Question 1 of 10
Which of the following is a testable hypothesis?
A. Green toothpaste tastes better than blue toothpaste or red
toothpaste.
B. It's wrong to not brush your teeth before you have an important
conversation with someone.
C. Smart, careful, healthy people always brush their teeth.
D. If I brush my teeth, I will get fewer cavities than if I don't brush my
teeth.

Answer:

3.

Explanation:

Sodium chlorate has the formula NaClO3. We know this because sodium is Na, chlorine is Cl, and because of naming rules. When a compound ends in -ate, it has 3 oxygen atoms. This is the naming rule list with chlorine as the example:

perchlorate: 4 O atoms

chlorate: 3 O atoms

chlorite: 2 O atoms

hypochlorite: 1 O atom

Ions are simply referred to as electrically charged atoms. Ions are formed when atoms lose or gain electrons to become positively or negatively charged.

Positively charged atoms are called cations (+) while negatively charged atoms are called anions (-).

According to this question, ions are electrically charged that can be formed when a metal reacts with a non-metal.

Metals like calcium, pottasium etc. lose electrons to form positive ions or cations while non-metals such as nitrogen, oxygen etc gain electrons to form negative ions or anions.

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Fluorine has the strongest base among fluorine, chlorine and bromine.

Fluorine belongs to the group of halogens.  It is represented with the letter F and has an atomic number 9. Fluorine is the smallest element among the halogens and hence its electrons are attached very strongly with the nucleus. As a result, fluorine has the most tendency to accept electron to complete its valence shell and therefore is the strongest base.

Bases are the molecules or ions that can accept electrons to complete their outer valence shell. This justifies fluorine being the strongest base among halogens. Bases are generally bitter in taste, with a soapy touch. A pH above 7 specifies basicity.

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The rate of effusion of helium under same conditions as that of ammonia  is 4.897 mole/min.

Rate of effusion of ammonia is 0.49 times the effusion of helium.Thus, to find out effusion of helium ,effusion of ammonia is divided by 0.49.

Thus, effusion of helium=effusion of ammonia/0.49

=2.40/0.49

=4.897 mole/min.

Effusion relates to the ability of gas to travel through a small opening.Rate of effusion of a gaseous substance is inversely proportional to square root of it's molar mass.The relationship between molar mass and rate of effusion is called Graham's law.

Effusion rate directly depends on the average velocity with which a particle moves.Higher the velocity of particles,higher is the effusion rate.

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The density of metal block in grams per cubic centimeter is 10.70 g/cm³.

Given,

Mass of metal block = 5.16 lb  

1 lb = 453.592 g

5.26 lb = 2340.536 g

The volume of metal block = 14 in 3

1 in = 2.5 cm

1 in 3 = 15.625 cm³

14 in 3 = 218.75 cm³

Density is defined as the mass per unit volume of a substance. Or, it is the ratio of mass to the volume of the substance.

As we know,

Density = mass/volume

Or, density = 2340.536 / 218.75

Or, density = 10.70 g/cm³

Therefore, the density of the metal block is 10.70 g/cm³.

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To see how the concentration of the acid would affect the rate at which the steel corroded

In the given question it is said that a chemist is studying the effect of acid rain on the steel in bridges and because of concentration of the acid it would affect the rate at which the steel corroded and in the corrosion of steel which is present in bridges is the electrochemical process that require the simultaneous presence of moisture and oxygen and acid rain is a form of precipitation with acidic component such as sulphuric acid or nitric acid that fall to the ground from the atmosphere in wet or dry form. and in the steel bridge when the acid rain is fall concentration of acid which is present on acid rain will effect the bridge and affect the rate at which the steel corroded

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The no. of sodium ions present in the solution are found to be 3.85×10²³.

1 mol Na₂SO₄ contains 2 mol na+ ions then ions contains by 0.32 mol na₂SO₄ is given by 0.32× 2 = 0.64 na+ ions.

Since 1 mol of na+ ions Avogadro no. Of ions that is 6.022×1023.

So, 0.64 na+ ions contains 6.022×10²³× 0.64 = 3.85×1023.

Thus the solution contains 3.85×10²³ na⁺ ions.

Now, we calculate the mass of 0.32 mol Na₂so₄.

We know that mass of one mol of Na₂SO₄ is equal to molar mass, that is 142g.

Then, the mass of 0.32 mol Na₂so₄ is calculated as 0.32× 142 = 45.45grams.

A chemical compound’s molar mass is calculated by dividing its mass by the number of moles measured in moles that make up the sample of the compound.

