Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or the bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves
Answer:
B) refraction
Explanation:
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The radioisotope phosphorus-32 is used in tracers for measuring phosphorus uptake by plants. The half-life of phosphorus-32 is 14.3 days. How much time is required for the activity of a sample of phosphorus-32 to fall to 7.34 percent of its original value
Answer:
54 days
Explanation:
We have to use the formula;
0.693/t1/2 =2.303/t log Ao/A
Where;
t1/2= half-life of phosphorus-32= 14.3 days
t= time taken for the activity to fall to 7.34% of its original value
Ao=initial activity of phosphorus-32
A= activity of phosphorus-32 after a time t
Note that;
A=0.0734Ao (the activity of the sample decreased to 7.34% of the activity of the original sample)
Substituting values;
0.693/14.3 = 2.303/t log Ao/0.0734Ao
0.693/14.3 = 2.303/t log 1/0.0734
0.693/14.3 = 2.6/t
0.048=2.6/t
t= 2.6/0.048
t= 54 days
Describe how u would separate a mixture of salt , sand and iodine into different components. please help i will give a brainliest for this . PLEASE HELP?
to remove iodine sublime
to remove sand filter
to remove water evaporate
Explanation:
1. put the mixture in a beaker
2.Heat the mixture using a watch glass filled with cold water, the iodine will sublime at the base of the watch glass.
3.Add water to sand and salt. Stir for salt to diffuse in the water
4.Filter sand from the solution using a filter paper
5.evaporate the remaining water to remain with Salt crystals.
What solution usually goes in burette? 1) Acid 2) Base 3) Indicators 4) Water
Answer: the acid
Explanation:
Which refers specifically to a heated solution that holds more dissolved solution than it can hold at a lower temperature? supersaturated undersaturated heterogeneous homogeneous
Answer:
A. Supersaturated
Explanation:
i got it right on edge 2021
The heated solution that holds more dissolved solution than it can hold at a lower temperature is supersaturated solution. Therefore, option A is correct.
What is supersaturated solution ?A solution that contains more solvent than the typical amount that can dissolve at a specific temperature is said to be supersaturated. By introducing a tiny solute crystal known as a seed crystal, the excess dissolved solvent in a super-saturated solution can begin to recrystallize.
A solution that contains more solvent than the typical amount that can dissolve at a specific temperature is said to be supersaturated. A solution is considered supersaturated if it contains more solute than is necessary to saturate it.
A solution that contains more solute than it can hold at a specific temperature is said to be supersaturated. Usually, raising a solution's temperature causes more particles to dissolve, increasing the solute concentration.
Thus, option A is correct.
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In the hydrogenation of oils the catalyst used is:
A. Pt
B. Ni
C. Fe
D. V2O5
Answer:
B
Explanation:
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Gaseous ethane will react with gaseous oxygen to produce gaseous carbon dioxide and gaseous water . Suppose 7.82 g of ethane is mixed with 9.9 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to significant digits
Answer:
4.79 g of water
Explanation:
From the reaction equation;
C2H6(g) + 7/2O2(g) ----> 2CO2(g) + 3H2O(g)
Next we convert the given masses of reactants to moles of reactants.
For ethane; number of moles = mass/molar mass= 7.82g/ 30gmol-1= 0.261 moles
For oxygen; number of moles= 9.9 g/32gmol-1= 0.31 moles
Next we determine the limiting reactant, the limiting reactant yields the least amount of product.
For ethane;
From the reaction equation,
1 mole of ethane yields 3 moles of water
0.261 moles of Ethan yields 0.261 ×3 = 0.783 moles of water
For oxygen;
3.5 moles of oxygen yields 3 moles of water
0.31 moles of oxygen yields 0.31 × 3/3.5 = 0.266 moles of water
Hence oxygen is the limiting reactant.
Mass of water produced = 0.266 moles of water × 18gmol-1 = 4.79 g of water
cid rain can be destructive to both the natural environment and human-made structures. The equation below shows a reaction that occurs that may lead to the formation of acid rain. 3NO2 + H2O Right arrow. 2HNO3 + NO How many moles (precise to the nearest 0.01 mol) of nitric acid are produced from 300.00 mol of nitrogen dioxide?
