suppose you wanted to compare two different stain removers to learn which one was better at removing food stains from clothing. In your test, which variable would you need to control ?
Answers
Answer:
The amount/type of stain
Explanation:
You would want to ensure that the stain was the same in both samples.
Related Questions
Which set of laboratory equipment would most likely be used with a crucible
Answers
Answer:
That should be crucible tong
Biodiversity is important for the sustainability of ecosystems. However, many of the human actions that are aimed at growing communities are decreasing the biodiversity of these areas, leaving populations and ecosystems vulnerable. As human populations grow, the terrestrial and aquatic ecosystems they use may be transformed by the efforts of human beings and biodiversity losses typically accompany these processes. Which of these actions decrease biodiversity and threaten sustainability? Select ALL that apply.
A Invasive (non-native) species may outcompete native species for food and habitat. Invasive (non-native) species may outcompete native species for food and habitat.
B Regulated hunting seasons artificially decrease hunted populations, often leading to extinctions. Regulated hunting seasons artificially decrease hunted populations, often leading to extinctions.
C Pollution from building and commercialization can create health problems in exposed organisms. Pollution from building and commercialization can create health problems in exposed organisms.
D Decreased use of pesticides and fertilizers can allow for increased damage to plant life. Decreased use of pesticides and fertilizers can allow for increased damage to plant life.
E Habitat destruction reduces or eliminates the food resources and living space for most species. Habitat destruction reduces or eliminates the food resources and living space for most species.
Answers
The actions by humans that decrease biodiversity and threaten sustainability are;
Regulated hunting seasons artificially decrease hunted populations, often leading to extinctions.Pollution from building and commercialization can create health problems in exposed organisms.Habitat destruction reduces or eliminates the food resources and living space for most species.What is biodiversity?The term biodiversity has to do with the existence of different species that exist in an ecosystem. In a given ecosystem, there could be several species that exist together. This biodiversity is very much important for the continuity of balance in nature.
The actions by humans that decrease biodiversity and threaten sustainability are;
Regulated hunting seasons artificially decrease hunted populations, often leading to extinctions.Pollution from building and commercialization can create health problems in exposed organisms.Habitat destruction reduces or eliminates the food resources and living space for most species.Learn more about biodiversity:https://brainly.com/question/13073382
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what is the sequence of events from the arrival of an action potential at the synaptic knob until the release of neurotransmitter into the synaptic cleft?
Answers
The sequence of events at the neuromuscular junction is: 1. Arrival of the action potential at the synaptic knob, 2. Release of ACh into the synaptic cleft, 3.Binding of ACh to ACh receptors in the motor end plate, 4.Generation of action potential in sarcolemma, 5.Removal of ACh from the cleft by acetylcholinesterase
The action potential travels down the axon of the motor neuron and reaches the synaptic knob. This causes the release of the neurotransmitter acetylcholine (ACh) into the synaptic cleft. The ACh binds to ACh receptors in the motor end plate of the muscle fiber, which leads to the generation of an action potential in the sarcolemma (muscle cell membrane). The action potential then travels along the sarcolemma and deep into the muscle fiber, causing muscle contraction. Finally, the ACh in the synaptic cleft is rapidly broken down by the enzyme acetylcholinesterase to prevent continuous muscle contraction.
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Select the correct answer from each drop-down menu. sarah recently learned that o2 is found in the earth’s water bodies. she was amazed to know the proportion of o2 found in the ocean differs based on the water temperature. what fact did she find out? sarah recently learned that o2 is found in the earth’s water bodies. she was amazed to know the proportion of o2 found in the ocean differs based on the water temperature. she found out that parts of the oceans have a higher quantity of dissolved o2, whereas parts of the ocean have a lesser quantity of it.
Answers
Sarah discovered that the proportion of O2 in the ocean differs based on the water temperature. Some parts of the ocean have more dissolved O2, while other parts have less.
Sarah recently learned that the proportion of O2 found in the ocean differs based on the water temperature. Specifically, she found out that parts of the ocean have a higher quantity of dissolved O2, while other parts have a lesser quantity of it. This means that the amount of O2 present in the ocean can vary depending on the temperature of the water.
