Answer:
A) positive; added
Explanation:
Based on the reaction:
2NaHCO3(s) + 129kJ → Na2CO3(s) + H2(g) + CO2(g)
2 moles of NaHCO3 requires 129kJ to produce 1 mole of Na2CO3, 1 mole of H2 and 1 mole of CO2.
That means, the energy must be added being, thus, an exothermic reaction. The exothermic reactions have ΔH >0.
Thus, right answer is:
A) positive; added
Calculate the mass of NaOH
required to prepare a 0.343M
solution dissolved in 2500mL
of water.
Answer:
will this work or help?
Explanation:
Calculate the mass of NaOH required to prepare a 0.343 M solution dissolved in 2500 mL of water. 0.343 M = x mol / 2.5 L = 0.86 mol 0.86.
18. How many grams are in 563 mL of chlorine gas at STP?
Answer:
[tex]at \: stp : \\ 22400 \: ml \: are \: occupied \: by \: 71 \: g \: of \: chlorine \\ 563 \: ml \: will \: be \: occupied \: by \: ( \frac{563}{22400} \times 71) \:g \\ = 1.78 \: g[/tex]
What is the pH of 1.0 M KOH solution?
Answer:
pH = 14
Explanation:
pOH = -log[OH-] = -log1,0 = 0
pH + pOH = 14
pH = 14 - pOH = 14 - 0 = 14
Answer:
pH= 14Explanation:
hope it helps
#CARRYONLEARNINGHow is coal extracted?
How do Humans use it?
What are the benefits?
Coal is extracted by mining.
Once coal has been extracted, it can be used directly for heating and industrial processes or to fuel power plants for electricity.
Benefits are:
Coal energy is an affordable energy source because of the coal's stable price compared to other fuel sources.
Coal is easy to burn.
Coal produces high energy upon combustion.
Coal energy is inexpensive.
6.
An element with high conductivity would be found in which
category?
Alkaline earth metals
transition metals
Group 1 metal
Alkali metals
***Why would you not pick the others?
A sample of river wayer contains 125mg per dm^3 of dissolved soilds. Calculate the mass of dissolved soilds in grams in 250 cm^3 of this sample of river water. Giver your answer to 2 significant figures (4 marks)
I will give brainilist to anyone who answers
The mass of a substance is the product of its density and volume. Thus, the mass of the dissolved solids with a density of 125 mg/dm³ with a volume of 250 cm³ is 31.25 mg.
What is density?Density of a substance is the measure of its mass per unit volume. Thus it describes how much denser the substance is in a given volume. Mathematically it is the ratio of mass to the volume.
Density of a substance depends on the mass, volume, bond type, temperature and pressure. The ratio of density of a substance with the density of water is called its specific gravity.
It is given that the density of the dissolved solids is 125 mg/dm³ and the volume is 250 cm³ or 0.25 dm³. Thus the mass can be calculated as follows:
density = mass/volume
mass = density × volume
= 0.25 dm³ × 125 mg/dm³
= 31.25 mg
Hence, the mass of the dissolved solids in the river wayer is 31.25 M=mg.
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The diagram shows genetic structures.
Which label best represents the area marked Y?
chromosome
protein
gene
DNA
Answer:
The correct answer is - DNA (check image).
Explanation:
In this diagram, The W mark is the nucleus of the cell X is the chromosome Y represents the DNA and Z is the gene. Gene is the segment of the DNA and DNA is the pat of the chromosome with histone. Chromosomes are present in the nucleus of the cell. These all are the structures of the genetic structures.
Thus, the correct answer is - DNA.
Answer:
dna
Explanation:
edge
Methane, a highly flammable gas, is placed in a piston that has a volume of 2.1
L at STP. The piston then compresses the gas to 125 mL. What is the pressure
inside of the piston?
can somebody help me with this.
Answer:
HI
H₂O
H₃O⁺
I⁻
Explanation:
Bronsted-Lowry acids are chemicals that can donate protons, and Bronsted-Lowry bases are chemicals that can accept them. Conjugate bases and acids are the resulting effect of losing or gaining a proton in the form of H⁺.
