Which of the following are indicators of a chemical change? Select all that apply.
color change
temperature change
precipitate formation
gas formation
cutting a solid into smaller pieces
Select the incorrect statement.
The physical properties of a compound are similar to those of its elements.
The boiling point of a compound is different from the individual elements.
The melting point of a compound is different from the individual elements.
Density is a physical property.
Answer:
The incorrect statement is:
The physical properties of a compound are similar to those of its elements.
Explanation:
The physical properties of a compound depend on its elements but they are not similiar to the physical properties of individual elements.
Take water as an example. Water is made by oxygen and hydrogen (H₂O). At normal , water is liquid and both oxygen and hydrogen are gases.
how many moles of 18L of NH3 at 30 celcius and 912 mmHg? how many grams?
In the chemical reaction: 2 h 2 (g) o2 (g) → 2 h2o (g), with 8 grams of h 2 (2 grams/mole) and 16 grams of o2 (32 grams/mole) and the reaction goes to completion, what is the excess reactant and how much of that would remain
How many grams of carbon dioxide are produced from the combustion of 1.3 moles of acetylene
Phosphorus has an atomic mass of 31 and an atomic number of 15, so the number of neutrons must be _______________.
sorry i'm late:
16 (how to get answer is shown below on second photo):
Energy is released during which phase changes
This is for a study guide for my semester final, and I have no clue how to answer this, please help, and please at least try to help!
Besides the major types of radioactive decay, there are two others: positron emission and electron capture.
• Compare and contrast positrons with electrons.
• Explain how positron emission works and how it causes transmutations.
• Explain how electron capture works and how it causes transmutations.
• Compare the transmutations caused by positron emissions and electron capture.
Positron emission = emission of a positron and a neutrino when a proton is convert into a neutron. The total number of particles in the nucleus doesn't change, -1 proton +1 neutron
It's a spontaneous reaction for some nucleus.
eg:
Positron = e+
Neutrino=ve
O-15 --> N-15 + e+ +ve
Electron capture= A nucleus absorb an electron while a proton is convert in a neutron and emit a neutrino. The total number of particles in the nucleus doesn't change, -1 proton +1 neutron
eg:
Al-26 +e- --> Mg-26 + ve
Electron capture and positron emission are two mechanisms to explain the decay of some unstable isotopes. Electron capture is usually observed when the energy difference between the initial and final state is low. Mainly because of the larger amount of kinetic energy need for the expulsion two particles with the positron emission mechanism.
Night-vision goggles work by detecting ________ when it's dark outside.
A. visible light
B. radio waves
C. ultraviolet light
D. infrared radiation
Final answer:
Night-vision goggles use infrared radiation to create visible images in low light or total darkness by detecting the thermal energy emitted by objects, which is more intense in the infrared spectrum.
Explanation:
Night-vision goggles work by detecting infrared radiation when it's dark outside. This technology relies on the thermal energy emitted by objects, which is more intense in the infrared spectrum and is not visible to the human eye. Unlike visible light, infrared radiation can be detected in low-light conditions or even in total darkness, allowing night-vision devices to create a visible image for the user.
Infrared radiation is part of the electromagnetic spectrum. Your eyes cannot see infrared radiation, but it can be felt as warmth on the skin. For example, reptiles can detect infrared radiation emitted by their prey, even though it's outside the human visual spectrum. Night-vision technology harnesses this invisible radiation to provide visibility in the absence of light.
The correct answer to the question is therefore D. Infrared radiation.
Wood, Iron, Glass, Paper, Nickel Which substances show magnetic property?
What are three ways that carbon atoms can be arranged in hydrocarbon molecules?
Determine the molecular formula of a compound having the empirical formula C9H17O and a molar mass of 847.56g/mol.
Calculate the mass of water produced when 4.86 g of butane reacts with excess oxygen.
When 4.86g of butane reacts with excess oxygen, 7.53g of water is produced. This calculation is based on stoichiometry principles and the balanced chemical equation of the reaction.
Explanation:The subject of this question is Chemistry and it pertains to the reaction of butane (C4H10) with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O). The balanced chemical equation for this reaction is 2C4H10 + 13O2 -> 8CO2 + 10H2O. The mass of water produced can be calculated through stoichiometry, which is the method of calculating the quantitative/weight relations of reactants and products in a chemical reaction.
Given the weight of butane is 4.86g, we first need to convert this to moles. The molar mass of butane is calculated by adding the molar masses of Carbon (C=12.01g/mol) x 4 and Hydrogen (H=1.01g/mol) x 10. This equals approximately 58.12g/mol. Therefore, the number of moles of butane we have is 4.86g / 58.12g/mol = 0.0836 moles.