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The beta decay of cesium-137 has a half-life of 30.0 years. How many years must pass to reduce a 25.0 mg sample of cesium-137 to 9.38 mg?
Answers
Answer:
t = 42.4 years
Explanation:
To find the amount of time needed for the sample to decay, you need to use the half-life equation:
\(N(t) = N_0(\frac{1}{2})^{t/h}\)
In this equation,
-----> N(t) = final mass (mg)
-----> N₀ = initial mass (mg)
-----> t = time passed (yrs)
-----> h = half-life (yrs)
You can find how much time passed by plugging the given variables into the equation and solving for "t". The final answer should have 3 sig figs like the given values.
N(t) = 9.38 mg t = ? yrs
N₀ = 25.0 mg h = 30.0 yrs
\(N(t) = N_0(\frac{1}{2})^{t/h}\) <----- Half-life equation
\(9.38mg = 25.0mg(\frac{1}{2})^{t/30.0yrs}\) <----- Insert variables
\(0.3752 = (\frac{1}{2})^{t/30.0yrs}\) <----- Divide both sides by 25.0 mg
\(ln(0.3752) = ln((\frac{1}{2})^{t/30.0yrs})\) <----- Take the natural log of both sides
\(ln(0.3752) = \frac{t}{30.0yrs} ln(\frac{1}{2})\) <----- Rearrange the exponent
\(-9.803 = \frac{t}{30.0yrs} (-0.6931)\) <----- Solve the natural logs
\(1.1414= \frac{t}{30.0yrs}\) <----- Divide both sides by -0.6931
\(42.4 yrs= t\) <----- Multiply both sides by 30.0 yrs
A
B
Number of
Protons
20
D
9
Number of
Neutrons
20
D
Atomic
Number
A
Mass
Number
19
Using the periodic table, complete the table to describe each atom. Type in your answers,
Element
(symbol)
C
Answers
Using the periodic table we gave that;
A - 20
B - 40
C - Ca
Again;
D - 10
E - 9
F - F
What is the atomic and the mass numbers?An atom's atomic number (represented by the letter "Z") tells how many protons are in its nucleus. It designates an element on the periodic table in a certain way.
The total number of protons and neutrons in an atom's nucleus is indicated by the mass number, which is denoted by the letter "A." It represents a rough estimate of an atom's mass.
Isotopes are forms of an element with the same atomic number but various masses brought on by differing neutron counts.
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How does the temperature change when a layer of glass is added?
Answers
Answer:
thermal shock
Explanation:
the temperatures inside the glass jar should have continued to increase over time. Internal stresses due to uneven heating. This is also known as “thermal shock”.
In general, the thicker the glass, the more prone it will be to breaking due to the immediate differences in temperature across the thickness of glass.
Borosilicate glass is more tolerant of this, as it has a higher elasticity than standard silicon glass.
You may also note that laboratory test tubes and flasks are made with thinner walls, and of borosilicate glass, when designated for heating.
three difference between radicle and plumule
Answers
Answer:
1)RADICLE ->It is the embryonic root of the plant.
PLUMULE ->It is the embryonic shoot of the plant.
2)RADICLE ->It grows downwards into the soil.
PLUMULE ->It grows upwards into the air.
3)RADICLE ->Radicle is the first part of the seedling.
PLUMULE -> Plumule grows after the radicle.
4)Radicles are negatively phototropic. Plumule is positively phototropic.
i am glad i helped
what is meant bt absolute 0 temperature?
Answers
Absolute zero is an idea in thermodynamics that describes the lowest energy system.
Explanation:Thermodynamics
Thermodynamics is the study of thermal energy and heat. One of the most important ideas in thermodynamics is entropy. Entropy is defined as the chaos within a system. Chaos is the movement or different orientations of molecules in a system. Entropy is related to temperature; the higher the temperature, the higher the entropy. High entropy means there is a large amount of chaos in a system, while low entropy is low chaos.
Absolute zero
Absolute zero occurs when the temperature of a system is 0 kelvin or -273.15 °C. Zero kelvin is the theoretical temperature in which entropy equals 0. This means that there is no movement or energy within a system. Absolute zero is the lowest energy a system can possibly have.
When meso-2,3-epoxybutane is treated with aqueous sodium hydroxide, two products are obtained. Draw both products and describe their relationship.
