Answer:
=zero degrease, 1 atm)? so the volume of an ideal gas is 22.l/mol at STP this, 22l.4Lis probably the most remembered and least useful number in chemistry
Answer:
B) 22.4
Explanation:
WILL MARK BRAINLIEST IF CORRECT
Answer:
3 - a heterogeneous mixture
4- Sweet tea is an homogeneous mixture
Answer:
Explanation:
6. d
7. b
8. c
22.5 ml of a 0.200 m HBr solution was added to a 50.00 ml sample of 0.250 m sodium benzoate (NaC7H5O2). Calculate the pH. Benzoic acid has a Ka 6.30 x 10-5.
In this problem, we need to find the pH of a buffer (pH = 4.45) that is produced by the reaction of strong acids as HBr that reacts with weak bases as NaC₇H₅O₂ producing its weak acid and a salt, as follows:
HBr + NaC₇H₅O₂ → HC₇H₅O₂ + NaBr
If in the reaction, the limiting reactant is the strong acid, we will produce a buffer (The aqueous mixture of a weak acid and its strong base).
Using Henderson-Hasselbalch equation, we can find the pH of this buffer:
[tex]pH = pKa + log \frac{[NaC_7H_5O_2]}{[HC_7H_5O_2]}[/tex]
Where:
pKa is -log Ka = 4.20
[] could be taken as the moles of each species
After the reaction, the moles of HBr = Moles of HC₇H₅O₂ and the remaining moles of NaC₇H₅O₂ = Initial moles of NaC₇H₅O₂ - Moles of HBr.
Moles HBr:
22.5mL = 0.0225L * (0.200mol/L) = 4.5x10⁻³ moles HBr
Moles NaC₇H₅O₂:
50.0mL = 0.0500L * (0.250mol/L) = 0.0125 moles NaC₇H₅O₂
That means the moles after the reaction of the species of the buffer are:
Moles HC₇H₅O₂ = Moles HBr = 4.5x10⁻³ moles
Moles NaC₇H₅O₂ = 0.0125 moles - 4.5x10⁻³ moles = 8.0x10⁻³ moles
Replacing in H-H equation:
[tex]pH = 4.20+ log \frac{[8.0x10^{-3}]}{[4.5x10^{-3}]}[/tex]
pH = 4.45
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how does activation energy affect the process of a reaction
Answer:
The activation energy increases how quickly the reaction will progress.
Explanation:
The activation energy of a chemical reaction is intimately linked to its rate. Particularly, the greater the activation energy, the slower the chemical reaction will be. The reason is: molecules can only finish the reaction as soon as they have reached the peak of the activation energy barrier. Many reactions possess such huge activation energies that they practically don't advance at all without an input of energy.
The activation energy of a particular reaction determines the rate at which it will proceed. The higher the activation energy, the slower the chemical reaction will be.
Froming a hypothesis is the first step of the scientific methhod true or false
Answer:
The first step in the Scientific Method is to make objective observations. These observations are based on specific events that have already happened and can be verified by others as true or false. Step 2. Form a hypothesis.
Answer:
False
Explanation:
The first step of the scientific method is to make an observation.
What types of mixtures are these?
Explanation:
Homogeneous Mixture:-
A cup of tea and sugarFood coloring dissolved in waterHeterogeneous Mixture:-
Peanuts and almonds mixed together in a bowlA bucket full of sand and gravel2. School bus accidents are very rare, possibly because they are so easy to see.
School buses have been around since 1915, but the official color of bright
yellow wasn't used until 1939. Would grey school buses get in more accidents?
Help plz!!!
Answer:
Grey school buses would likely get in more accidents because other drivers are expecting a yellow bus to make frequent stops and the lights and stop sign are noticeable on a brighter color.
Explanation:
yellow buses are easier to see in fog than a grey bus
Water has __________ than other liquids such as ethanol , reflecting its capacity to absorb large amounts of heat. View Available Hint(s)for Part A lower specific heat a lower heat of vaporization a higher boiling point a lower capacity for forming hydrogen bonds less surface tension
Answer:
a high boiling point
Explanation:
Water has a high boiling point because it is held together by stronger molecular forces compared to ethanol
Silica (also known as silicon dioxide) reacts with hydrofluoric acid to produce silicon tetrafluoride and water vapor.
a) Write the balanced chemical equation for the reaction
b) 12.5 g of silicon dioxide is reacted with a 24.6 g of hydrofluoric acid. What is the theoretical yield of water vapor?
c) If the actual yield of water vapor is 2.50 g, what is the percentage yield of the reaction?