What is the correct equilibrium constant expression for equation P2(g)
2 F20(g) = 2 PO(g) + 2 F2(g) ?
Answer:
k = [F2]² [PO]² / [P2] [F2O]²
Explanation:
In a chemical equilibrium, the equilibrium constant expression is written as the ratio between the molar concentration of the products over the molar concentration of the reactants. Each species powered to its reaction coefficient. For the equilibrium:
P2(g) + 2F2O(g) ⇄ 2PO(g) + 2F2(g)
The equilibrium constant, k, is:
k = [F2]² [PO]² / [P2] [F2O]²
The number of molecules of ammonia, NH₃, in water solution required for complete ionization of one molecule of sulfuric acid, H₂SO₄, is
1
2
3
4
6
Please Explain!!!
Answer:
6 that will be the answer
Two reasons that a plant from a rain forest would not survive in a desert home?
Answer: A planet from a rain forest would not survive in a desert home, for the fact they depend on water and as these live from water, without it, this leads to dehydration and with loss of water with plants, nothing is able to survive when it comes to a rain forest plant being in a desert home. Another reason is the high trees and leaves that are providing the plants enough sunlight or shade to grow, it guarantees to help keep the temperature normal. Being in a deserted area would mean that there would be a temperature change, something the plant is not used to. Without that needed shade and avoiding the scorching sun, they will die out from how different the temperature is, and how hot it is.
Explanation: I hope this helped you.
okay, the answer should be simple and easy, plants from a rainforest would not survive in a desert because the plants in the rainforest do get water, sunlight and air whereas the plants in the desert have Sunlight which is very hot. so if a plant in the rainforest was transferred to the desert it will hard to survive and it will eventually die because they will not get water that will be needed and the plant can get sunburns with the too hot temperature.
What percentage of a substance remains after 7 half-lives have passed?
A. 0.39
B. 2.5
C. 1.25
D. 0.78
Answer:
Not really sure, buts its either B or C.
I’m brain dead, anyone know this shi
Answer:
Option 1
Explanation:
p can hold upto 6 e-.
It would be easy if it gains 2e-, instead of losing 4e-, to be stable.
It gains 2e, and gets a charge of - 2e.
It forms O (2-)
For which substance is the standard heat of formation not equal to zero?
Hydrogen (H2)
Aluminum oxide (Al2O3)
Oxygen (O2)
Potassium (K)
Answer:
Aluminum oxide (Al₂O₃)
Explanation:
The standard heat (or enthalpy) of formation of a compound, is the amount of change in the enthalpy that takes place when 1 mole of the compound is produced from the elements it contains whereby the compounds and elements in the reaction are in their standard states
The standard state of an element, is the state in which the element is in the most stable form at a pressure of 1 bar
Therefore, the heat of formation of hydrogen, H₂, oxygen, O₂, and potassium, (K), will have a heat of formation of zero, while Al₂O₃ which is made of aluminum and oxygen in combining to form a compound in proportions which are different from their initial standard states will have a heat of formation not equal to zero
what is non polar covalent bond
Answer:
It is formed between two atoms of the same elements having same electronegativity in which the bonding electrons are equally shared between them. In this case, the centre of the positive charge coincides with the centre of the negative charge in theecular molecule. H, N: 0. etc. are the molecules in which non polar covalent bonds invalved. These substances are called non polar substances.
Answer:
A nonpolar covalent bond is a covalent bond in which the bonding electrons are shared equally between the two atoms. In a nonpolar covalent bond, the distribution of electrical charge is balanced between the two atoms.
Explanation:
A solute dissolved in water will cause
A the boiling point to increase
B the freezing point to increase
C the melting point to increase
D the boling point to decrease
(It’s A)
Answer:
A the boiling point to increase
Explanation:
That is a colligative property
Describe how plants and animals may change their characteristics in order to adapt to changes in their environment
please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Answer:
One way an animal may adapt to the environment and change characteristics is for example lizards. Lizards are preyed on by birds and other small mammmals. To avoid this some lizards have adapted to color changes or camofaluge.
Explanation:
Answer:
take a octopus for example, they change thw color of their skin to match their environment to stay hidden.
Explanation:
or take a decomposing plant for example, they mimik the process of decomposing to draw animals away
Determine the percent composition of Lithium in Li3PO3 (lower case BOTH 3)
Your answer:
A. 20.866%
B. 31.037%
C. 48.097%
D. 10.080%
Answer:
A. 20.866%
Explanation:
First, we calculate molar mass of Li3PO3
Molar mass of Li3PO3 = 6.9 (3) + 31 + 16(3)
= 20.7 + 31 + 48
= 99.7g/mol
To calculate the percent composition of Lithium, we say:
Mass of lithium in compound/mass of compound × 100
% composition = 20.7/99.7 × 100
= 0.208 × 100
= 20.8%.
