A student does not observe a change when holding a test tube in a flame. However, a change is expected. What is the most likely reason for this?
D. The reactants were not heated long enough.
What do all steroids have in common?
A. They are not lipids.
B. They are all built on a four-ring structure.
C. They all have the same function.
D. They are all sex hormones.
What is the molar mass of (NH4)2SO4
If 7.84 × 107 J of energy is released from a fusion reaction, what amount of mass in kilograms would be lost? Recall that c = 3 × 108 m/s.
7.06 × 1024
8.71 × 10-4
8.71 × 10-7
8.71 × 10–10
Answer:
The amount of mass in kilograms would be lost [tex]8.7111\times 10^{-10} kg[/tex].
Explanation:
Energy released during fusion reaction = [tex]7.84\times 10^7 J[/tex]
Mass of amount lost during the reaction = Δm
Speed of the light = c = [tex]3\times 10^8 m/s[/tex]
Using Einstein equation :
[tex]E=\Delta m\times c^2[/tex]
[tex]7.84\times 10^7 J=\Delta m\times (3\times 10^8 m/s)^2[/tex]
[tex]\Delta m=8.7111\times 10^{-10} kg[/tex]
The amount of mass in kilograms would be lost [tex]8.7111\times 10^{-10} kg[/tex].
Which of the following substances will cause the least temperature change if the same amount of each substance is added to 1.0 kg of water?
K3PO4
CuSO4
CH4OH
MgCl2
This is a question based on colligative property
colligative property is a property of solution which depends upon the number of molecules of solute and solvent
It is independent of nature of solute added to a particular solvent
The colligative properties are
a) elevation in boiling point
b) depression in freezing point
c) relative lowering of vapour pressure
d) osmotic pressure
As given we are adding same mount of each substance
Which means that we are adding same moles of each substance
the minimum number of particles will be produced by CH3OH (methanol) hence it will cause least temperature change.
The greatest change will be due to K3PO4
[07.01]When ammonia, NH3, dissolves in water, hydrogen ions are transferred from the water to ammonia to form ammonium ions and hydroxide ions. This reaction can be seen below: H2O (l) + NH3 (aq) OH- (aq) + NH4+ (aq) Which of the following helps to explain why ammonia is a base?
Ammonia acts as a Brønsted-Lowry base because it accepts a hydrogen ion from water, forming ammonium and hydroxide ions. It also satisfies the Arrhenius definition by increasing the concentration of hydroxide ions in the solution. Thus, the answer most appropriately corresponds to option b, Brønsted-Lowry definition.
When ammonia, [tex]NH_3[/tex], dissolves in water, it functions as a base according to the Brønsted-Lowry definition because it accepts a hydrogen ion (H+) from water to form ammonium ions ([tex]NH_4^+[/tex]) and hydroxide ions ([tex]OH^-[/tex]). Water acts as a Brønsted-Lowry acid in this reaction because it donates a hydrogen ion to the ammonia. This process forms a conjugate acid-base pair, with ammonia being the base that becomes the conjugate acid ([tex]NH_4^+[/tex]), and water being the acid that becomes the conjugate base ([tex]OH^-[/tex]). Additionally, ammonia also meets the Arrhenius definition of a base because the reaction results in an increase in the concentration of hydroxide ions in the solution. Thus, the answer most appropriately corresponds to option b, Brønsted-Lowry definition.
a race car driver drives 35 laps in 84 minutes what is the average laps per minute
when the volume of a gas is changed from _____ m3 to 15.5 m3 the temperature will change from 159 K to 456 K
the steps of scientific method in order are?
a. purpose , experiment, hypothesis , analysis , conclusion
b. purpose , hypothesis , experiment , analysis, conclusion
c. hypothesis , experiment , analysis, conclusion .
d. purpose, hypothesis, experiment , conclusion
why is it important to have a controlled experiment
What I said the molarity of an hcl solution if 24.0 ml is completely neutralized by 98.0 ml of 0.250m ca(oh)2
in which situation can a mixture always be called a solution
Answer: when the mixture is homogeneous
Explanation:
What cellular process converts solar energy into chemical energy
The gas in a cylinder has a volume of 8 liters at a pressure of 101 kPa. The pressure of the gas is increased to 213 kPa. Assuming the temperature remains constant, what would the new volume be?
Please show your work, thanks!
Which substance will most affect the freezing point of water if 1 mole of the substance is added to 1 kilogram of water?
The upper quartile of a set of data is a number that __________. A. separates the bottom half of the data set from the upper half B. finding the mean of the data set remaining after removing the lower half C. separates the lower quarter of the data set from the upper three-quarters D. separates the lower three-quarters of the data set from the upper quarter
Answer:
D. separates the lower three-quarters of the data set from the upper quarter
Explanation:
The upper quartile is a line or a point that divides the upper half of a set of data in two exact parts, so when you get the median of the whole set of data, you take the upper half and calculate the median of that upper half, dividing the upper half in quartiles, and you get the division between the upper quartile and the other three quartiles.
Consider the heating curve. In which region are most particles moving the fastest?
A) 2
B) 3
C) 4
D) 5
The particles are moving fastest in Region D) 5.
As temperature increases, so does the average kinetic energy (speed) of the molecules.
Answer: The correct option is (D)
Explanation:
As the temperature increases the energy of the particles increases which results in increase of kinetic energy of the particles. With this increase in energy particles moves more rapidly.
