An educated guess which explains observations is called:
a a law
b an experiment
c a hypothesis
d a variable
Answer:
c. a hypothesis is the correct answer
Explanation:
Considering the temperature vs. time graph below, how does the temperature at the beginning of a change of state
compare with the temperature at the end of the change?
Temperature vs. Time
140
120
100
80
60
Time (min) →
4
The temperature is always lower.
The temperature is always the same.
The temperature is usually lower.
The temperature is usually higher.
Temperature (°C)
The temperature is always the same.
How Temperature manifests in objects ?Assume we have something in solid phase. As we increase the temperature, the particles on the solid increase their kinetic energy, thus, the particles move more.
This causes that the volume of the object increases (for example when we heat up a metal and it dilates) and this keeps happening until we reach a critical point, when we are near a change of phase.
At this point the energy given is not used to increase the temperature of the object, but is used to "break" bonds in such a way that the particles are more free than before.
When all these bonds are "broken" the change of phase is completed, and in the case of the solid, we go from solid phase to liquid phase.
So, the temperature is always the same at the beginning of a change of state compare with the temperature at the end of the change
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Specialized periodicals in which scientists publish the results of their works are called
Specialized periodicals in which scientists publish the results of their works are called scientific journals.
In educational publishing, a scientific journal is a periodical book intended to similarly the progress of technology, typically by way of reporting new studies.
Journal articles may include original research, re-analyses of studies, opinions of literature in a selected place, proposals of new but untested theories, or opinion pieces.
These scientific journals include the following.
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10.00 g of LiCl is dissolved in water to make 1.00 L of "Solution A". Then, 100 mL
of solution A were diluted to a volume of 500 mL of "Solution B". What is the
molarity of solution B? (Report your answer to four places past the decimal point.
Moodle is looking for a number only, no units.)
0.47 M is the molarity of solution B if 10.00 g of LiCl is dissolved in water to make 1.00 L of "Solution A".
Define the molarity of a solution.Molarity (M) is the amount of a substance in a certain volume of solution. Molarity is defined as the moles of a solute per litres of a solution. Molarity is also known as the molar concentration of a solution.
[tex]Molality = \frac{Moles \;solute}{Solvent \;in \;kg}[/tex]
Moles of LiCl
[tex]Moles = \frac{mass}{molar \;mass}[/tex]
[tex]Moles = \frac{10.00 g}{42.394 g/mol}[/tex]
Moles = 0.2358824362
[tex]Molality = \frac{0.2358824362}{0.5 L}[/tex]
Molarity = 0.4717648724 M =0.47 M
Hence, 0.47 M is the molarity of solution B.
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Find the ratio of the volume divided by the
temperature for the first data pair. Use significant
figures.
V/T=0.72/276= 0.002 ✓
COMPLETE
Now do the same computation for all six pairs of
values. What is the average of all six fractions V/
T?
From the pair of values given, the ratio of the volume to the temperature for the first data pair is, 0.0026 cm³/K
What is a Ratio?A ratio is a comparison between two quantities showing how much one quantity differs from another.
From the data given, the first data pair is as follows ;
Temperature = 276 KVolume = 0.72 cm³Ratio of volume to temperature = volume / temperature
Ratio = 0.72 / 276
Ratio = 0.002608 cm³/K
The significant figure's rule for division is the least number of significant figures used in the operation.
The least significant figure of the values given is 2.
Therefore, the ratio of the volume to the temperature for the first data pair is 0.0026 cm³/K
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Answer:
0.0026
Explanation:
edge 2022 it's the same answer for both parts
Heat _____.
can only betransferredif molecules are touching
is always created by friction
is a type of potential energy
is the same as temperature
Only certified electricians are allowed to work on facility electrical system?
When producing a soluble salt in a reaction between an acid and an alkali, how can you prepare dry solid crystals from the solutions
1)evaporation/crystallization
2)filtration
3)condensation
4)nuetralisation
Explanation:
Making a salt from an alkali
If you are using an alkali - which is a soluble base - then you need to add just enough acid to make a neutral solution (check a small sample with universal indicator paper).
