Answer:the Density is 0.22 and the Substance is Cork
Explanation:
A reaction takes place in a bomb calorimeter. if the calorimeter decreases in temperature over the course of the reaction, what are the signs of qcal and qrxn?
Answer:If the calorimeter decreases in temperature over the course of the reaction:
[tex]Q_{rxn}=Positive[/tex]
[tex]Q_{cal}=Negative[/tex](heat is lost by the caloriemter)
Explanation:
Whenever reaction takes place in calorimeter tone out of two things can a happen:
1. If the temperature of calorimeter increases: During a reaction when heat is released in the calorimter. This heat released is then absorbed by the calorimeter (Law of Conservation of Energy) which results in increase in temperature of calorimeter.
Those reaction which add on heat to their surrounding are termed as Exothermic reaction.
[tex]Q_{rxn}=Negative[/tex]
[tex]Q_{cal}=Positive[/tex] (Heat gained by the calorimeter)
2. If the temperature of calorimeter decreases: During a reaction when heat is lost from the calorimter. This heat loss is due to the absorption of heat by reactants during the reaction (Law of Conservation of Energy) which results in decrease in temperature of calorimeter.
Those reaction which absorbs heat from their surrounding are termed as Endothermic reaction.
[tex]Q_{rxn}=Positive[/tex]
[tex]Q_{cal}=Negative[/tex](heat is lost by the caloriemter)
What is formed when atoms of different elements are combined chemically?
Stand on a bathroom scale and read your weight. When you lift one foot up so you’re standing on one foot, does the reading change? Does a scale read force or pressure?
Write the identity of the missing nucleus for the following nuclear decay reaction: 18 9F→01e+?
Gold is a rare metal that is often blended with other metals to lower the cost of jewelry or art. What physical property of gold could help you determine if a piece is pure gold?
Answer:
Physical property is density.
Explanation:
This check needs precision. Gold is a dense metal, 19.32 grams per cubic centimeter. For that you have to calculate the density, weighing the piece on a scale, then you would fill a test tube with water and introduce the piece and note how much the water has risen. Density is defined as the mass divided by the displaced volume. If the result you get is close to 19 it will be a 24-karat gold piece.
The second shell in the ground state of oxygen contains how many electrons
The second electron shell of an atom can hold a maximum of ______ electron(s).
What is the water table?
A. a flat, table-like body of water
B. the bottom surface of underground water
C. the bottom layer of water in oceans, lakes, and rivers
D. the upper surface of underground water
Answer: Option (D) is the correct answer.
Explanation:
Water table is defined as the upper most level of water that is present under the ground surface where there is permanent separation of soil or rocks with water.
Water table is maintained through a natural process as when it rains then the rain water seeps through the ground and reaches below the ground.
Water table is also known as ground water table.
Therefore, we can conclude that the water table is the upper surface of underground water.
Why is hydrogen bonding only possible with hydrogen answer?
Identify the major functional groups for biomolecules and list compounds where each are found
Final answer:
The major functional groups for biomolecules include hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl. Examples of compounds where these functional groups are found include carbohydrates, amino acids, and organic acids.
Explanation:
The major functional groups for biomolecules include hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl. These functional groups confer specific chemical properties to molecules bearing them.
For example, hydroxyl groups (-OH) are found in carbohydrates, alcohols, and many other organic compounds. Amino groups (-NH2) are found in amino acids, the building blocks of proteins. Carboxyl groups (-COOH) are found in organic acids, such as fatty acids.
Carbohydrates are formed by dehydration synthesis, a process in which monomers bind together by combining their functional groups and generating water molecules as byproducts.
Which contribution added to Rutherford's discovery of a positive nucleus?
Atoms are indivisible.
Electrons are scattered in an atom.
Neutrons are inside the nucleus of an atom.
Atoms of the same element have the same properties.
Answer:
Neutrons are inside the nucleus of an atom.
Explanation:
which option is an example of a physical properties
flammability
pH
toxicity
freezing point
The correct answer would be freezing point. The other three would not be the answer because fammability, ph, and toxicity are all examples of chemical properties.
