Two students are comparing scientific experiments to investigations. They came up with the following ideas.

Student A: Testing plant growth in different types of soils
Student B: Comparing the water level in a lake during different times of the year

One student gave an example of an investigation and the other gave an example of an experiment. Which student gave an example of a scientific investigation?

(5 points)

Student A because it requires a hypothesis
Student B because it requires a hypothesis
Student A because it can be done in natural settings od
Student B because it can be done in natural settings​

Answer:

20 meters

Explanation:

The bike is moving at a rate of 4 meters per second. In 5 seconds, the bike would have gone 20 meters

4 m/s x 5s = 20 m

Answer:

20 miles

Explanation:

Answer:92.1g

Explanation:

This means that the reaction consumed4.004moles NaCl⋅2 moles Na2moles NaCl=4.004 moles NaConvert this to grams by using the element's molar mass4.004moles Na⋅22.99 g1mole Na=92.1 g

The freezing point of the solution after you add an additional 1.34 g is -0.808°C.

A solution's freezing point is lower than the pure solvent's freezing point. This means that for freezing to happen, a solution needs to be cooled to a lower temperature than the pure solvent.

We use the equation: to determine the mass of the solution

Density = mass/volume

1.05 g/ml = mass/ 50ml

mass = 1.05×50

mass = 52.5g.

Percentage of magnesium chloride in the solution is 1.52%

Mass of magnesium chloride in the solution = 1.52 % of 52.5 g

Mass of magnesium chloride in the solution = 1.52/100×52.5

Mass of magnesium chloride in the solution = 0.798g

The following equation is used to determine depression in freezing point:

ΔTf = Freezing point of pure solution - Freezing point of solution

ΔTf = i Kf m

Freezing point of pure solution - Freezing point of solution = i Kf m

m =  m solute × 100/M solute × W solvent

Given values,

Freezing point of pure solution (water) is 0°C

i is Vant hoff factor = 2.5

Kf molal freezing point elevation constant = 1.86°C/m

m solute given mass of solute (magnesium chloride) = [0.798 + 1.34] g

m solute = 2.138 g

M solute molar mass of solute (magnesium chloride) = 95.2 g/mol

W solvent mass of solvent (water) = [52.5 - 0.798] g = 51.702 g

substitute the given values,

0 - Freezing point of solution = 1×1.86×2.138×1000/95.2×51.702

Freezing point of solution = -0.808°C.

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Complete question is " A 50 mL solution is initially 1.52% MgCl₂ by mass and has a density of 1.05 g/ml

What is the freezing point of the solution after you add an additional 1.34 g MgCl₂? (Use i = 2.5 for MgCl₂)."

When a 211-mL sample of a 0.285 M CaCl₂ solution is left on a hot plate overnight and the following morning, the solution is 1.25 M, the volume of water evaporated from the 0.285 M CaCl₂ solution is 48.108 ml.

Molarity (M) is defined as the ratio of the number of moles of solute present in a solution to the volume of the solution in litres.

given here,

Molarity of the original solution(M₁) = 0.285M

Volume of the original solution(V₁) = 211 ml

Molarity of  the solution in the morning (M₂) = 1.25 M

Volume of the solution in the morning (V₂) = ?

We will calculate the volume of the solution in the morning by using the formula:

M₁ × V₁ = M₂ × V₂

⇒0.285 M× 211 ml = 1.25 M × V₂

⇒V₂ = 0.285 M× 211 ml / 1.25 M

⇒V₂= 48.108ml

The volume of water evaporated from the 0.285M CaCl₂ solution is 48.108 ml.

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Answer:

The answer is C.

Explanation:

Answer:

C is right i yeah C is right

Explanation:

Oogenesis can be defined as a process of differentiation of egg cell (ovum), into a mature ovum that further develops after fertilization. In humans, oogenesis begins in the early stage of embryonic development, during whcih primary oocyte performs meiosis I and forms secondary oocyte.

a) The mole ratio is 2/1

b) The mole ratio is 4/6

c) The mole ratio is 2/3

We have to note that the mole ratio is the ratio of the stoichiometric coefficient that we have between two reactants that can be found in an equation. In the case of the reaction equations that we have, we must look closely at each equation.

As we can see, each of the reaction equations is balanced and we can now be able to obtain the mole ratio of each of the reaction as shown in the answer above.

