When taking measurements, you must consider _____.
- accuracy, precision, and uncertainty
- only accuracy
- only precision
- only uncertainty
Example 1: urea, (nh2)2co, is used in the manufacture of resins and glues. when 5.00 g of urea is dissolved in 250.0 ml of water (d = 1.00 g/ml) at 30.0 c, 27.6 kj of heat is absorbed. (specific heat of water 4.18 j/g.c) is the solution process exothermic? what is ? what is the final temperature of solution?
trampoline and playground
When atoms are split, from which part of the atom is the energy released?
nucleus
electrons
isotopes
Answer: Option (a) is the correct answer.
Explanation:
It is known that an atom consists of three sub-atomic particles which are protons, neutrons, and electrons.
When an atom splits then only neutrons and protons are involved and no electrons are involved into the reaction.
Hence, energy is released by the nucleus of the atom. And, these type of reactions reactions are known as nuclear reactions.
For example, [tex]^{16}_{8}O + ^{1}_{1}n \rightarrow ^{13}_{7}N + ^{4}_{2}He[/tex]
Whereas isotopes are the species which have same atomic number but different mass number.
Thus, we can conclude that when atoms are split, from nucleus of the atom is the energy released.
In the diagram, above, marker D is pointing to a __________, which is a landform that forms when a river slows down as it flows into an ocean or lake. As the river slows, it drops its sediment load, gradually creating a network of small channels and islands.
You need to measure the brightness of a light bulb using the metric system. In which unit do you express your measurement?
A. meter
B. liter
C. kilogram
D. candela
***My answer: D. Candela
because candela is the unit of light intensity...
idk if that applies here?? :) please explain!! thanks :)
Part a use valence bond theory to devise a hybridization and bonding scheme for co2. match the words in the left column to the appropriate blanks in the sentences on the right. make certain each sentence is complete before submitting your answer.
Silver has a density of 10.5 g cm3 and gold has a density of 19.3 g/cm3. which would have the greater mass, 5cm^3 of silver or 5cm^3 of gold?
A sample of neon occupies a volume of 375 ml at stp. What will be the volume of neon If the pressure is reduced to 90.0 KPA?
A. 422 ml
B. 422 L
C. 333 ml
D. 333 L
At STP conditions value of absolute pressure is 101.325 kPa.
From the given data we can determine the new volume of neon using following proportion:
V : V1 = p : p1
375 : V1 = 101.325 : 90
101 * V1 = 90 * 375
V1 =33750/101 =333ml
Which of these agreements has goals of peace and shared scientific research?
A. Environmental Protection Treaty
B. Migratory Bird and Game Mammal Treaty
C. Antarctic Treaty System
D. Ramsar Convention
Option C, Antarctic Treaty System, is the right answer.
The Antarctic Treaty System, control global connections with regard to Antarctica; the only continent of the earth without the native population of human beings. In other words, the ATS is the entire system of adjustments developed for the intention of managing associations among states in the Antarctic. The main goal of the ATS is to guarantee "in the affair of all humankind that Antarctica shall proceed always to be practised completely for peaceful objectives and shall not become the view or gadget of universal disharmony.
Answer:
The correct answer is "Antarctic Treaty System"
Explanation:
The Antarctic treaty system signed the first arms control agreement. It bans any form of military agreement on the Antarctic, and promotes free scientific investigation. The treaty was signed by 12 countries during the era of the cold war. The only use of military is for peaceful purposes and scientific investigations. It promotes free exchange of scientific knowledge and personnel.
A rigid vessel at constant temperature initially contains 0.600 atm nitrogen gas and 0.600 atm hydrogen gas. if these gases react to form ammonia and the reaction goes to completion, which choice is closest to the final total pressure after the reaction?
The final total pressure after the completion of reaction is [tex]\boxed{0.8{\text{ atm}}}[/tex].
Further Explanation:
Stoichiometry:
The amountof species present in the reaction is determined with the help of stoichiometry by the relationship between reactants and products.
Balanced chemical reaction between nitrogen and hydrogen is as follows:
[tex]{{\text{N}}_{\text{2}}} + 3{{\text{H}}_2} \to 2{\text{N}}{{\text{H}}_{\text{3}}}[/tex]
This balanced reaction’s stoichiometry clearly indicates that one mole of nitrogen reacts with three moles of hydrogen to produce two moles of ammonia.
Since pressure is directly related to number of moles of gas, pressure required by hydrogen to react with one mole of nitrogen should be three times of pressure of nitrogen.