So, the particles at higher temperature will be moving at faster speed in region 5.
Covalent compounds:
a)are formed from one metal and one nonmetal
b) exchange electrons in a chemical bond
c) have a low melting point
d)have weaker bonds than ionic compounds
Which answer would be correct i think maybe B
The correct option is c i.e, have a low melting point. Covalent compounds have a low melting point due to weaker intermolecular forces. They are formed from two or more nonmetal elements and share electrons in a chemical bond.
Understanding the properties of covalent compounds is essential in Chemistry. Let's analyze each option provided:
Option A: Covalent compounds are not formed from one metal and one nonmetal. Instead, they are formed from two or more nonmetal elements.Option B: This option is incorrect because, in covalent bonds, atoms share electrons rather than exchange them.Option C: Covalent compounds indeed have a low melting point compared to ionic compounds. This is due to the weaker intermolecular forces present in covalent compounds.Option D: Correct. Covalent bonds generally have weaker bonds than ionic compounds, making it easier to melt or boil covalent compounds.Given the above explanations, the correct answer is Option C: Covalent compounds have a low melting point.
For the reaction Pb(NO3)2 + 2KI → PbI2 + 2KNO3, how many moles of lead iodide are produced from 246.2 g of potassium iodide?
To find out how many moles of lead iodide are produced from 246.2 g of potassium iodide, first convert the mass of KI to moles using its molar mass, then divide by the stoichiometric ratio from the reaction. It is found that 246.2 g of KI will produce 0.7415 moles of lead iodide.
To determine how many moles of lead iodide are produced from 246.2 g of potassium iodide (KI), it is necessary to consider the stoichiometry of the reaction given by:
[tex]Pb(NO_3)_2 (aq) + 2 KI (aq) \rightarrow PbI_2 (s) + 2 KNO_{3} (aq)[/tex]
First, we calculate the number of moles of KI using its molar mass:
1 mole KI = 166.0028 g/mol. Therefore,
Moles of KI = 246.2 g
166.0028 g/mol = 1.483 moles of KI
Since the reaction requires 2 moles of KI for every mole of [tex]PbI_2[/tex], we divide the moles of KI by 2 to find the moles of [tex]PbI_2[/tex]:
[tex]PbI_2[/tex]moles = 1.483 moles / 2 = 0.7415 moles of [tex]PbI_2[/tex]
Therefore, 246.2 g of KI will produce 0.7415 moles of lead iodide.
When an atom that has no charge loses two electrons, it becomes a:
A: positive ion.
B: negative ion.
C: positive isotope.
D: negative isotope.
Answer: Option (a) is correct.
Explanation:
It is known that electrons hold a negative charge. So, when the negative charge that is electrons are taken out an atom then the number of electrons become less in number as compared to the number of protons.
Hence, the atom attains a positive charge.
An isotope is formed when an atom shows same number of protons and different number of neutrons. So, when an atom loses 2 electrons there will be no change in the number of neutrons. Therefore, an isotope will not form.
Thus, it is concluded that when an atom with no charge loses two electrons, it becomes a positive ion.
Answer:
positive ion
Explanation:
neon has an average atomic mass of 20.2 g/mol, whereas argon has an average atomic mass of 40.0 g/mol. How would the number of atoms in a 1.0 mol sample of neon compare to the number of atoms in a 4.0 mol sample of argon
Answer : The number of atoms in a 4.0 mole sample of argon has greater number of atoms or four times as compared to the number of atoms in a 1.0 mole sample of neon.
Explanation :
As we know that the 1 mole of substance contains [tex]6.022\times 10^{23}[/tex] number of atoms.
As per question,
The 1 mole sample of neon contains [tex]6.022\times 10^{23}[/tex] number of atoms.
And,
As, 1 mole sample of argon contains [tex]6.022\times 10^{23}[/tex] number of atoms
So, 4.0 mole sample of argon contains [tex]4.0\times 6.022\times 10^{23}=24.088\times 10^{23}[/tex] number of atoms
From this we conclude that, the number of atoms in a 4.0 mole sample of argon has greater number of atoms or four times as compared to the number of atoms in a 1.0 mole sample of neon.
which of the following is not something that the atmosphere does for us ?
a. the atmosphere gives us air to breath
b. the atmosphere provides us protection
c. the atmosphere gives us gravity
d. the atmosphere provides us with weather
The concentration of 150.0 mL of Na2CO3 is found to be 30.0 ppm. What mass of Na2CO3 is dissolved in the solution if the density of the solution is 0.750 g/mL?
Answer:
c
Explanation:
3.38x10^-3G
don't answer if you're not 100%.
A compound differs from a mixture in that the compound
has two or more identities
has only one identity
is composed of only one kind of atom
can be separated by physical means.
A burning match is an example of a chemical change phase change nuclear change physical change
A burning match is an example of a chemical change. The transformation of two or more reactants into new compounds.
The term "chemical change" describes a process when one or more compounds are changed into new substances with new chemical properties. The atoms of the original substances rearrange themselves to establish new chemical bonds during a chemical transition, producing new molecules or compounds.
An illustration of a chemical change, in which two or more reactants are changed into new compounds, would be a burning match. Sulphur, wood, and oxygen combine to create smoke and ash when a match is lit.
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