Answers
When meso-2,3-epoxybutane is treated with aqueous sodium hydroxide (NaOH), it undergoes a trans ring opening reaction, resulting in the formation of a mixture of enantiomeric 2,3-butanediols.
This reaction is known as an epoxide ring-opening reaction.
Here's the mechanism for the reaction:
1) The nucleophilic hydroxide ion (OH-) attacks the less hindered carbon of the epoxide ring, leading to the formation of an alkoxide intermediate.
2) The alkoxide intermediate is protonated by water, resulting in the formation of the corresponding trans-2,3-butanediol as a major product.
3) The trans-2,3-butanediol obtained from the previous step is a meso compound, meaning it has an internal plane of symmetry. Consequently, it is achiral and does not exhibit optical activity.
4) However, during the ring-opening process, the epoxide can also undergo an inversion of configuration, resulting in the formation of its enantiomer.
Therefore, the overall reaction gives a mixture of enantiomeric 2,3-butanediols, where the trans-2,3-butanediol is the major product, and its enantiomer is the minor product.
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Why are foods that have a high pH pressure processed?
a. the higher pressure helps tenderize and make them edible
b. their low acidity makes them more prone to microbial growth
c. the shorter processing time preserves more of their nutrients
d. all of the above
Answers
The pressure of a gas is 780 torr when its volume is 400. mL and the temperature is 20.0°C. If the gas is allowed to expand to 500. mL at 25.0°C, what will the pressure be?
Answers
As volume increases, pressure decreases. This can be deduced from the equation above: P1V1 equals P2V2 and so on. P2 = (780 torr)(400 mL) (500 mL) P2 = 780 torr x 400/500 mL/ 624 torr pressure.
What will the gas's pressure be?As a result, the gas pressure that a gas experiences is equal to the product of the forces the gas molecules exert on the walls of the its container divided by the entire surface area of a container walls.
Why is there pressure in petrol?The force created when gas molecules slam into surfaces of objects produces gas pressure (Figure 1). Even though there is very little force involved in each collision, any surface with a sizeable area is subject to many of them quickly, which can lead to a high pressure.
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What would be the effect of each of the following sources of error on the molarity of H2SO4 determined in this experiment? State whether the concentration of H2SO4 obtained would be too high or too low. Explain your answer briefly.
a. The burette is contaminated with an acid solution.
[1 mark]
•
b. The burette contains a large air bubble in the tip, which disappears during the titration [1mark]
c. A small volume of the acid is spilled when you transfer it into the Erlenmeyer flask
[1 mark]
Answers
Answer:
The burette is contaminated with an acid solution- The concentration is too high
The burette contains a large air bubble in the tip, which disappears during the titration- The concentration of the acid is too low.
A small volume of the acid is spilled when you transfer it into the Erlenmeyer flask- The concentration of the acid is too low.
Explanation:
The molality of a solution is the number of moles of solute per liter of solution. The concentration of an unknown solution is obtained by titration against a standard solution of acid or base whose concentration is known. It is a volumetric method of analysis.
If the burette is contaminated with the acid, then the concentration of the base that reacts with the acid is less than the stated amount and consequently the concentration of the acid calculated is higher than it should be.
If the tip of the burette contains air bubbles, the volume of the acid reported is less than the volume of acid actually delivered during the titration hence the calculated concentration of the acid is too low.
If some volume of acid is spilled when you transfer the acid into the Erlenmeyer flask, the volume of the acid reacted is decreased and consequently the calculated concentration of the acid is too low.
Select six different types of energy. physical light chemical mechanical atomic electrical mental heat
Answers
Answer:
Mechanical energy is energy that results from movement or the location of an object. Mechanical energy is the sum of kinetic energy and potential energy.
Explanation:
Nuclear energy is energy resulting from changes in the atomic nuclei or from nuclear reactions.
Example: Nuclear fission, nuclear fusion, and nuclear decay are examples of nuclear energy. An atomic detonation or power from a nuclear plant are specific examples of this type of energy.
at sea level, what percentage of the air we breathe is oxygen?
Answers
At sea level, the air we breathe is 21% oxygen. This means that for every 100 molecules of air we inhale, 21 of them are oxygen molecules.