Therefore pressure of hydrogen can be calculated as follows:
[tex]\begin{aligned}{\text{Pressure of hydrogen}} &= 3\left( {0.600{\text{ atm}}} \right) \\&= 1.8{\text{ atm}} \\\end{aligned}[/tex]
But pressure of hydrogen in the rigid vessel is 0.600 atm only so it behaves as limiting reactant and its amount will govern the amount or quantity of product formed (ammonia).
Since the ratio of pressures of hydrogen and ammonia is 3:2, pressure of ammonia can be calculated as follows:
[tex]\begin{aligned}{\text{Pressure of ammonia}} &= \left( {\frac{2}{3}} \right)\left( {0.600{\text{ atm}}} \right) \\&= 0.4{\text{ atm}} \\\end{aligned}[/tex]
Pressure of unreacted nitrogen can be calculated as follows:
[tex]\begin{aligned}{\text{Pressure of unreacted nitrogen}} &= \left( {\frac{2}{3}} \right)\left( {0.600{\text{ atm}}} \right) \\&= 0.4{\text{ atm}} \\\end{aligned}[/tex]
Therefore total final pressure after the reaction can be calculated as follows:
[tex]\begin{aligned}{\text{Total final pressure}} &= \left( {0.4 + 0.4} \right){\text{ atm}} \\&= {\text{0}}{\text{.8 atm}} \\\end{aligned}[/tex]
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Answer details:
Grade: Senior School
Subject: Chemistry
Chapter: Mole concept
Keywords: stoichiometry, NH3, H2, N2, pressure, hydrogen, nitrogen, ammonia, 0.4 atm, 1.8 atm, 0.600 atm, 3H2, 2NH3, 0.8 atm.
In what three catagories can chemical reactions be classified
Hydrazine (n2h4) is used as rocket fuels. it reacts with oxygen to form nitrogen and water. write the balanced equation for this reaction. n2h4 + o2 → n2 +2h2o how many liters of n2 at stp form when 100g of n2h4 reaction with 100g of o2? how many grams of the excess reagent remain after the reaction?
The answer is: volume of nitrogen is 70L.
Chemical reaction: N₂H₄ + O₂ → N₂ + 2H₂O.
m(N₂H₄) = 100 g; mass of hydrazine.
M(N₂H₄) = 32 g/mol; molar mass of hydrazine.
n(N₂H₄) = m(N₂H₄) ÷ M(N₂H₄).
n(N₂H₄) = 100 g ÷ 32 g/mol.
n(N₂H₄) = 3.125 mol; amount of hydrazine.
m(O₂) = 100 g; mass of oxygen.
M(O₂) = 32 g/mol; molar mass of oxygen.
n(O₂) = 100 g ÷ 32 g/mol.
n(O₂) = 3.125 mol; amount of oxygen.
From chemical reaction: n(O₂) : n(N₂) = 1 : 1; n(O₂) = n(N₂).
n(N₂) = 3.125 mol; amount og nitrogen gas.
V(N₂) = n(N₂) · Vm.
Vm = 22.4 L/mol; molar volume.
V(N₂) = 3.125 mol · 22.4 L/mol.
V(N₂) = 70 L.
There is not excess reagent, because hydrazine and oxygen are all used in chemical reaction.
Based on a kc value of 0.200 and the given data table, what are the equilibrium concentrations of xy, x, and y, respectively? express the molar concentrations numerically.
Without additional data from the data table regarding initial concentrations and change, we cannot calculate the equilibrium concentrations of XY, X, and Y based on the provided Kc value. An ICE table and the presumed small value of x in concentration changes are needed to employ the equilibrium constant effectively.
To calculate the equilibrium concentrations of XY, X, and Y based on the given Kc value of 0.200, we need additional data from the data table. The statement mentions XY, X and Y but only provides information about X2, Y2, and Ke. Assuming we are dealing with a chemical equilibrium that can be represented as:
X2 + Y2 → 2XY
A mathematical expression for the equilibrium constant Kc can be written as:
[tex]Kc = [XY]^2 / ([X2][Y2])[/tex]
Since an ICE table and initial concentrations are not provided in the question, we cannot calculate the equilibrium concentrations without that information. Additionally, Ke may refer to the equilibrium constant in terms of pressure (Kp), so it's unclear how to proceed without more context. The provided value of Ke or Kc needs to be used with the initial concentrations to determine equilibrium concentrations after setting up an ICE (Initial, Change, Equilibrium) table. Typically, to find x (the change in concentration), we assume x is small and can be ignored in the expressions (0.78 - x) and (0.21 - x) considering the very small Kc value, leading to a simplification in solving the equation for x, if applicable.