A solution is prepared by dissolving 4.68 g of nacl in enough water to produce 40.0 ml of solution. what is the molarity of nacl for the solution?
When water vapor becomes liquid water due to cooling, it is called _____?
9. A room measures 5 m x 20000 mm x 1000 cm. What is its volume in cubic cm?
Sea water, a solution composed of a variety of salts dissolved in water. the salt is the
How many grams of solid kcl are needed to prepare 250 ml of 0.235 m solution?
To prepare 250 mL of a 0.235 M solution of KCL, you would need roughly 4.38 grams of solid KCl. This is calculated using the formula for molarity, converting volume in ml to liters, and then using the molar mass of KCl to convert moles to grams.
Explanation:The task is to find out how many grams of solid KCl are needed to prepare 250 mL of 0.235 M solution. This is a question about molarity, which is a measure of the concentration of a solute in a solution.
Start by knowing that molarity (M) is defined as moles of solute per liter of solution. Hence, we can calculate the moles of KCl needed using the formula: moles = Molarity * Volume (in liters). In this case, the volume in litres is 250 mL / 1000 = 0.250 L.
Moles of KCl = Molarity * Volume
Moles of KCl = 0.235 M * 0.250 L = 0.05875 mol
Now to convert moles to grams, we use the molar mass of KCl, which is approximately 74.55 g/mol.
Mass of KCl = Moles * Molar mass
Mass of KCl = 0.05875 mol * 74.55 g/mol = approximately 4.38 g
So, you would need around 4.38 grams of solid KCl to prepare 250 mL of a 0.235 M solution.
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To prepare 250 mL of a 0.235 M solution of KCl, you need a. 4.38 grams of KCl.
To prepare 250 mL of a 0.235 M solution of KCl, you need 4.38 grams of KCl.
This is calculated by first finding the moles of KCl and then converting it to grams using the molar mass of KCl. Hence, 4.38 grams of KCl is required.To prepare 250 mL of a 0.235 M solution of KCl, you need to calculate the number of moles of KCl first and then convert that to grams.The formula to find moles is:
Moles = Molarity × Volume (in liters)Given:
Molarity (M) = 0.235 MVolume (V) = 250 mL = 0.250 LFirst, calculate the moles of KCl:
Moles of KCl = 0.235 M × 0.250 L = 0.05875 molesNext, convert the moles of KCl to grams using the molar mass of KCl.
Molar mass of KCl = 39.10 g/mol (K) + 35.45 g/mol (Cl) = 74.55 g/molCalculate the grams of KCl:
Grams of KCl = 0.05875 moles × 74.55 g/mol = 4.38 gramsTherefore, to prepare 250 mL of a 0.235 M solution of KCl, you need 4.38 grams of KCl.
Correct question is: How many grams of solid kcl are needed to prepare 250 ml of 0.235 m solution?
a. 4.38 g
b. 5.67 g
c. 3.67 g
d. 2.78 g
Which quantum number determines the energy of an electron in a hydrogen atom? which quantum number determines the energy of an electron in a hydrogen atom? l n e ml n and l?
A Hydrogen atom only contains a single electron (1 e). Therefore for this atom, the quantum number which determines the energy of an electron is best represented only by the principal quantum number. The principal quantum number has a symbol of n.
Answer:
n
The number of valence electrons found in an atom of a group a element is equal to
If an atom has 104 electrons, 157 neutrons, and 104 protons, what is its approximate atomic mass?
The atomic mass of the atom with 104 protons and 157 neutrons has been 261 amu.
An atom has been consisted of the positively charged nucleus and the negatively charged electrons revolving around the nucleus. The nucleus has been consisted of neutrons and protons.
The transfer of electrons between the atoms impart charge to the atom and helps in the reactivity of the atom. The atomic mass in an atom has been the mass of the nucleus. It has been a constant quantity in an atom.