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1.50g of hydrofluoric acid is produced if 3.00 g of hydrogen reacts with excess fluorine with a 25 percent yield.

The balanced equation for the reaction of hydrogen (H2) and fluorine (F2) to form hydrofluoric acid (HF) is:

H2 + F2 -> 2HF

To calculate the amount of HF produced, we'll use the concept of theoretical yield and percent yield.

The theoretical yield is the maximum amount of product that can be formed based on the amount of reactants used.

Here, we're given that 3.00 g of hydrogen is used, so to find the theoretical yield of HF, we'll use the molar ratio of hydrogen to hydrofluoric acid in the balanced equation.

1 mol of H2 produces 2 mol of HF

So, 3.00 g of H2 produces 2*3.00g = 6.00g of HF

Percent yield is the ratio of the actual yield to the theoretical yield multiplied by 100%.

It's given that the yield is 25%.

So the actual yield of hydrofluoric acid will be:

Actual yield = (Theoretical yield) x (percent yield/100)

Actual yield = 6.00g x (25/100)

Actual yield = 1.50g

So, 1.50g of hydrofluoric acid is produced if 3.00 g of hydrogen reacts with excess fluorine with a 25 percent yield.

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Answer:

Molarity of a solution is defined as

the amount of a substance in a certain volume of solution or the moles of a solute per liters of a solution and also known as the molar concentration of a solution.

The units of molarity are M or mol/L

Define molarity of a solution.

Molar concentration or Molarity is a measure of the concentration of a chemical species, in particular of a solute in a solution, in terms of amount of substance per unit volume of solution.

_____

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Answer:

Separation by density

Hope this helps

Answer:

Which one do you need the answer to?

Explanation:

Titration is a quantitative analysis method for determining the concentration of a substance from a measured titrant. According to the equation, if the reactants are halved, the amount of H2O produced will be halved.

The molecular equations for sodium hydroxide, hydrochloric acid, sodium chloride, and water can be expressed as:

 HCl + NaOH ⇒ NaCl + [tex]H_{2}[/tex]O

In the given equations, the spectator ions and the ionic equation can be distinguished as follows:

H⁺ + Cl⁻ Na⁺ + OH⁻ ⇒ Na⁺ + Cl⁻ + 2H⁺ + O⁻²

The net ionic equation is:

 H⁺ + OH⁻ ⇒ [tex]H_{2}[/tex]O

From the above equation, we can see that the production of water molecules depends on the number of reactants. The reactants are,

H⁺ and OH⁻.

Therefore, when the number of reactants is halved, the resulting water molecules are halved.

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Explanation:

frequency = 1 wave/10s = 0.1 Hz

wavelength = 5.8 m

speed = wavelength × frequency

= (5.8 m)(0.1 Hz)

= 0.58 m/s

Answer:

4400, and 0

Explanation:

since they traveled 2200 in one direction, to return home they must travel that distance again, so they travel 4400

displacement is the distance from the start point, so since they are back home at the end of the trip, they did not get displaced at all

if you have any questions, leave them in the comments and i will try to answer them, if this helped, pls give brainliest

Answer:

My answer to the question is 4400 and 0

Some examples of evidence that support Darwin's theories of evolution and natural selection , such as fossils and similarities between related living organisms.

Darwin employed certain sorts of evidence to support his hypothesis of natural selection, and these types of evidence are still used today. Examples include fossils and similarities between related living animals. Others, like DNA analysis, were unavailable to Darwin's generation but are now employed by scientists to further our understanding of evolution.  evidence supporting evolution: fossil strata, remains of extinct organisms, similarities between current-day organisms, DNA similarities, and embryonic similarity. Artificial selection, or breeding, is a crucial sort of evidence that Darwin looked at and is being looked at and employed today.

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Answer:

a) red, blue, and violet

b) orange, yellow, and green

C) red, orange, and yellow

D) blue, indigo, and violet​

The life cycle of a star the size of our sun starts with a nebula, a huge cloud of dust and gas. The gravity of the nebula compresses the cloud until the atoms fuse together, creating a star. This stage is known as pre-birth.

Next, the star enters a main sequence phase, where it shines brightly for millions of years, powered by nuclear fusion.

Eventually the star will slowly run out of hydrogen and the fusion process will become less and less efficient. The star will expand and become what is known as a red giant. This marks the end of the main sequence phase.