SUPER EASY!
12 POINTS
Choose all that apply.
Which of the following contribute to your body's digestive process?
muscle
movements
chemical reactions
physical processes
respiration
Which of these items best describes the arrangement of electrons in an atom of sulfur? A. Two electrons in its first energy level; eight electrons in its second energy level; six valence electrons in its outermost energy level B. Two electrons in its first energy level; two electrons in its second energy level; eight electrons in its third energy level; four valence electrons in its outermost energy level C. Two valence electrons in its first energy level; eight electrons in its second energy level; six electrons in its outermost energy level D. Eight electrons in its first energy level; eight valence electrons in its outermost shell
THE ANSWER TO THIS QUESTION IS B IF YOU USING PF
A compound has the empirical formula CH2O. If the compound’s molecular mass is 180 g/mol, determine the molecular formula of the compound. Be sure to show your work.
A carbon compound X turns blue litmus to red and has a molecular formula C2H4O2.Identify X and draw its structure.Write a chemical equation for the reaction and name of the product formed in each case when X reacts with
a. ethanol in the presence of conc.H2SO4 (
b. sodium carbonate
Answer: Substance X is ethanoic acid and the reactions are given below.
Explanation:
A compound having molecular formula of [tex]C_2H_4O_2[/tex] which turns blue litmus to red is considered as an acid.
The compound is ethanoic acid which is generally termed as acetic acid.
Thus, the compound X is acetic acid.
The chemical equations for the reaction of X with
a. Ethanol in the presence of [tex]H_2SO_4[/tex]When acetic acid reacts with etahnol in the presence of an acid, it leads to the formation of a fruity smelling compound known as ester which is ethyl acetate.
[tex]CH_3COOH+CH_3CH_2OH\xrightarrow[]{H_2SO_4}CH_3COO-CH_2CH_3+H_2O[/tex]
b. Sodium carbonateWhen acetic acid reacts with sodium carbonate, it leads to the formation of sodium acetate, carbon dioxide and water.
[tex]2CH_3COOH+Na_2CO_3\rightarrow 2CH_3COONa+CO_2+H_2O[/tex]
The solar system formed from the
A. grouping together of asteroids.
B. explosion of an interstellar sun.
C. collision of two massive stars.
D. collapse of an interstellar cloud.
How many calories of heat energy are required to melt 20 grams of ice at 0 °c?
fast-moving glaciers that can move up to 6 kilometers per year.
Surging glaciers experience a significant increase in movement, moving at speeds much faster than the average glacier.
A glacial surge is a sudden increase in the speed of a glacier, often moving tens of meters per day, which is significantly faster than the typical glacier movement. Glaciers generally move by pseudo-plastic flow and their velocity is greatest at the surface, tapering off towards the base due to internal deformation and basal slipping. While average glacier speed is around 10 inches per day, surging glaciers can greatly exceed this, with some known to move up to 6 kilometers per year.
Notable examples of surging glaciers include the Hubbard Glacier, which in 1986 surged across the Russell fjord, and Greenland's fast-moving Jakobshavn glacier. Surging can be caused by various factors, but one believed to be significant is the buildup of water pressure beneath the glacier, which effectively 'floats' the ice, letting it slip over the bedrock. The presence of looped moraines on the glacier surface is a key indicator of a surging glacier.
Which of these practices does the most to keep wind and water from carrying away topsoil?
A. Crop rotation
B. Integrated pest management
C. Drip irrigation
D. Cover crops
Answer:
The correct answer is Cover Crops
What is the oxidation state of an individual nitrogen atom in nh4oh ? express the oxidation state numerically (e.g., +1)?
The oxidation state of an individual nitrogen atom in NH4OH is -3, determined by the rules for assigning oxidation states, where hydrogen is +1 and the ammonium ion has an overall charge of +1.
Explanation:The oxidation state of an individual nitrogen atom in NH4OH can be calculated using the rules for assigning oxidation states. The compound NH4OH consists of the ammonium ion (NH4+) and the hydroxide ion (OH-). To find the oxidation state of nitrogen, we consider that hydrogen generally has an oxidation state of +1 when combined with nonmetals and oxygen has an oxidation state of -2. In NH4+, with four hydrogen atoms, each hydrogen atom contributes +1, for a total of +4. To balance this and give the overall charge of the ammonium ion (+1), the nitrogen must have an oxidation state of -3.