The problem is solved by balancing the reaction equation as shown below. The stoichiometry of the reaction is now applied in solving the question.
The balanced reaction equation is:
SiO2 + 6HF → H2[SiF6] + 2H2O
Using stoichiometry
The amount of silicon dioxide reacted = 12.5 g/60.08 g/mol = 0.21 mole
1 mole SiO2 yields 2 moles of H2O
0.21 mole of SiO2 yields 0.21 * 2/1 = 0.42 moles of H2O
The amount of HF reacted = 24.6 g/20.01 g/mol = 1.23 moles of HF
6 moles of HF yield 2 mole of H2O
1.23 moles of HF yields 2 * 1.23/6 = 0.41 moles of H2O
Hence HF is the limiting reactant.
Theoretical yield of H2O = 0.41 moles of H2O * 18 g/mol = 7.38 g
The percentage yield of the water is = actual yield/theoretical yield * 100
Hence;
% yield = 2.50 g/7.38 g * 100 = 33.9%
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prepare a dialogue between two friends about development of society .
Answer:
Pls pls pls mark brainliest
Answer: Freezing point depression
Explanation:
freezing point depression is a phenomenon that describes why adding a solute or solvent results in the lowering of the freezing point of the solvent
The volume of a gas was 48 mL when the temperature was 159.6 ºC. If the temperature was initially 4.9 ºC, and there was no change in the pressure, what was the initial volume of the gas?
According to Charles law
[tex]\boxed{\sf \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}}[/tex]
[tex]\\ \sf\longmapsto \dfrac{48}{159.6}=\dfrac{V_2}{4.9}[/tex]
[tex]\\ \sf\longmapsto V_2=\dfrac{48\times 4.9}{159.6}[/tex]
[tex]\\ \sf\longmapsto V_2=\dfrac{235.2}{159.6}[/tex]
[tex]\\ \sf\longmapsto V_2=1.4mL[/tex]
The law of conservation of energy states that A: energy is always created and destroyed B: energy cannot be created or destroyed C: energy is unable to change forms D: energy should be saved as often as possible
Answer:
B
Explanation:
This is the First Law of Thermodynamics which states that energy cannot be created or destroyed.
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How many neutrons are present in 4.4 gram of Co2
Explanation:
hope it will help you Mark me as a brilliant
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the first attempt to classify the elements was made by newlands true or false
Answer:
True. An English scientist by the name of John Newlands tried to classify the elements in a unique manner. He first started by arranging all the elements in a ascending order according to their atomic weights.
Which is the electron configuration for lithium?
1s2
2s3
1s22s1
1s12s2
Answer:
1s2, 2s1
Explanation:
Lithium is the first element in the 2nd row of elements meaning its 1s orbital is completely filled and 1 electron is in the 2s orbital.
Answer:
the answer is C
Explanation:
26. Calculate the mass of hydrogen formed when 25 grams of aluminum reacts with excess hydrochloride acid. 2AI + 6HCl →l Al2Cl6 + 3H2
Answer:
2.76 gram
Explanation:
2AI + 6HCl → 2AlCl3 + 3H2
get the mol of aluminum => n = m / M = 25 / 27 = 0.925 (mol)get the ratio mol of Hydro => nH2 = 0.925 * 3 / 2 = 1.38 (mol)get weight of hydro mH2 = n x M = 1.38 x 2 = 2.76 (gram)Answer
Al +2 HCl - AlCl2 + H2
Cellular respiration occur within ______ of a cell.
Answer:
The mitochondria
Explanation:
Its where cellular respiration occurs
Which of the following is the best definition of a physical property?
A. Tearing paper in half.
B. Something that can be observed or measured while changing the identity of the substance.
C. The ability of something to undergo a change or reaction.
D. Something that can be observed or measured without changing the identity of the substance.
Answer:
D.Something that can be observed or measured without changing the identity of the substance.
7. What measures are applicable in the context of Nepal to push energy crisis further. Describe any three points clearly.
Answer:
which energy?........
Explanation:
..........................
........
....
1. what is hard water.
2. Mention four sources of water.
3. write down the chemical formula of water.