Answer:
200 moles of nitric acid are produced from 300.00 mol of nitrogen dioxide.
Explanation:
You know that the balanced reaction is:
3 NO₂ + H₂O ⇒ 2 HNO₃ + NO
The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three. Remember that proportionality is a constant relationship or ratio between different magnitudes.
If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:
a ⇒ b
c ⇒ x
So:
[tex]x=\frac{c*b}{a}[/tex]
In this case, the rule of three can be applied in the following way: if 3 moles of NO₂ produce 2 moles of HNO₃ by stoichiometry of the reaction, 300 moles of NO₂ how many moles of HNO₃ do they produce?
[tex]moles of HNO_{3} =\frac{300 moles of NO_{2}*2 moles of HNO_{3}}{3 moles of NO_{2}}[/tex]
moles of HNO₃= 200
200 moles of nitric acid are produced from 300.00 mol of nitrogen dioxide.
Answer:
200.0 mol
Explanation:
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determine the type of the following chemical reaction: Mg(s) + 2HCl(aq)——-> H2(g) + MgCl2(aq) a. single replacement reaction b. decomposition reaction c. combination reaction d. double replacement reaction
Answer:
a. single replacement reaction
Explanation:
Mg(s) + 2HCl(aq)——-> H2(g) + MgCl2(aq)
Mg replaces H, so this is a single replacement reaction.
Why is water so important for life?Why cant other substance made of hydrogen and oxygen like hydrogen peroxide take its place?
Answer:
Reasons water is important
Imagine earth without water. The soil, with no water in it and nothing growing on it, would be lifeless, dead, collapsed into dust, sand, clay or rock.
-Water consumption helps lubricate and cushion your joints, spinal cord, and tissues. This will help you enjoy physical activity and lessen discomfort caused by conditions like arthritis.
-Water is a main component of saliva. Saliva also includes small amounts of electrolytes, mucus, and enzymes. It’s essential for breaking down solid food and keeping your mouth healthy.
Make a list of 5 metals and 5 non metals and their real life application and any additional information about
Answer:
Metals:
Copper: to make cooking utensils such as pots because it has a high heat conductivity.
Aluminium: to make aluminium foil / soda cans because it is malleable
Mercury: fills up thermometers because it can indicate the temperature when it expands. But it is toxic so fewer people are using mercury thermometers now.
Titanium: to make the body of supersonic aircrafts because it is strong and corrosion resistant
Gold: to make jewelry because it is shiny and also corrosion resistant
Non-metals:
Nitrogen: to fill up chip packages because its molecules are unreactive
Helium: to fill up balloons because it is lightweight
Hydrogen: for generating electricity in hydrogen fuel cells. It is environmentally-friendly because it does not produce any greenhouse gas or toxic pollutants.
Fluorine: added in toothpaste for strengthening the teeth. It can also prevent cavities.
Carbon: the graphite in pencils. this is one form of carbon. Other common forms (allotropes) of carbon include diamond and Buckminsterfullerene (buckyball).
TIMED TEST PLS HELP (will give BRAINLIEST) According to some scientists, which is a cause of global warming? PICK ONLY ONE A) decrease of nitrous oxide B) increase in cloud cover C) decrease of methane gas D) increase in carbon dioxide
Answer:
D : increase in carbon dioxide
Answer: the Answer is D, 100% sure
increase in carbon dioxide
Explanation: i did the GED school and got it right
The freezing point of water in degrees Celsius is [ Select ] __________. The freezing point of water in degrees Fahrenheit is [ Select ] __________. The freezing point of water in Kelvin is [ Select ] __________. (Use whole numerals/numbers for all choices — no letters or symbols)
Answer: 0, 32 , 273
Explanation:
The freezing point of water in degree Celsius, Fahrenheit and Kelvin are in the following order; 0 , 32 , 273
What does the following energy
diagram represent?
A. Exothermic reaction
B. Activation energy
C. Endothermic reaction
D. Specific heat capacity
Answer:
Option A) Exothermic Reaction
Explanation:
In exothermic reaction, the energy is released. The reactants are at high energy while the products are at low energy as shown in the graph.