A solution with a pOH of 4.3 has a [H+] of ??
please help
Answer:
A solution with a pOH of 4.3 has a [H+] of 2*10⁻¹⁰ M.
Explanation:
The pOH (or potential OH) is a measure of the basicity or alkalinity of a solution.
pOH indicates the concentration of hydroxyl ions [OH-] present in a solution. It is defined as the negative logarithm of the activity of hydroxide ions. That is, the concentration of OH- ions:
pOH= -log [OH-]
On the other hand, pH is also a measure of the basicity or alkalinity of a solution. POH is an indicator that is related to pH by:
pOH + pH= 14
So, if the solution has a pOH equal to 4.3, the pH is calculated by:
4.3 + pH= 14
pH= 14 - 4.3
pH= 9.7
The pH is defined as the logarithm of the concentration of H+ ions, with the sign changed:
pH= -log [H+]
So, in this case:
9.7= - log[H+]
Solving
[H+]= 2*10⁻¹⁰ M
A solution with a pOH of 4.3 has a [H+] of 2*10⁻¹⁰ M.
Please help this will determine my grade so I beg help me out and my grade
Answer:
C: checking your email
Explanation:
I believe that C would be impossible, as you cannot use wireless networks without radio waves
Calculate how many grams of sodium chloride we would need to make a solution with the same molarity of seawater, which is about 0.598 M.
Answer:
34.92 grams NaCl (in 1 L of solution)
Explanation:
The chemical formula of sodium chloride is NaCl. From the formula, we can calculate the molar mass of NaCl:
MM(NaCl)= MM(Na) + MM(Cl) = 23 g/mol + 35.4 g/mol = 58.4 g/mol
A solution of NaCl with a molarity of 0.598 M has 0.598 moles of NaCl per liter of solution. So, we multiply the moles by the molar mass of NaCl to calculate the mass we need:
mass of NaCl = 0.598 mol x 58.4 g/mol = 34.92 g NaCl
Therefore, we need 34.92 grams of NaCl to prepare 1 liter of a solution with a molarity of 0.598 M.
What is the number of moles in a sample of gas that has a volume of 3.5 L, a
pressure of 200 kPa, and a temperature of 300 K?
Explanation:
[tex]PV = nRT \\ (200000 \times 3.5 \times {10}^{ - 6} ) = n \times 8.314 \times 300 \\ n = \frac{0.07}{2494.2 } \\ n = 2.81 \times {10}^{ - 5} [/tex]
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What is the pH of 0.0000043M HNO3 ? (3 sig figs, round the last digit only if needed)
Answer:
pH = 5.37
Explanation:
We'll begin by obtaining the concentration of the hydrogen ion in the solution. This can be obtained as follow:
HNO₃ (aq) —> H⁺ (aq) + NO₃¯ (aq)
From the balanced equation above,
1 mole of HNO₃ produced 1 mole of H⁺.
Therefore, 4.3×10¯⁶ M HNO₃ will also produce 4.3×10¯⁶ M H⁺.
Finally, we shall determine the pH of the solution. This can be obtained as follow:
Concentration of Hydrogen ion [H⁺] = 4.3×10¯⁶ M
pH =?
pH = –Log [H⁺]
pH = –Log 4.3×10¯⁶
pH = 5.37
Therefore, the pH of the solution is 5.37
10) Which preparation produces a 2.0 M solution of Co
H1206? [molecular mass = 180.0]
(A) 180.0 g of C6H12O6 dissolved in 1000. mL of
solution
(B) 90.0 g of C6H1206 dissolved in 1000. mL of
solution
(C) 180.0 g of C6H1206 dissolved in 500.0 mL of
solution
(D) 90.0 g of C6H1206 dissolved in 500.0 mL of
solution
Answer:
(C) 180.0 g of C6H12O6 dissolved in 500.0 mL of solution
Explanation:
Molarity is mole/volume.
1. Find the mass of C6H12O6 in 1 Liter of 2.0 solution
(2 mol C6H12O6 / L) * (180 g / mol C6H12O6) = 360 g C6H12O6
There are 360 g C6H12O6 in 1000 mL of solution
2. Compare the value you found in step 1 to each of the multiple choice answers.
180.0 g of C6H12O6 dissolved in 500.0 mL of solution is exactly proportional to 360 g C6H12O6 in 1000 mL of solution.
The preparation which produces a 2.0 M solution of C₆H₁₂O₆ is 180.0 g of C₆H₁₂O₆ dissolved in 500.0 mL of solution.