From the balanced equation, we can see that two moles of butane produce ten moles of water. Therefore, 0.0836 moles of butane would produce 0.0836 x 10/2 = 0.418 moles of water. To convert this to mass, we multiply by the molar mass of water, which is 18.01g/mol. Hence, 0.418 moles x 18.01g/mol = 7.53g of water.
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The reaction of 4.86 g of butane with excess oxygen produces approximately 7.53 g of water. This is determined using the molar mass of butane, the balanced chemical equation, and stoichiometry.
Explanation:The chemical reaction of butane (C₄H₁₀) with oxygen (O₂) to produce carbon dioxide (CO₂) and water (H₂O) is given by the balanced equation 2C₄H₁₀ + 13O₂ -> 8CO₂ + 10H₂O. In this reaction, 2 moles of butane produce 10 moles of water. The molar mass of butane is 58.12g/mole. Thus, 4.86 g of butane is 4.86 g / 58.12 g/mole = 0.0836 moles.
By stoichiometry, 0.0836 moles of butane would produce 0.0836 moles x (10 moles of water / 2 moles of butane) = 0.418 moles of water. As the molar mass of water is approximately 18.02 g/mole, the mass-produced would be 0.418 moles x 18.02 g/mole = 7.53 g. Thus, 4.86 g of butane reacts with excess oxygen to produce approximately 7.53 g of water.
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Gas in a balloon occupies 3.3 L. What volume will it occupy if the pressure is changed from 100.0 kPa to 90.0 kPa (at constant temperature).
When the pressure is decreased from [tex]100.0 kPa[/tex] to [tex]90.0 kPa[/tex] at constant temperature, the volume of the gas in the balloon increases to [tex]3.67 L[/tex].
To solve this problem, we can use Boyle's Law, which states that for a given mass of gas at constant temperature, the volume of the gas is inversely proportional to its pressure. Mathematically, this can be expressed as:
[tex]\[ P_1V_1 = P_2V_2 \][/tex]
where [tex]\( P_1 \)[/tex] and [tex]\( V_1 \)[/tex] are the initial pressure and volume, and [tex]\( P_2 \)[/tex] and [tex]\( V_2 \)[/tex] are the final pressure and volume, respectively.
Given:
Initial volume [tex]\( V_1 = 3.3 \) L[/tex]
Initial pressure [tex]\( P_1 = 100.0 \) kPa[/tex]
Final pressure [tex]\( P_2 = 90.0 \) kPa[/tex]
Temperature is constant
We want to find the final volume [tex]\( V_2 \)[/tex]. Rearranging Boyle's Law to solve for [tex]\( V_2 \)[/tex], we get:
[tex]\[ V_2 = \frac{P_1V_1}{P_2} \][/tex]
Substituting the given values:
[tex]\[ V_2 = \frac{100.0 \text{ kPa} \times 3.3 \text{ L}}{90.0 \text{ kPa}} \][/tex]
[tex]\[ V_2 = \frac{330}{90} \text{ L} \][/tex]
[tex]\[ V_2 = 3.67 \text{ L} \][/tex]
What is the molarity of a solution that contains 3.25 moles of nano3 in 250. ml of solution?
The molarity of the solution is determined by dividing the number of moles of solute by the volume of the solution in liters, resulting in a molarity of 13.0 M for the sodium nitrate (NaNO3) solution.
Explanation:To calculate the molarity of the NaNO3 solution, we will use the formula of molarity, which is the number of moles of solute divided by the volume of the solution in liters. The student has provided that there are 3.25 moles of NaNO3 in 250 mL of solution.
To use the formula, we must convert the volume from milliliters to liters. Since 1000 mL equals 1 L, we divide the volume provided by 1000.
Volume in liters = Volume in mL / 1000 = 250 mL / 1000 = 0.250 L
Now, using the molarity formula:
Molarity (M) = Moles of solute / Volume of solution in liters = 3.25 moles / 0.250 L
M = 13.0 M
Explain how deforestation can cause a disruption to the carbon cycle
Deforestation disrupts the carbon cycle by reducing the removal of carbon dioxide from the atmosphere through photosynthesis and releasing stored carbon through burning wood and fossil fuels. This contributes to climate change.
Explanation:Deforestation can cause a disruption to the carbon cycle in several ways. Firstly, trees and plants remove carbon dioxide from the atmosphere and store it in their structure through photosynthesis. When forests are cleared, this process is reduced, leading to increased levels of carbon dioxide in the atmosphere. Additionally, the burning of wood and fossil fuels during deforestation releases stored carbon back into the atmosphere. These disruptions to the carbon cycle contribute to climate change and an imbalance in the Earth's temperature regulation.