Answer:
A.) Exothermic reaction
Explanation:
I got it correct on founders edtell
10g of sugar is dissolved by water to make 200g of solution of sugar. What is the percent by mass of the solution?
Explanation:
In sugar solution 200 g has sugar 10 g
In sugar solution 100 g has sugar 10/200 × 100
= 5 %w/w
When 12 g of methanol (CH3OH) was treated with excess oxidizing agent (MnO4-), 14 g of formic acid (HCOOH) was obtained. Using the following chemical equation, calculate the percent yield. (The reaction is much more complex than this; please ignore the fact that the charges do not balance.)
3CH3OH + 4MnO4- ----> 3HCOOH + 4MnO2
(a) 100%
(b) 92%
(c) 82%
(d) 70%
(e) 55%
Answer:
(c) 82%
Explanation:
Using the chemical reaction:
3CH₃OH + 4MnO₄⁻ → 3HCOOH + 4MnO₂ + 4e⁻
3 moles of methanol produce 3 moles of formic acid (Reaction 1:1)
To find the percent yield we need to calculate theoretical yield of the reaction when 12g of methanol (Molar mass: 32.04g/mol) are reacting, thus:
12g ₓ (1mol / 32.04g) = 0.3745 moles of methanol are in 12g.
As 1 mole of methanol produce 1 mole of formic acid, assuming a 100% of yield in the reaction (Theoretical yield) moles produced of formic acid are 0.3745 moles.
Using molar mass of formic acid (46.03g/mol), mass of the acid in 0.3745moles are:
0.3745 moles ₓ (46.03g/mol) = 17.2g of formic acid are theoretical yield
Percent yield is calculated as:
(actual yield / Theoretical yield) × 100
As actual yield of the reaction is 14g. Theoretical yield is:
(14g / 17.2g) × 100 = 81.2% ≈ 82%
Right answer is:
(c) 82%The percentage yield of the reaction is 82%
The correct answer to the question is Option C. 82%
We'll begin by writing the balanced equation for the reaction.
3CH₃OH + 4MnO₄⁻ → 3HCOOH + 4MnO₂ + 4e⁻
Molar mass of CH₃OH = 12 + (3×1) + 16 + 1 = 32 g/mol
Mass of CH₃OH from the balanced equation = 3 × 32 = 96 g
Molar mass of HCOOH = 1 + 12 + 16 + 16 + 1 = 46 g/mol
Mass of HCOOH from the balanced equation = 3 × 46 = 138 g
From the balanced equation above,
96 g of CH₃OH reacted to produce 138 g of HCOOH
Next, we shall determine the theoretical yield of HCOOH.From the balanced equation above,
96 g of CH₃OH reacted to produce 138 g of HCOOH.
Therefore,
12 g of CH₃OH will react to produce = (12 × 138)/96 ≈ 17g of HCOOH.
Finally, we shall determine the percentage yield.Actual yield of HCOOH = 14 g
Theoretical yield of HCOOH = 17 g
Percentage yield =?Percentage yield = Actual / Theoretical × 100
Percentage yield = 14/17 × 100
Percentage yield ≈ 82%The correct answer to the question is Option C. 82%
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Q. Give reasons for the following: 1. Graphite has a very high melting point. 2. Graphite is a non-metal but conducts electricity. Answer the question according to the class 9th student.
Explanation:
1.Graphite has a very high melting point because its structure consists of carbon atoms which are held together by strong covalent bonds
2.It has delocalised electrons.
Lawrence experienced a major accident in class. His entire test tube rack with all his chemicals fell and broke. There were chemicals all over the floor. Which would be used to clean his mess? eye wash safety shower sponge chemical spill kit
Answer:
The correct option is;
Chemical spill kit
Explanation:
When cleaning simple chemical spills that do not spread or indirectly put people and property in danger and does not negatively impact o the environment the risk, quantity and likely impact of the spill should be evaluated then with a chemical spill kit which comprises of personal protective clothing, materials that are absorbent, waste bags, broom and dustpan and a waste container can be used absorb, contain the residues, clean the spill and put the collected waste away.