The remaining 79% is mostly nitrogen, with small amounts of other gases such as argon and carbon dioxide. The percentage of oxygen in the air can vary slightly depending on factors such as altitude and location.
For example, at higher altitudes, the percentage of oxygen decreases because there is less atmospheric pressure.
Additionally, air pollution can also impact the percentage of oxygen in the air. It is important for our bodies to receive this essential gas to function properly, as oxygen is necessary for cellular respiration and energy production.
At sea level, the percentage of oxygen in the air we breathe is approximately 21%. The air is primarily composed of nitrogen (around 78%), oxygen, and trace amounts of other gases such as argon, carbon dioxide, and water vapor.
The composition remains relatively consistent throughout the lower atmosphere, ensuring that we have a sufficient supply of oxygen to sustain life at varying altitudes.
However, air pressure does decrease with elevation, which can affect the availability of oxygen in higher altitudes.
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Il give brainliest question in the picture
Answers
Answer:
Nitrogen and Argon
Explanation:
These gases are part of a class of "noble" gases because they don't react with anything.
determine whether the sequence is increasing, decreasing, or not monotonic. an = 4ne^−7n increasing decreasing not monotonic Is the sequence bounded?
Answers
A monotonic sequence is a sequence of numbers in which the terms consistently increase or consistently decrease as the sequence progresses. The sequence an = 4ne^(-7n) is decreasing. To determine if the sequence is bounded, we need to analyze the behavior of the sequence as n approaches infinity.
In the monotonically increasing sequence, each term is greater than or equal to the previous term. In the monotonically decreasing sequence, each term is less than or equal to the previous term. In the non-monotonic sequence, the terms do not consistently increase or decrease. As n approaches infinity, the term 4ne^(-7n) approaches 0. Therefore, the sequence is bounded from above by 0. However, the sequence is not bounded from below as it continues to decrease indefinitely. Therefore, the sequence is bounded above but not bounded below.
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Calculate the relative formula mass of strontium nitrate, Sr(NO3)2.
(relative atomic masses: N = 14, O = 16, Sr = 88)
Answers
Answer:
its 210
Explanation:
Just add all atomic mass used in the formula together: 2*(14+16*3)+88= 2*62+88=124+88=210
Hope this was helpful
The relative formula mass of strontium nitrate Sr(NO₃)₂ is 210
The relative atomic masses of N, O and Sr are 14,16 and 88 respectively.
In calculating the relative atomic mass of an element with isotopes, the relative mass and proportion of each is taken into account. Adding the atomic masses together gives the relative formula mass of a compound
So, relative atomic mass of Sr(NO₃)₂ is calculated as
88+ 2(14+16×3) = 210
The atomic mass constant (symbol: mu) is defined as being 1/12 th of the mass of a carbon-12 atom. Since both quantities in the ratio are masses, the resulting value is dimensionless; hence the value is said to be relative atomic mass.
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A gas ocupies a rigid container at a pressure
of 54.5 kPa with a temperature of 19.0 °C.
What will the new pressure if the gas is
cooled to -25 °C?
Answers
Answer:
P₂ = 46.3 KPa
Explanation:
Given data:
Initial pressure = 54.5 KPa
Initial temperature = 19.0 °C (19+273 = 292 K)
New pressure = ?
Final temperature = -25°C (-25+273 =248 K)
Solution:
According to Gay-Lussac Law,
The pressure of given amount of a gas is directly proportional to its temperature at constant volume and number of moles.
Mathematical relationship:
P₁/T₁ = P₂/T₂
Now we will put the values in formula:
13.0 atm / 293 K = P₂/375 K
P₂ = 54.5 kpa × 248 K / 292 K
P₂ = 13516 KPa. K /292 K
P₂ = 46.3 KPa
29. Which type of orbital is shown?
Z
Y
Х
Answers
Answer:
b
Explanation:
How many protons, neutrons, and electrons are there?
Answers
Answer:
proton-27
electron-25
neutron-35
Explanation:
In each pair of statements, choose the example that is more reliable.
Statement 1
The company Herbal Remedies Inc.
announced today that its antiobesity skin
treatment is safe and effective.
