 50-12-9-11-13
= 5
1) percentage of red skittles
[tex] \frac{red \: skittles}{total \: skittles} \times 100[/tex]
[tex] \frac{11}{50} \times 100[/tex]
[tex] \frac{22}{10} [/tex]
[tex]22\%[/tex]
2) percentage of skittles that are not green
[tex] \frac{total \: skittles - green \: skittles}{total \: skittles} \times 100[/tex]
[tex] \frac{50 -13 }{50} \times 100[/tex]
[tex] \frac{37}{50} \times 100[/tex]
[tex]74\%[/tex]
What was a result of the Zhou capital being destroyed by invaders?
A) Leaders of the feudal states declared independence.
B) Loyal relatives supported the king to protect the empire.
C) Feudal rulers began to use nomadic soldiers in their armies.
D) Philosophers gained power by encouraging citizens to rebel.
Answer:
A
Explanation:
Answer:
think it is D
Explanation:
hope this helps
if you start with 362 grams of C3 H8 how many grams of H2O will be produced
Answer:
52 g H2O (to 2 significant figures)
Explanation:
I hope you like my answer:)
Can you mark me as brainliest please
What is the percent of hydrogen by mass in HNO3?
the percent of hydrogen by mass in HNO3 is 1.600%
Answer:
[tex]\boxed {\boxed {\sf 1.5996953 \%\ or \ 1.6 \%}}[/tex]
Explanation:
Percent composition tells us the mass percentage of an element in a compound. It can be found by dividing the mass of the element by the mass of the compound, then multiplying by 100.
[tex]\frac{element \ mass}{compound \ mass} *100[/tex]
1. Compound Mass
The compound given is HNO₃
Hydrogen (H) and Nitrogen (N) have no subscript, implying there is 1 atom of each element. Oxygen (O) has a subscript of 3, so there are 3 atoms.Use the Periodic Table to find the masses of each element.
Hydrogen: 1.008 u Nitrogen: 14.007 u Oxygen: 15.999 uNext, multiply each element's mass by the number of atoms, then add them together.
(1.008 u) + (14.007 u) + (3 * 15.999 u)63.012 u2. Percent Composition
Now we know that HNO₃'s mass is 63.012 u. This is the compound mass.
We want to find the percent of hydrogen and its mass is 1.008 u. This is the element mass.
[tex]\frac{1.008 \ u }{63.012\ u } *100[/tex]
[tex]0.015996953*100[/tex]
[tex]1.5996953[/tex]
This can be rounded to the nearest tenth. The 9 in the hundredth place tells us to round the 5 to a 6.
[tex]\approx 1.6[/tex]
The percent of hydrogen in HNO₃ is 1.5996953% or about 1.6%
If the decomposition of a sample of KClO3 produces 3.29 g of O2. What was the mass (g) of the original sample?
Answer: 8.41 g
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} O_2=\frac{3.29g}{32g/mol}=0.103moles[/tex]
The balanced chemical equation for decomposition is :
[tex]2KClO_3\rightarrow 2KCl+3O_2[/tex]
According to stoichiometry :
As 3 moles of [tex]O_2[/tex] are produced by = 2 moles of [tex]KClO_3[/tex]
Thus 0.103 moles of [tex]O_2[/tex] are produced by =[tex]\frac{2}{3}\times 0.103=0.0687moles[/tex] of [tex]KClO_3[/tex]
Mass of [tex]KClO_3=moles\times {\text {Molar mass}}=0.0687moles\times 122.5g/mol=8.41g[/tex]
8.41 g was the mass of the original sample.
In the NCl3 molecules there are banded pairs of electrons and nonbonded pairs of electrons attached to central atom?
Answer: the anwser is a. cuz i did it so im smart and u should listen to me
Explanation:non>
A change in pH usually produces a change in enzyme activity because:_______.Select one:a. pH of the environment changes the conformation of the enzyme.b. enzyme activity increases at extreme pH values (either acidic or basic).c. enzyme activity is usually least active below its optimum pH.d. enzyme activity is most active above its optimum temperature.
Answer:
c. enzyme activity is usually least active below its optimum pH
Explanation:
Enzyme activity depends highly on pH. Enzymes are biological molecules which are proteins and influence the rates of important biochemical reactions in the human body.
Enzymes has a value of pH at which it works most perfectly. This pH value is known as its optimum pH. Above or below this value, the enzyme does not function optimally.
Hence, a change in pH usually produces a change in enzyme activity because enzyme activity is usually least active below its optimum pH
Which method would be best to separate a mixture of sugar and water?
1.separation by density
2.separation by particle size
3.fration
4.distillation
Answer:
distillation
Explanation:
distillation is better suited separation method
How to convert chlorophenylamine to bromochlorobenzene
Answer:
hey buddy,This's your answer...!!
The hybrid orbital set used by the central atom in IO2- is ________.
Explanation:
[tex]IO_2^-[/tex] is the Iodite ion. The ion has a total of 7+6(2)+1 = 20 electrons. The Iodite ion, or iodine dioxide anion, is the halite with the chemical formula IO−
2. Within the ion the Iodine exists in the oxidation state of +3. The hybridization state of central atom I in Iodite ion is [tex]d^2sp^3[/tex].