4. What is purification of water.
5. Mention two importance of purification of water.
6. Mention 4 method used ot purify water. 7. Mention 4 impurities found in water.
8. Explain the term contaminated of water.
9. State two physical properties of water. 10. mention the names of of the elements that causes hardness in water.
Answer:
Oh man, the questions are much
Explanation:
1. Hard water is water what has high mineral content. (I can't go into details )
2. River, reservoir, Lake, groundwater, rain
3. H2O
4. POW is the process of removing undesirable chemicals, biological contaminants, suspended solids and gases from water.
5. Reduces amount of chlorine, soil residue, and organic and inorganic substances. Helps in improving the taste. Smell and visual appearance of water.
6. Boiling, filtration, distillation, and chlorination
7. Dust, dirt, harmful chemicals, biological contaminants, radiological contaminants
8. It is the contamination of water bodies, usually as a result of human activities, in such a manner that negatively affects it legitimate uses.
9. Colorless, turbidity, taste And odor.
10. Hardness of water is caused by compounds of calcium and magnesium, and by a variety of other metals.
What is a base?
A. A substance that increases the concentration of oxygen in
solution
B. A substance that increases the concentration of OH ions in
solution
C. A substance that increases the concentration of H+ ions when dissolved
D. A substance that contributes chloride ions to the solution
Answer:
A base releases OH~ in a solution, so the answer is B
How IS energy related to the change of state represented
by the model?
Atoms gain energy as a solid changes to a gas.
Atoms gain energy as a liquid changes to a gas.
Atoms lose energy as a solid changes to a gas.
Atoms lose energy as a liquid changes to a gas.
Answer:
Gain energy as a liquid changes to a gas
Explanation:
get further apart= more kinetic energy
liquid at beginning as not uniform but quite close together and takes shape of container
The answer is...Liquid into gas.
My Explanation:
Stated in the model, The atoms aren't that active but can still slider past each other; meaning, this is a liquid. As it shifts into a gas, which is when atoms pick up energy and move around more freely/actively, the definition of the following is "Vaporization".
So the answer is: B, or in other words, "Atoms gain energy as a liquid turns into a gas.
Which of the following would increase the pressure of a gas in a container?
A. Decreasing the kinetic energy of the gas
B. Increasing the temperature of the gas
C. Decreasing the number of gas particles
D. Increasing the volume of the container
The only option that would increase the pressure of a gas in a container is B. Increasing the temperature of the gas. Option B
To understand which factor would increase the pressure of a gas in a container, we need to consider the relationship between pressure and various variables in the ideal gas law and the kinetic theory of gases.
The ideal gas law states that pressure (P) is directly proportional to the number of gas particles (n), the temperature (T), and inversely proportional to the volume (V) of the container. Mathematically, it can be expressed as:
PV = nRT
where R is the ideal gas constant.
Based on this equation, we can analyze the options given:
A. Decreasing the kinetic energy of the gas: According to the ideal gas law, temperature is directly proportional to pressure. Therefore, decreasing the kinetic energy (which is related to temperature) would decrease the pressure, not increase it.
B. Increasing the temperature of the gas: As mentioned above, temperature is directly proportional to pressure. Increasing the temperature of the gas would increase its kinetic energy, resulting in more frequent and energetic collisions with the container walls, thus increasing the pressure.
C. Decreasing the number of gas particles: According to the ideal gas law, the number of gas particles (n) is directly proportional to pressure. Therefore, decreasing the number of gas particles would decrease the pressure, not increase it.
D. Increasing the volume of the container: According to the ideal gas law, volume (V) is inversely proportional to pressure. Increasing the volume of the container would decrease the pressure, not increase it.
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Modern periodic table is based upon atomic number. Explain what does the modern periodic table states about the atomic numbers ?
Answer:
Explanation:Elements of the periodic table are arranged in order of increasing atomic number. The periodic law states “When elements are arranged in order of increasing atomic number, there is a periodic repetition of their chemical and physical properties.”
The solubility of solids______ when the temperature is increased.
A. increases
B. decreases
C. does not change
Which of the following describes metallic character on the periodic table?
A. It increases as you move right to left within a period and down a group on the periodic table.
B. It increases as you move left to right within a period and down a group on the periodic table.
C. It increases as you move right to left within a period and up a group on the periodic table.
D. It increases as you move left to right within a period and up a group on the periodic table.
Mark for review (Will be highlighted on the review nane)
help
Answer:
Option A.
Explanation:
If you picture the Periodic Table in your head...
you'd see that the Metals are located at the left hand part of the periodic table and their Metallic Character Increases as you go down the group.