Statement 2
The US Food and Drug Administration (FDA)
announced today that cancer treatment X,
manufactured by Pharma Inc., is safe and
effective.
Statement 1
An independent chemical analysis paid for by
local residents determined that wells are
contaminated with dioxin at a concentration
of 3 ppb.
Statement 2
The chemical company Chemicals Inc. insists
that local groundwater has not been affected
adversely by a leak in its waste handling
system.
Answers
Answer:
"statement 2" for the first pair and "statement 1" for the second pair
Explanation:
example 1: 0.4 gm of compound c was reacted with 3.0ml of compound d (2.8 m in ether) to give 0.5 gm of a product. identify the expected product and calculate the theoretical and percent yield.
Answers
The expected product in the reaction of compound C with compound D is unknown based on the information provided. To calculate the theoretical yield, we need the balanced chemical equation for the reaction. Without this information, we cannot determine the theoretical yield or calculate the percent yield.
However, if we had the balanced equation, we could use the given amounts of compound C and compound D to determine the limiting reactant and calculate the theoretical yield.
The percent yield is then calculated by dividing the actual yield (0.5 gm) by the theoretical yield and multiplying by 100. Without the necessary information, we cannot provide specific values for the theoretical or percent yield in this case.
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why are vials made from vapor glass stronger then typical vials?
I.they contain aluminum instead of boron.
II. They submerged in hot salt bath.
III. They formed out of long glass tubes.
A) I
B) I and II
C) I and III
D) I, II, and III
Answers
Answer:
2
Explanation:
I'm not that sure plz tell me if this is right
Leandra is learning about chemical reactions and she wants to examine the information that is included in a chemical equation. Which pieces of information does a chemical equation include? Choose the three that apply. A. the kinds of atoms that form during a reaction B. the kinds of molecules involved in the reaction C. the kinds of elements that make up a molecule D. whether the molecules are products or reactants E. whether the products have more mass than the reactants
Answers
Answer:
A C E
Explanation:
i just got my teacher to help me and thants the answers she gave me
A. the kinds of atoms that form during a reaction. C. the kinds of elements that make up a molecule. D. whether the molecules are products or reactants
Chemical equationThe kinds of atoms that are formed during a reaction, types of elements that make up a molecule and the molecules are products or reactants are the pieces of information which provides by a chemical equation.
Chemical equation also gives us information about the number of atoms that participate during the chemical reaction as well as the amount or concentration of products produced in the end of chemical reaction so we can conclude that chemical equation gives us valuable and important information about elements.
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Waves transfer energy. What have you observed about light, sound, or water that could support this claim?
Answers
Waves transfer energy therefore what we have observed about light, sound, or water that could support this claim is that Light warms objects when it shines on them.
What is a Wave?This is referred to as a disturbance or variation that transfers energy progressively from point to point in a medium and it is usually in a regular and organized manner.
Sound waves from a powerful stereo can make the floor vibrate and the water waves crash on the beach with force which are therefore the observations which support the claim that waves transfer energy and is the correct choice.
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Rock whose texture, mineralogy, or chemical
composition has been altered without melting it.
Answers
Answer:
I believe it would be C or B
How many c atoms are there in 5K2CO3
Answers
Answer:
8 atoms.
Explanation:
Convert the following absolute temperatures to centigrade.
i) 0 K
ii) 298 K
iii) 323 K
iv) 423 K
SHOW STEP BY STEP
Answers
Answer:
0 K
\({ - \bf{273 \degree C}}\)
298 K
\({ \tt{ = 298 - 273}} \\ = { \bf{25 \degree C }}\)
323 K
\({ \tt{ = 323 - 273}} \\ = { \bf{50 \degree C}}\)
423 K
\({ \tt{ = 423 - 273}} \\ = { \bf{150 \degree C}}\)
1.T=[£+273]
=273
It is because kelvin temperature is absolute zero.
Calculate the temperature of 2.0 moles of a gas occupying a volume of 5.0 L at 2.46 atm. (R = 0.08125 L atm/mol L)
a. 75 K
b. 348 K
c. 198 K
d. 0.013 K
Answers
Answer:
Hi how are you doing today Jasmine
Answer: a. 75K
Explanation:
https://socratic.org/answers/200353