Since the atomic mass has been the mass of the nucleus:
Atomic mass = Neutrons + Protons
Atomic mass = 157 + 104
Atomic mass = 261 amu
The atomic mass of the atom with 104 protons and 157 neutrons has been 261 amu.
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3 common items include solid liquid and gas
How many valence electrons are found in one atom of nitrogen (n)? 2 5 7 14?
When reaction with a chlorine atom, a sodium atom reacts by losing an electron to form the na+ ion, which is _________________________________________?
Which quantity is equivalent to 50 kilocalories
I believe this problem have these following choices:
5,000 cal
0.05 cal
5 x 10^3 cal
5 x 10 ^4 cal
Now 1 kilocalorie = 1000 calories, therefore:
50 kilocalories * (1000 calories / 1 kilocalorie) = 50,000 calories
Since there are 4 zeroes, so the scientific notation is:
5 x 10 ^4 cal (ANSWER)
In order to amend the Articles of Confederation, how many votes were needed? A) 7 B) 9 C) 10 D) 13
When water evaporates from salt is it a chemical or physical change?
Decide if the following definite article and noun agreement is CORRECT or INCORRECT
La mapa
Answer:
wrong in corect
Explanation:
my explanation is it would be el mapa
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Describe how the periodic trends of atomic radius, electronegativity, and ionization energy appear on the periodic table
is there more
to the senteance
it just cuts off
Periodic trends include the atomic radius, which decreases across a period and increases down a group; electronegativity, which increases across a period and decreases down a group; and ionization energy, which increases across a period and decreases down a group.
Periodic Trends: Atomic Radius, Electronegativity, and Ionization Energy
The periodic table is organized in such a way that certain properties of elements show predictable trends. These periodic trends include atomic radius, electronegativity, and ionization energy.
Atomic Radius
The atomic radius is the size of an atom. It generally decreases from left to right across a period due to the increase in the number of protons, which pulls the electrons closer to the nucleus. Conversely, the atomic radius generally increases from top to bottom within a group, as additional electron shells are added, making the atom larger.
Electronegativity
Electronegativity is an atom's ability to attract electrons. It generally increases from left to right across a period because atoms are more effective at attracting electrons due to their increased nuclear charge. In contrast, electronegativity decreases going down a group because the increased distance from the nucleus and the shielding effect make it harder to attract electrons.
Ionization Energy
Ionization energy is the energy required to remove an electron from an atom in its gaseous state. This energy increases from left to right across a period owing to stronger attraction between the nucleus and electrons. However, ionization energy decreases from top to bottom in a group because outer electrons are farther from the nucleus and more shielded by inner electrons, requiring less energy to remove them.
These periodic trends are critical for understanding elemental behavior and predicting chemical reactions.
Determine the volume of an object that has a mass of 455.6 g and a density of 19.3 g/cm3. 42.4 ml 23.6 ml 18.5 ml 87.9 ml 31.2 ml
The volume of the object is 23.06 cm³
We have an object of given mass and density.
We have to calculate the volume of this object.
How is the Mass and Density of a body related to each other?The following relation exists between mass and density -
m = d x v
d - density of body
m - mass of body
v - volume of body
According to the question -
m = d x v
Rewrite the relation as follows -
v = m/d
Substitute the values -
v = 455.6 / 19.3 = 23.06 cm³.
Hence, the volume of the object is 23.06 cm³.
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The factor that is changed throughout an experiment is called the _______. A. apparatus B. constant C. variable D. hypothesis
Answer:
C - Variable
Explanation:
Let’s see all the options in detail.
Apparatus: These are the equipment’s used in the experiment. Irrespective of the experiment result, the apparatus remains unchanged from start till the end.
Constant: These are factors that are fixed and does not change throughout the experiment.
Variable: A variable is any factor in an experiment that changes. As per dictionary, variable literally means something that varies i.e. change.
Hypothesis: This is the underlying explanation in response to which the experiment is being conducted. Also, in an experiment, the hypothesis is not considered a factor at all.
Therefore, the correct answer is C.