Keywords: deforestation, carbon cycle, climate change, carbon dioxide, photosynthesis
Which substance is acting as the Brønsted-Lowry acid in the following chemical reaction? NH4 + OH- yields NH3 + H2O
A. NH4+
B. OH-
C. NH3
D. H2O
how many parts per million of mercury are there in a sample of tap water with a.mass of 750 g containing 2.2 mg of hg
We wish to dilute some 18.4 m h2so4 solution to make 600 ml of a 0.1 m h2so4 solution. how much of the 18.4 m solution should we start with?
We should start with approximately [tex]3.10 ml[/tex] of the [tex]18.4 M[/tex] [tex]H\(_2\)SO\(_4\)[/tex] solution to make [tex]600 ml[/tex] of a [tex]0.1 M[/tex] [tex]H\(_2\)SO\(_4\)[/tex] solution.
To solve this problem, we can use the dilution formula:
[tex]\[ C_1V_1 = C_2V_2 \][/tex]
where:
[tex]\( C_1 \)[/tex] is the concentration of the stock solution ([tex]18.4 M[/tex] [tex]H\(_2\)SO\(_4\)[/tex]).
[tex]\( V_1 \)[/tex] is the volume of the stock solution we need to use (unknown).
[tex]\( C_2 \)[/tex] is the concentration of the final solution ([tex]0.1 M[/tex] [tex]H\(_2\)SO\(_4\)[/tex]).
[tex]\( V_2 \)[/tex] is the volume of the final solution ([tex]600 ml[/tex] or [tex]0.6 L[/tex]).
We want to find [tex]\( V_1 \)[/tex], so we rearrange the formula:
[tex]\[ V_1 = \frac{C_2V_2}{C_1} \][/tex]
Now, plug in the values:
[tex]\[ V_1 = \frac{(0.1 \text{ M})(0.6 \text{ L})}{18.4 \text{ M}} \][/tex]
[tex]\[ V_1 = \frac{0.06}{18.4} \][/tex]
[tex]\[ V_1 =0.00326 \text{ L} \][/tex]
Since [tex]1 L = 1000 ml[/tex], we convert [tex]\( V_1 \)[/tex] to milliliters
[tex]\[ V_1 = 0.00326 \text{ L} \times 1000 \text{ ml/L} \][/tex]
[tex]\[ V_1 = 3.26 \text{ ml} \][/tex]
Rounding to two decimal places, we find that we need approximately [tex]3.10 ml[/tex] of the [tex]18.4 M[/tex] [tex]H\(_2\)SO\(_4\)[/tex] solution to make [tex]600 ml[/tex] of a [tex]0.1 M[/tex][tex]H\(_2\)SO\(_4\)[/tex] solution.
Question 1 how much water would you add to 175 ml of 6.00 m hydrochloric acid to prepare a 2.00 m solution of this acid? 350 ml 700. ml 58.3 ml 525 ml none of the above
Answer:
350 mL
Explanation:
Given:
concentration of stock solution of HCl =6.00 M
Volume of stock solution of HCl = 175 mL
concentration of required solution = 2.00 M
total volume of required solution = to be determined
This is problem of dilution. We have to determine the total volume of required solution to be made, from the given stock solution.
We will use
M₁V₁=M₂V₂
Where
M₁=concentration of stock solution
V₁= volume of stock solution
M₂=concentration of required solution
V₂=volume of required solution
Putting values
6X175=2XV₂
V₂=525 mL
so total volume of required solution formed will be 525 mL
We have already 175 mL of solution in it. The water need is difference of these two volume.
water added = 525-175= 350 mL
Is it possible to get the elliptic discriminate of an elliptic curve with characteristic 2?
What is the term for a substance that acts on proton donor in one reaction and as a proton acceptor in another?
Which phase(s) would experience an increase in the rate of dissolution with an increase in temperature?
A. gases only
B. solids only
C. liquids only
D. both solids and liquids
Increasing ratios of oxygen-18 to oxygen-16 in glacial ice indicate ________.
a. advancing ice sheets
b. warming temperatures
c. increased volcanic emissions
d. uplift of land surfaces
An increased ratio of oxygen-18 to oxygen-16 in glacial ice indicates warming temperatures as oxygen-18 is a heavier isotope and precipitates less readily in cold conditions.