Answer:
Chemical spill kit
Explanation:
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how do we solve a WEAK/STRONG acid
Answer:
Strong acids completely dissociate into their ions in water, while weak acids only partially dissociate. There are only a few (7) strong acids, so many people choose to memorize them. All the other acids are weak.
Explanation:
Weak acids. Explaining the term "weak acid" A weak acid is one which doesn't ionise fully when it is dissolved in water. Ethanoic acid is a typical weak acid. It reacts with water to produce hydroxonium ions and ethanoate ions, but the back reaction is more successful than the forward one.
A strong acid is an acid which dissociates completely in water. That is, all the acid molecules break up into ions and solvate (attach) to water molecules. Therefore, the concentration of hydronium ions in a strong acid solution is equal to the concentration of the acid.
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How much water should be added to 12 ml of alcohol to obtain 12% alcohol solution?
Answer:
88 mL of water.
Explanation:
Data obtained from the question include the following:
Volume of alcohol = 12 mL
Percentage of alcohol = 12%
Volume of water =..?
We can thus, obtain the volume of water needed to make 12% of the alcohol solution as follow:
Percentage of the solution = 100%
Percentage of alcohol = 12%
Percentage of water =?
Percentage of water = percentage of solution – percentage of alcohol
Percentage of water = 100 – 12
Percentage of water = 88%
Since 12% of alcohol is equivalent to 12 mL of alcohol, therefore 88% of water will also be equivalent to 88 mL.
Therefore, 88 mL of water is needed to make 12% of alcohol.
someone help PLSSSS. i’ve asked this question like 3 times already Determine the number of lone pair electrons on each H in NH3. Z of N= 7, H=1 A. 0 B. 3 C. 1 D. 2
Answer:
The answer is option B.
3.
Hope this helps you
What is the percentage of OH- in Ca(OH)2
By weight the hydroxides are 45.9% of the weight
The mass percentage of the OH⁻ in the compound Ca(OH)₂ is 45.94 %.
What is the mass percentage?The percentage of any element or group of atoms in a given compound is the number of parts by mass of that element or group of atoms present in 100 parts by mass of the given compound.
The percentage of an element can be calculated in 2 steps:
First, calculate the molar mass of the compound by the addition of the atomic masses of the atoms. Then, the percentage of the elements by dividing the total mass of the element or or group of atoms by the molar mass of the compound multiplied by 100.
Given, the molecular formula of the given compound is Ca(OH)₂. The atomic mass of calcium, hydrogen, and oxygen is 40g, 1 g, and 16 respectively.
The molecular mass of the Ca(OH)₂ = 74 g/mol
The mass of OH in Ca(OH)₂ = 34 g
The mass percentage of the OH⁻ = (34/74) × 100 = 45.94 %
Therefore, the mass percentage of the OH in Ca(OH)₂ is equal to 45.94%.
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Why is the mole important? Group of answer choices It can be applied to any type of object: molecules, atoms, ions, etc. It gives us a convenient way to express large numbers. It is useful when converting between grams and atoms or molecules. All of the above.
Answer: the mole
Explanation:
The mole is the unit of amount in Chemistry.
It provides a bridge between the atom and the macroscopic amounts of material that we work with in the laboratory.
news coverage and tend to _ drug use?
a)discourage B)glamorize
C)glamorize
Answer:
glamorize
Explanation:
There are many stories about celebrities being on drugs, and the media seems to deliver the stories in a way that acts as drugs are beneficial and further glamorizes them.
News coverage tends to glamorize drug use.
How does social media influence pills?An examination performed by the national middle on addiction and Substance Abuse at Columbia college discovered that young adults who frequently use popular social media outlets have been more likely to drink, use pills, and buy tobacco than adolescents who both did no longer use social media or used it less regularly.
Does media insurance have an effect on the spread of drug addiction?The effects display that the media impact on the human populace cannot exchange the stabilities of equilibria however can affect the number of drug addicts. Sensitivity analyses are performed to search for powerful control measures for drug treatment.