Warm the salt solution to evaporate the water. You get larger crystals if you evaporate the water slowly.
Ascorbic acid (vitamin C) has the molecular formula C H₂O (molar mass = 176.12 g/mol) The recommended daily allowance of
ascorbic acid in the diet of a human adult is 0.045 g. How many molecules of ascorbic acid is this?
Select one:
1.54 x 10^20molecules
2.56 x 10^-4molecules
2.71x 10^22 molecules
4.77 x 10^24 molecules
Answer:
1.54 × 10²⁰ molecules
Explanation:
Dividing the mass by the molar mass, we get the number of moles to be (0.045)/(176.12), which is about 0.0002555 mol.
Avogadro's law states that there are 6.022 × 10²³ molecules in one mole of a substance, so the answer is
(0.0002555)(6.022 × 10²³), which is 1.54 × 10²⁰ molecules.
Justify that the shielding effect of an atom remain constant in a period but atomic size gradually gets smaller (chemistry)
Atomic size decreases across a period because but the positive charge of the nucleus gets increases across a period.
What is the shielding effect?The shielding effect is the shielding from the pulling force of the positively-charged nucleus given to. the outermost shell electrons by the inner electrons.
Since the shielding effect remains constant across a group but the positive charge of the nucleus gets bigger, atomic size decreases across a period.
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the difference between cow stomach and human stomach
The primary distinction between the digestive systems of cows and humans is that the former uses a foregut fermenter while the latter uses a straightforward monogastric digestion. The types of teeth, mouths, stomachs, guts, and digestive enzymes released by the gut also vary between the two digestive systems. Cows and humans have different digestive systems because they have evolved two different sorts of dietary patterns based on their capacities. The primary distinctions between the digestive systems of cows and humans are in the types of teeth, mouths, stomachs, and intestines, as well as the enzymes released.
Answer:
The main difference between cow and human digestive system is that cow exhibits a foregut fermenter digestion whereas human exhibits a simple monogastric digestion. Both digestive systems also differ by the type of teeth, mouth, stomach, gut, and digestive enzymes secreted by the gut.
Explanation:
how do we compare the PH of a weak acid and a strong acid of identical concentration and draw a conclusion about the concentration of hydrogen ions?
Answer:
This means that the pH values of strong acids are lower than that of weak acids, which explains why the rate of reaction of strong acids with substances (such as metals, metal carbonates etc) is higher than that of weak acids.
Explanation:
welcome
Which shows an isomer of the molecule below?
Answer: C
Explanation:
A) There is 1 fewer hydrogen atom.
B) There are 2 fewer carbon atoms.
D) There is 1 extra hydrogen atom.
The ideal gas law only approximates the behaviour of real gases. The conditions
under which the ideal gas law is MOST accurate are
a. Low pressure and high temperature
b. Low pressure and low temperature
c. High pressure and high temperature
d. High pressure and low temperature
4
25.0 mL of a 0.625 M solution are diluted to a total volume of 100 mL. What is
the molarity of the new solution? (Report your answer to three places past the
decimal point. Moodle is looking for a number only, no units.)
Answer:
.156 M
Explanation:
diluting 25 to 100 cuts the M to 1/4 of the original
1/4 * .625 = .15625
which trends increase to the lower left: metallic character, non-metallic character, atomic radius, ionization energy, electronegativity?
Metallic character increase to the lower left of the periodic table.
What is periodicity?Periodicity is the regular variation in the properties of an element across a period and down a group.
The following properties of elements show periodicity:
metallic character,non-metallic character,atomic radius, ionization energy,electronegativityThe properties that shows increasing trend to The lower left of the periodic table is metallic character.
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6. How many grams are present in 13.2 moles of O₂?
Answer:
422.3868 Grams
Explanation:
13.2 (MOLES) * 31.999 (Dioxygen's Molar Mass) = 422.3868 (Grams Present)
How many milliliters of a 0.8 solution of citric acid would be needed to react with 15 g of baking soda? Show your work.
225 milliliters of a 0.8 solution of citric acid would be needed to react with 15 g of baking soda.