Explanation:The ratio of oxygen-18 to oxygen-16 in glacial ice is often used as an indicator of past climatic conditions. When this ratio is increasing, it typically indicates warming temperatures.
This is because oxygen-18 is a heavier isotope that precipitates less readily in cold conditions
Therefore, a higher ratio of oxygen-18 suggests that it was warm enough for more of this heavier isotope to precipitate. So, the correct answer is b. warming temperatures.
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Which statement about the following reaction is correct?
CH4 (g) + 2O2 (g) yields CO2 (g) + 2H2O(l) deltaH = -890 kJ
reacting one mole of oxygen (O2) absorbs 445 kJ of energy
reacting one mole of oxygen (O2) releases 445 kJ of energy
reacting one mole of methane (CH4) absorbs 890 kJ of energy
reacting two moles of methane (CH4) releases 890 kJ of energy
Final answer:
The correct statement is that reacting one mole of oxygen (O2) releases 445 kJ of energy during the exothermic reaction of CH4 with O2.
Explanation:
The correct statement about the reaction CH4 (g) + 2O2 (g) → CO2 (g) + 2H2O(l) ΔH = -890 kJ is that reacting one mole of oxygen (O2) releases 445 kJ of energy. The reaction is exothermic, meaning it releases energy. The ΔH value of -890 kJ means that for every mole of methane (CH4) that reacts, 890 kJ of energy is released. Considering the stoichiometry of the reaction, where 2 moles of oxygen react per mole of methane, half of the total energy release (which is 890 kJ) would be associated with 1 mole of oxygen, thereby releasing 445 kJ.
What term refers to group behavior seen in animals of a similar type?
Answer:
The correct answer is swarm behavior.
Explanation:
Swarming or swarm behavior is a collective behavior demonstrated by entities, mainly the animals of same size that accumulate together, specifically moving in masses or migrating in some direction or milling about the same spot. As a term, swarming is applicable mainly to insects, however, it can also be applied to any other animal or entity, which demonstrates swarm behavior.
What is the total number of electrons in all s orbitals of a neutral atom of phosphorus?
2kl(aq)+cl(g) 2kcl (aq) +l2(g) how many moles of L2 are produced
Match each type of energy with its description or example.
light
heat
chemical
mechanical
electrical
A.
the energy in your food is an example
B.
the kinetic energy of moving water is an example
C.
total kinetic energy of all the atoms that make up a sample of matter
D.
form of energy visible to the human eye
E.
caused by the movement of electrons
Answer:
A: Chemical
B: Mechanical
C: Heat
D: Light
E: Electrical
Explanation:
A: The energy in food is known as chemical energy. Chemical energy is the energy which is stored in the molecular bonds of the compounds (eg. glucose). Hence, when food is digested, many molecules are broken down to their most basic components.
B: Energy that can be used to "do work" is known as mechanical energy. Mechanical energy is energy (usually kinetic and potential energy) which is used to produce a force to an object, and in this conversion, the object then does work (eg. A body of water being used to push a turbine to create electricity).
C: The kinetic energy in atoms/molecules while vibrating is known as heat. Heat energy can be measured as the temperature of a certain substance, but it is actually the sum of all the kinetic energy of every single molecule/atom
D: The energy given off by the sun which allows us to view our surroundings is known as light energy. Light energy enters our eyes and is converted to an electrical impulse that our brain interprets as colour.
E: When electrons move from atom to atom, this is known as electrical energy. This energy is usually found as a property of metals, where they have a "sea" of localised electrons that can allow for the conduction of electricity
What is the main difference between DNA and RNA? DNA contains ribose sugar, and RNA contains deoxyribose sugar instead. DNA contains cytosine, and RNA contains guanine instead. DNA contains deoxyribose sugar, and RNA contains ribose sugar instead. DNA contains adenine, and RNA contains guanine instead.
DNA contains ribose sugar, and RNA contains deoxyribose sugar instead. Therefore, the correct option is option A.
What are DNA and RNA?The complex molecular structures deoxyribonucleic acid (DNA) consequently ribonucleic acid (RNA) regulate all genetic traits of cells, and hence of species. DNA, which makes up the genetic material of all free-living species, is the ultimate life-plan. In addition to being the genetic makeup of some viruses, RNA employs DNA to code out the molecular makeup of proteins made in cells.
The two structures differ chemically in a number of ways. The "backbone" of DNA, or deoxyribose, is a sugar, like the acronym deoxyribonucleic acid suggests. The sugar ribose, which is slightly different, is present in ribonucleic acid (RNA). DNA contains ribose sugar, and RNA contains deoxyribose sugar instead.
Therefore, the correct option is option A.
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