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What is the mass of 15% of solution of lime that is formed by dissolving 30g of calcium hydroxide in water?
Answer:
200 grams is the mass of 15% of the solution of lime that is formed by dissolving 30g of calcium hydroxide in water.
Explanation:
Mass of solution = M
Mass percentage of the solution of lime = 15%
Mass of lime or calcium hydroxide = m = 30 g
The Formula of mass percentage is given as :
[tex]m/m\%=\frac{m}{M}\times 100[/tex]
On substituting the values in ab above formula :
[tex]15\%=\frac{30 g}{M}\times 100[/tex]
[tex]M=\frac{30 g}{15}\times 100=200 g[/tex]
200 grams is the mass of 15% of the solution of lime that is formed by dissolving 30g of calcium hydroxide in water.
Sulphuric acid, also called ‘king of chemicals' has the formula H2SO4. Its appearance is different from that of hydrogen and sulphur. Give two other reasons why sulphuric acid is a compound and not a mixture.
Explanation:
Before proceeding to answering the question, we have t understand what we mean by both mixture and compound.
A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in the form of solutions, suspensions and colloids.
A compound on the other hand is a chemical substance composed of many identical molecules composed of atoms from more than one element held together by chemical bonds.
The two other reason why H2SO4 is a compound and not a mixture are;
1) The components which are Hydrogen, Sulphur and Oxygen cannot be separated by physical means.
2) It has a constant melting and boiling point.
what’s the answer ?????
option A is the correct one
It represents Mp orBp of a substance at a specific pressure
3 point different between fundamental units and derived units
Answer:
Fundamental Units:
1) Fundamental units also called base units are used to describe base quantities
2) They cannot be expressed in terms of derived units.
3) Examples : Meter, Ampere, Second etc.
Derived Units:
1) Derived units are used to describe derived quantities.
2) They can be expressed in terms of fundamental units.
3) Examples: Newton, Joule, Hertz, Pascal etc.
Answer:
3diferences
Explanation:
fundamental are independent but derived are dependent
there are 7fundamental units but there are many derived units from fundamental.
meter, second, kilogram, etc are examples of fundamental but m/s^2, newton, joule, etc are derived units
An element of Group Il loses two electrons in the process of a chemical combination. What is its ionic charge?
A. +2
B. -2
Answer:
A. +2
Explanation:
When neutral atom loses electrons, number protons(+) becomes more than number of electrons(-), so charge of ion is positive.
he Lewis structure for CO molecule contains Group of answer choices one double bond, one single bond, and twelve nonbonding electrons two double bonds and eight nonbonding electrons one triple bond and four nonbonding electrons two single bonds and twelve nonbonding electrons
Answer:
One triple bond and four non bonding electrons
Explanation:
In considering the lewis structure of carbon monoxide, we must remember that the molecule contains a total of ten valence electrons. Four are the valence electrons that are present on the valence shell of carbon while six are the valence electrons on oxygen. Some of these valence electrons participate in bonding in the CO molecule.
Out of the six valence electrons on oxygen, two valence electrons participate in bonding with carbon while the other four electrons remain localized on the oxygen atom as two lone pairs of electrons.
Hence there are four nonbonding electrons in the lewis structure of CO as well as one triple bond.
An aluminum kettle weights 1.05 kg and has a heat capacity of 0.9211 J over grams Celsius how much heat is required to increase the temperature of the scuttle from 23.0 Celsius to 90
Answer:
64799.4 J
Explanation:
The following data were obtained from the question:
Mass (M) = 1.05 kg = 1.05 x 1000 = 1050g
Specific heat capacity (C) = 0.9211 J/g°C
Initial temperature (T1) = 23°C
Final temperature (T2) = 90°C
Change in temperature (ΔT) = T2 – T1 =
90°C – 23°C = 67°C
Heat required (Q) =....?
The heat required to increase the temperature of the kettle can b obtain as follow:
Q = MCΔT
Q = 1050 x 0.9211 x 67
Q = 64799.4 J
Therefore, 64799.4 J of heat is required to increase th temperature of the kettle from 23°C to 90°C.