So if you travel from the right, towards the left...You'd come across your Metals.
In order words... Option A is your answer.
describe any four factors that bring out a chemical change.
Answer:
Physical state of reactants
Temperature
Concentration of reactants
Presence of a catalyst
Explanation:
The larger the surface area of a reactant, the faster the rate of the reaction. If the reactant is in powdered form, the reaction takes place faster than when the reactant is in solid or block form. This is due to the fact that the latter has larger surface area
Increase in temperature causes reactant molecules to gain kinetic energy thus increasing the rate if reaction
what does porous mean
Answer:
porous = allowing liquid or air to pass through slowly
I hope it's helpful
Answer:
It is a rock or or other materials, having minutes interstices through which liquid or air may pass.
PLEASE HELP URGENT!!!! 20 POINTS!!!!!
Identify the most common graph types, and explain what each is used for.
Explanation:
Bar Graph.Segmented Bar Graph.Column Graph. Whiskers Graph (also called a Box Plot)Frequency Graph (Frequency Table)Cumulative Frequency Table.Frequency Polygon.Histogram.BAR GRAPH
The bar graph is used to compare the items between different groups over time, bar graphs are used to measure the changes over a period of time, when the changes are larger, a bar graph is the best option to represent the data.
SEGMENTED BAR GRAPH
A segmented bar graph is used to compare two categories within a data set, the whole bar represents all the data within one category. Then, each bar is separated into parts (segments) that show the percentage of each part in the second category.
COLUMN GRAPH
A column graph summarizes categorical data by presenting parallel vertical bars with a height (and hence area) proportionate to specific quantities of data for each category, this type of graph can be useful in comparing two or more distributions of nominal- or ordinal-level data.
WHISKERS GRAPH
A box and whisker plot is a way of summarizing
a set of data measured on an interval scale, it is often used in explanatory data analysis, this type of graph is used to show the shape of the distribution, its central value, and its variability.
FREQUENCY GRAPH
Frequency tables, pie charts, and bar charts can be used to display the distribution of a single categorical variable,these displays show all possible values of the variable along with either the frequency (count) or relative frequency (percentage).
CUMULATIVE FREQUENCY GRAPH
Cumulative frequency is used to determine the number of observations that lie above (or below) a particular value in a data set, the cumulative frequency is calculated by adding each frequency from a frequency distribution table to the sum of its predecessors.
FREQUENCY POLYGON
A frequency polygon is a graphical form of representation of data, it is used to depict the shape of the data and to depict trends, It is usually drawn with the help of a histogram but can be drawn without it as well. Frequency polygons are a graphical device for understanding the shapes of distributions.
HISTOGRAM
A histogram is used to summarize discrete or continuous data, in other words, it provides a visual interpretation of numerical data by showing the number of data points that fall within a specified range of values (called “bins”). It is similar to a vertical bar graph.
Energy in the amount of 420 J is added to a 35 g sample of water at a temperature of 10°C. What is the final temperature of the water?
The final temperature of the water, T2 = 38.57°C
Temperature can be defined as a measure of the degree of hotness or coldness of a physical object (body). Thus, it is measured with a thermometer and its units are degree Celsius (°C), Fahrenheit (°F) and Kelvin (°K).
A calorie refers to the amount of heat required to raise the temperature of a gram of water by one (1) degree Celsius (1°C).
Given the following data:
Quantity of energy = 420JMass = 35 gramsInitial temperature, T1 = 10°CThe specific heat capacity of water is 4.2 J/g°C.
To find the final temperature of the water (T2):
Mathematically, the quantity of energy (heat capacity) is given by the formula;
[tex]Q = mcdt[/tex]
Where;
Q represents the heat capacity or quantity of heat.M represents the mass of an object.C represents the specific heat capacity of water.dt represents the change in temperature.Substituting the values into the formula, we have;
[tex]420 = 3.5 \; * \; 4.2 \; * \; dt[/tex]
[tex]420 = 14.7 \; * \; dt\\\\dt = \frac{420}{14.7}[/tex]
Change in temperature, dt = 28.57°C
Next, we would solve for the final temperature by using this formula;
[tex]dt = T2 - T1[/tex]
[tex]28.57 = T_{2} - 10\\\\T_{2} = 28.57 \; + \; 10\\\\T_{2} = 38.57[/tex]
Final temperature, T2 = 38.57°C
Therefore, the final temperature of the water, T2 is equal to 38.57°C
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