How molarity is calculated?Molarity is defined as the number of moles of solute present in per liter of solution.
Moles of any substance will be calculated as :
n = W/M, where
W = given mass
M = molar mass
In the question given that molar mass of C₆H₁₂O₆ is 180 g/mole, and let we have produced the solution of 2 molarity by these amount in 1 liter i.e.
2 = n/1
n = 2 moles
Now by using these moles we can calculate the required mass of C₆H₁₂O₆ as:
2 = W/180
W = 360g
From this it is clear that for the preparation of 1 liter of solution of 2 molarity 360g of C₆H₁₂O₆ is required. So in 500mL of solution, 180 g of C₆H₁₂O₆ will use.
Hence, option (C) is correct i.e. 180.0 g of C₆H₁₂O₆ dissolved in 500.0 mL of solution.
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Arrange ionic compounds in order of decreasing amount of energy released in lattice formation .NaF,MgS,TLN and
The question is incomplete, the complete question is;
Arrange the following ionic compounds in order of decreasing amount of energy released in lattice formation: NaF, MgS, TlN, and CsI.
Answer:
TlN> MgS > NaF > CsI
Explanation:
Recall that lattice energy is the energy evolved when a crystal lattice is formed from its component ions.
The lattice energy depends on the size of the ions. The smaller the sizes of the ions, the larger the lattice energy.
The order of energy released in lattice formation for these compounds is;
TlN> MgS > NaF > CsI
The potential energy diagram for a reaction starts at 180 kJ and ends at 300 kJ. What type of reaction does the diagram best represent? (5 points)
Exothermic reaction
Endothermic reaction
Reaction between two solids
Reaction between two liquids
Answer:
Exothermic reaction
Explanation:
An exothermic process releases heat, causing the temperature of the immediate surroundings to rise
The potential energy diagram for a reaction starts at 180 kJ and ends at 300 kJ. the type of reaction does the diagram best represent exothermic reaction.
What is exothermic reaction?An exothermic reaction would be one in which heat energy is emitted. Exo stands for "evolve out." The term "thermos" refers to a container that holds heat. The term "exothermic" refers to a process in which heat is produced. In general, an exothermic reaction is one in which heat is released as a byproduct.
Therefore, the reaction diagram will represent exothermic reaction.
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Whilst Et₃CCl is unreactive towards water even at elevated temperatures, Et₃SiCl is hydrolyzed rapidly. Explain the origin of these differences and provide a reaction scheme with mechanistic details for the hydrolysis of Et₃SiCl.
Answer:
See Explanation
Explanation:
In discussing the reason why Et₃SiCl is more easily hydrolysed than Et₃CCl, we must remember that the electronegativity difference between silicon and chlorine is much higher than the electronegativity difference between carbon and chlorine.
As a result of this, the Si-Cl bond in Et₃SiCl is more polar and hence susceptible to attack by water than the C-Cl bond in Et₃CCl.
Also, it is postulated that the presence of vacant d orbitals on silicon assists hydrolysis in Et₃SiCl. Such vacant orbitals are absent in carbon hence Et₃CCl does not undergo hydrolysis.
The reaction scheme is shown in the image attached to this answer.
The rate constant for a first order reaction
is 2.80-10-35-1 at 60.0°C. The rate
constant at 45.0°C is 4.80.10-4 5-1. What
is the activation energy for the reaction?
[ ? ]kJ/mol
Recall that R = 8.314 J/mol K
Answer:
E_a = 103.626 × 10³ KJ/mol
Explanation:
Formula to solve this is given by;
Log(k2/k1) = (E_a/2.303R)((1/T1) - (1/T2))
Where;
k2 is rate constant at second temperature
k1 is rate constant at first temperature
R is universal gas constant
T1 is first temperature
T2 is second temperature
We are given;
k1 = 2.8 × 10^(-3) /s
k2 = 4.8 × 10^(-4) /s
R = 8.314 J/mol.k
T1 = 60°C = 333.15 K
T2 = 45°C = 318.15 K
Thus;
Log((4.8 × 10^(-4))/(2.8 × 10^(-3))) = (E_a/(2.303 × 8.314))((1/333.15) - (1/318.15))
We now have;
-0.76592 = -0.00000739121E_a
E_a = -0.76592/-0.00000739121
E_a = 103.626 × 10³ KJ/mol
The process by which particles in a solution spread out evenly is called?
Answer:
this is your answer.....