After this point, the star expels its outer layers, leaving behind a small, hot core called a white dwarf. It will continue to cool down until it becomes a black dwarf.

If the star is at least 5 times bigger than our sun, it will enter a different life cycle. After the red giant phase, the star will undergo a supernova explosion, which will spew dust and gas into the surrounding areas. These remainders will later form new stars, planets, and other cosmic bodies. What's left of the star will become a neutron star or a black hole.

Answer & Explanation:

It is NOT POSSIBLE to determine a person's genotype if that person presents the dominant trait

Answer:

the molar mass of (NH4)3PO4 is 149.09 g/mol

The dominant phenotype for sheep color is wool because it is the most common color seen in sheep.

What do you mean by Phenotype?

Phenotype is the physical, biochemical, and physiological characteristics of an organism, as determined by both genetic makeup and environmental influences. It is the physical expression of an organism's genes, and can be seen in its morphology, development, and behavior.

Wool is usually white or off-white in color and is the result of a dominant gene. The recessive phenotype for sheep color is non-wool, which is usually a darker color, such as black, brown, or gray. This is the result of a recessive gene and is less common than the dominant gene.

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Answer:

added to what? base? if its added to base then it will increase in pH. H2S04(sulphuric acid is strong) so the pH is ard 3

The expression is  [tex]\frac{(h+2)}{4}[/tex] which can be solved by BODMAS rule

The abbreviation BODMAS, which stands for "Brackets, Order of powers or roots, Division, and Multiplication," is followed by the BODMAS rule. A stands for addition and S for subtraction. According to the BODMAS rule, multi-step mathematical statements must be solved in the BODMAS order from left to right. Similar to how Addition and Subtraction depend on which comes first in the sentence, Division and Multiplication are thought of as interchangeable operations.

The expression can be written as follows WE have 2 quantities h and 2

Their sum can be written as h+2 Now We have the sum divided by 4 so it can be written as : [tex]\frac{(h+2)}{4}[/tex]

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When the arrangement of atoms changes in a substance, the properties of the substance can change as well. The different arrangements of atoms can lead to different chemical and physical properties.

For example, if the atoms of a substance are rearranged to form a new compound, the new compound will have different chemical properties than the original substance. A new compound may have a different color, odor, reactivity, or melting point than the original substance.

Changing the arrangement of atoms without changing the chemical composition can change the physical properties. For example, a crystalline solid has atoms or molecules arranged in a regular, repeating pattern. This arrangement gives the material unique properties such as density, melting point, and hardness. If the arrangement of atoms and molecules changes, the properties of solids can also change.

In summary, when the arrangement of atoms in a substance changes, the properties of the substance can also change. Different arrangements of atoms have different chemical and physical properties.

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Answer:

0.0272 moles

Explanation:

The number of moles of acid that were neutralized can be found by multiplying the volume of the base (in liters) by its concentration (in moles/liter) and then multiplying that value by the stoichiometric coefficient of the acid in the balanced chemical equation for the neutralization reaction.

To begin, we need to convert the volume of the base from milliliters to liters.

50.40 mL = 0.0504 L

Next, we can multiply the volume of the base (in liters) by its concentration (in moles/liter) to find the number of moles of base used in the titration.

0.0504 L * 0.542 M = 0.0272 moles

Since this is a neutralization reaction between a monoprotic acid and a strong base, the acid:base ratio is 1:1.

So the acid that has been neutralized is also 0.0272 moles.

Answer:

1) in excess

Explanation:

Copper oxide is insoluble in water, while acid is soluble in water

In the box on a periodic table  we can find its atomic number, symbol, average atomic mass, and (sometimes) name of the element.

By the 20th century, it was clear that atomic numbers, not atomic masses, were involved in the periodic relationship. The periodic law, a more recent formulation of this relationship, states that an element's properties are a periodic function of its atomic number.

The elements are arranged in a modern periodic table in increasing order of their atomic numbers, and atoms with comparable properties are grouped in the same vertical column (Figure below). With its atomic number, symbol, average atomic mass, and (sometimes) name, each box represents an element. The elements are grouped in 18 vertical columns called groups and seven horizontal rows known as periods or series.

Each column's header lists the names of its groups. Roman numerals and capital letters have traditionally been used on labels in the United States. The IUPAC advises using the digits 1 through 18, and these labels are more widely used. Parts of two of the rows, totaling 14 columns, are typically written below the table's main body in order for it to fit on a single page.

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