How to calculate volume?The volume of a substance can be calculated using the following formula:
molarity = no of moles ÷ volume
no of moles of baking soda (NaHCO3) = mass ÷ molar mass
Molar mass of baking soda = 84.007g/mol
no of moles = 15g ÷ 84.007g/mol = 0.18mol
0.8 = 0.18/volume
volume = 0.23L equivalent to 225mL
Therefore, 225 milliliters of a 0.8 solution of citric acid would be needed to react with 15 g of baking soda.
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225 millilitres of a 0.8 solution of citric acid would be needed to react with 15 g of baking soda.
Define molarity of a solution.Molarity (M) is the amount of a substance in a certain volume of solution. Molarity is defined as the moles of a solute per litres of a solution. Molarity is also known as the molar concentration of a solution.
[tex]Molality = \frac{Moles \;solute}{Volume of solution in litre}[/tex]
[tex]Moles of baking soda (NaHCO_3) =\frac{mass}{molar \;mass}[/tex]
Molar mass of baking soda = 84.007g/mol
[tex]Moles of baking soda (NaHCO_3) =\frac{15g}{84.007g/mol}[/tex]
[tex]Moles of baking soda (NaHCO_3) = 0.18mol[/tex]
Now, calculating volume with the molarity formula:
Molality = [tex]\frac{Moles \;solute}{Volume \;of \;solution \;in \;litre}[/tex]
0.8 = [tex]\frac{0.18 }{Volume \;of \;solution \;in \;litre}[/tex]
Volume = 0.23L equivalent to 225mL
Therefore, 225 milliliters of a 0.8 solution of citric acid would be needed to react with 15 g of baking soda.
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7.0 mol Mn reacts with 5.0 mol
O2 according to the equation below:
2Mn + O₂ → 2MnO
How many moles of MnO form from
5.0 mol Mn?
[?] mol MnO
Round your answer to the tenths place.
5 moles of MnO form from 5.0 mol Mn. Details about stoichiometry can be found below.
How to calculate number of moles?The number of moles of a substance can be calculated stoichiometrically as follows:
According to this question, the following chemical equation is given as follows:
2Mn + O₂ → 2MnO
2 moles of Mn forms 2 moles of MnO
Hence, 5 moles of Mn will form 5 × 2/2 = 5 moles of MnO.
Therefore, 5 moles of MnO form from 5.0 mol Mn.
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Answer: 10.0
Explanation: i took the test
IB Chemistry SL Question - Empirical/Molecular formulae
A 4.406g sample of a compound containing only C, H and O was burnt in excess oxygen. 8.802g of CO2 and 3.604g of H2O were produced.
i) Determine the empirical formula of the compound (section 6 of the data booklet)
ii) Determine the molecular formula of this compound if its molar mass is 88.12gmol-1
Answer:
(i)
Explanation:
is it right
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The density of water is 1 g/cm3. brent used the following method to convert 1 g/cm3 to kg/m3.
(1 kg = 1,000 g and 1 m = 100 cm)
what is the error in brent's conversion method?
a - 1 kg should be written as 1 g.
b - (1 m)3 should be written as (1 cm)3.
c - 1,000 kg should be written as 1,000 g.
d - (100 cm)3 should be written as (100 m)3.
Answer:
a) The wrong denominator for the equivalent fraction of kilograms to grams
b) The use of the scale factor of length rather than the scale factor of volume for the equivalent fraction of cubic centimeters to cubic meters
c) The arrival at the correct 1000 kg/m³ rather than 0.1 g/m³ based on the expression on the left of the equation
The density of water = 1 g/cm³
The given equation is presented as follows;
1 g/cm³ × 1 kg/(1000 kg) × 100 cm³/(1 m³) = 1000 kg/m³
The error in the conversion method are;
a) The conversion, 1 kg/(1,000 kg) has an error, the correct conversion is (1 kg)/1,000 g)
b) The volume conversion error, 100 cm³/(1 m³), the correct volume conversion is (100 cm)³/(1 m³) = 1,000,000 cm³/(1 m³)
c) The right of the equal to sign error; using the left side expression only, the (wrong) answer is 0.1 g/m³
The correct equation is presented as follows;
1 g/cm³ × 1 kg/(1000 g) × 1,000,000 cm³/(1 m³) = 1000 kg/m³
Explanation: hope this help.