Furthermore, in OH-, the oxygen has an oxidation state of -2, and the single hydrogen has an oxidation state of +1. But since we are only interested in the nitrogen atom, we focus only on the NH4+ part of NH4OH. So, the oxidation state of an individual nitrogen atom in NH4OH is -3.
Which renewable energy source depends on changing water levels?
What new inforamtion can you add the your definition of physical change?
What is my theoretical yield (in moles) of Potassium Bromide (KBr) if I start with 40 grams of Iron (II) Bromide [FeBr2]? moles KBr
The ksp of cadmium carbonate, cdco3, is 1.0 × 10-12. calculate the solubility of this compound in g/l.
The solubility of cadmium carbonate, CdCO3, in a 0.010-M solution of cadmium bromide can be calculated using the compound's Ksp value. The molar solubility is found to be 1.0 × 10^-6 M. Converting this to grams per liter gives a solubility of 1.724 × 10^-4 g/L.
Explanation:The solubility of cadmium carbonate, CdCO3, can be determined using the Ksp value. The Ksp value represents the product of the concentrations of the dissolved ions in a saturated solution. In this case, the Ksp of CdCO3 is 1.0 × 10^-12. Since the compound dissociates into Cd2+ and CO3^2- ions, the solubility can be calculated by assuming x as the molar solubility of CdCO3. Thus, [Cd2+] = x and [CO3^2-] = x. Plugging in these values into the Ksp expression, we get:
(x)(x) = 1.0 × 10^-12
x^2 = 1.0 × 10^-12
x = √(1.0 × 10^-12) = 1.0 × 10^-6 M
Since the question asks for the solubility in g/L, we need to convert the molar solubility to grams per liter. We can use the molar mass of CdCO3, which is approximately 172.4 g/mol. Therefore, 1.0 × 10^-6 M is equivalent to 1.724 × 10^-4 g/L.
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In which medium would light have the longest wavelength? water air glass diamond
the answer is b air
what is the sequence in which energy is converted to allow a gasoline-powered car to move.
The energy conversion or the energy transformation is the process of changing one form of energy to another , the energy produces certain changes within a system , Changes in the total energy of systems can only be accomplished by adding or removing the energy from them as the energy is a quantity which is conserved ( unchanging ) .
The internal combustion engine in the car converts the potential chemical energy in gasoline and oxygen into thermal energy which is transformed into the mechanical energy that accelerates the vehicle ( increasing its kinetic energy ) by causing the pressure and performing the work on the pistons .
What is the molar mass of the empirical formula for a compound with the formula C6H12Cl2O2
The molar mass of the empirical formula CH2ClO for the compound C6H12Cl2O2 is 65.476 g/mol, calculated by summing the atomic masses for carbon, hydrogen, chlorine, and oxygen.
The student is asking about the molar mass of the empirical formula for a compound with the formula C6H12Cl2O2. An empirical formula represents the simplest whole-number ratio of the elements within a compound.
For the given compound, its empirical formula is CH2ClO. To find the molar mass of this empirical formula, we sum the atomic masses of each element, adjusting for the number of atoms present. The atomic masses are approximately 12.01 g/mol for carbon (C), 1.008 g/mol for hydrogen (H), 35.45 g/mol for chlorine (Cl), and 16.00 g/mol for oxygen (O).
The calculation is as follows:
(1 \\u00d7 12.01 g/mol) for C(2 \\u00d7 1.008 g/mol) for H(1 \\u00d7 35.45 g/mol) for Cl(1 \\u00d7 16.00 g/mol) for OAdding them together, the molar mass of the empirical formula CH2ClO is:
12.01 + (2 \\u00d7 1.008) + 35.45 + 16.00 = 65.476 g/mol.
Therefore, the molar mass of the empirical formula for the compound is 65.476 g/mol.
what would you notice about the dot diagram of an unstable element?
The dot diagram of an unstable element has incompletely filled shell that is it will not have 8 dots which represent a stable octet.
What is an element?
It is defined as a substance which cannot be broken down further into any other substance. Each element is made up of its own type of atom. Due to this reason all elements are different from one another.
Elements can be classified as metals and non-metals. Metals are shiny and conduct electricity and are all solids at room temperature except mercury. Non-metals do not conduct electricity and are mostly gases at room temperature except carbon and sulfur.
The number of protons in the nucleus is the defining property of an element and is related to the atomic number.All atoms with same atomic number are atoms of same element.
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