Answer:
c - 1,000 kg should be written as 1,000 g.
Explanation:
got it correct on the test.
How many moles of oxygen are in 4.4 moles of Al(NO3)3 ?
Answer: 40. mol (to 2 sf)
Explanation:
Since there are 9 oxygen atoms in every molecule of aluminum nitrate, this means that there are 9 moles of oxygen atoms in each mole of aluminum nitrate.
So, in 4.4 moles, there are 9(4.4) = 40. mol (to 2 sf)
What is the change in freezing
point, ATf, when the 0.195 m
aqueous solution of K2S dissolves
into 3 particles?
The change in the freezing point of the solution is 1.1°C.
What is freezing point depression?The freezing point depression is a colligative property thus we must take note of the number of particles in solution.
Using;
ΔT = k m i
k = 1.86 °C/m
m = 0.195 m
i = 3
ΔT = 1.86 °C/m * 0.195 m * 3
ΔT = 1.1°C
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Answer:
1.0881
Explanation:
Correct answer for Acellus
Se prepara 0,150dm3 de solucion poh=11,20 a partir de 10,00cm3 de una solucion acuosa de hno3 (( m=63,0g/mol). la concentracion de la solucion concentrada expresada en %m/v es?
Answer:
Translate your language to English ok
Ammonia gas occupies a volume of 450. mL at a pressure of 720. mm Hg. What volume will it occupy at standard pressure?
Show your work Please!!!!
Suppose you add a cup of sugar to hot water and all of the sugar dissolves. then the water cools and some of the sugar is seen as a solid on the bottom of the beaker. explain why this happened.
Answer:
its becuz the water is not capable to disolve all the salt it has limits and ones it reaches its limit it wont have the ability to disolve any salt
When methane, CH4, is combusted, it produces carbon dioxide, CO₂, according to the unbalanced equation: CH4 +0₂ - CO₂ + H₂O.
Write the balanced equation for this reaction, and explain how it is possible for 10 grams of methane fuel to burn and emit 27 grams of carbon dioxide. Discuss whether or not this reaction obeys the law
of conservation of mass. (5 points)
The balanced equation will be [tex]CH_4 + 2O_2 --- > CO_2 + 2H_2O[/tex]
Stoichiometric problemsThe balanced equation of the reaction would be as follows:
[tex]CH_4 + 2O_2 --- > CO_2 + 2H_2O[/tex]
The mole ratio of methane to carbon dioxide is 1:1.
10 grams of methane will give 10/16 = 0.625 moles
0.625 moles of carbon dioxide would give 0.625 x 44.01 = 27.506 grams.
Thus, 10 grams of methane will produce approximately 27 grams of carbon dioxide stoichiometrically.
The reaction obeys the law of conservation of mass because the atoms of all the elements before and after the reaction are balanced.
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●
As a solution becomes more basic or alkaline, how does it affect the concentration of
H3O* and OH ions?
Why is aluminum considered a nonrenewable resource?
A scuba diver uses compressed air to breath under water. He starts with an air volume of 3.20 L at sea level (1 atm) at a temperature of 30°C. What is the volume of air in his tank at a depth of 100 ft (3 atm) and a temperature of 24°C?
2.56 L is the volume of air in his tank at a depth of 100 ft (3 atm) and a temperature of 24°C.
What is an ideal gas equation?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
Given data:
[tex]P_1=1 atm[/tex]
[tex]V_1=3.20 L[/tex]
[tex]T_1[/tex]=30°C
[tex]P_2=3 atm[/tex]
[tex]V_2=?[/tex]
[tex]T_2=24°C[/tex]
Using the equation:
[tex]\frac{P_1V_1}{T_1}[/tex] =[tex]\frac{P_2V_2}{T_2}[/tex]
[tex]V_2[/tex] =(1 atm x 3.20 L x 24°C) ÷ 30°C
[tex]V_2[/tex] = 2.56 L
Hence, 2.56 L is the volume of air in his tank at a depth of 100 ft (3 atm) and a temperature of 24°C.
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