The proportionality factor that connects the quantity of substance in a sample to the number of constituent particles in that sample is called the Avogadro constant. The reciprocal mole, which is its SI unit, is defined precisely as NA = 6.02214076×10²³ mol⁻¹.

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The hydrogen ions build up in high concentration in the lumen of the thylakoid. They pass through an enzyme called ATP synthase, and their movement provides the energy needed to add a third phosphate to ADP (adenosine diphosphate) to form ATP (adenosine triphosphate).

might be a b

Answer:Other dude is right I just took the quiz.

Its B

Explanation

A recreational slide that has water running down it to lessen friction, sometimes requiring the user to sit on a mat or raft, and occasionally ending in a pool.

In Faribault, Minnesota, lived Herbert Sellner. His career as a designer began with the creation of furniture, followed by the design of children's toys and, most notably, the Water-Toboggan Slide. The slide, constructed in 1923, was a wooden sled that guests could sit on and ride down an incline into a lake.

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Answer:

black

Explanation:

An object which absorbs all wavelengths of visible light will appear black, and one which absorbs none will appear white.

Answer:

To find the formula of an ionic compound, first identify the cation and write down its symbol and charge. Then, identify the anion and write down its symbol and charge. Finally, combine the two ions to form an electrically neutral compound.

Explanation:

All the species mentioned do have resonance structures.

The Lewis structure is an arrangement that shows the number of electrons that are attached to each of the atoms in a compound. In this case, the structure consists of the symbol of the elements and the number of electrons pairs of or odd electrons attached to the element.

Sometimes, a single Lewis structure is insufficient when discussing the properties of a compound. We must then invoke a number of structure which we call the resonance structures.

The the species mentioned in the question do have resonance structures that are obtained by satisfying the octet rule as shown in the images attached to this answer.

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A nurse decides to move from England to India. The nurse currently makes 46,800 Euros as their annual salary. in Indian Rupees every month the nurse's salary will be Rs.  3,70,968

Let us Consider the following given data

The Nurse current salary is 46,800 Euros

We have to find 1 month's salary of the annual .

We know that one year contains 12 months .

Therefore 1 month's  salary = 46,800/12

   =3,900 euros per month

To find: The nurse's salary  every month in Indian rupee

1 Euro = Rs. 95.12

= 3,900 ×Rs.95.12

= Rs.  3,70,968 ( three lakh seventy thousand nine hundred sixty eight rupees in Indian currency .)

The nurse's salary in Indian rupees per month is 3,70,968 rupees

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Answer:

Pb(ClO₄)₂ (aq) + 2 NaCl (aq) -----> 2 NaClO₄ (aq) + PbCl₂ (s)

Explanation:

This chemical reaction is a double-displacement reaction. In these reactions, the cation of one compound is swapped with the cation of another.

So, lead (II) (Pb²⁺) from lead (II) perchlorate (Pb(ClO₄)₂) will be swapped with sodium (Na⁺) from sodium chloride (NaCl). When creating the new compounds, there may need to be more than one ion of a particular type in order to make the overall compound neutral.

An equation is balanced when there is an equal amount of each element on both sides of the reaction. If these amounts are unequal, you can add coefficients to modify the quantities of particular compounds.

The unbalanced reaction:

Pb(ClO₄)₂ (aq) + NaCl (aq) -----> NaClO₄ (aq) + PbCl₂ (s)

Reactants: 1 lead, 3 chlorine, 8 oxygen, 1 sodium

Products: 1 lead, 2 chlorine, 4 oxygen, 1 sodium

The balanced reaction:

Pb(ClO₄)₂ (aq) + 2 NaCl (aq) -----> 2 NaClO₄ (aq) + PbCl₂ (s)

Reactants: 1 lead, 4 chlorine, 8 oxygen, 2 sodium

Products:  1 lead, 4 chlorine, 8 oxygen, 2 sodium

The mass of water is 1.89g

Mass is a measure of the amount of matter that an object contains

Here given data is 1.23 g of butane reacts with excess oxygen and the reaction is

C₄H₁₀ + 13/2 O₂ →4CO₂ + 5H₂O

Mole of butane = 1.23/58.12g/mol⁻¹

Mole of butane = 0.021mol

We assume complete combustion, and know that each mole of butane gives off 5 mol of water upon combustion.

We know the molar quantity of butane then

5×0.021×18.01 = 1.89g

Mass of water is 1.89g

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Answer:

904.8 kg / m3

Explanation:

19.0 kg/0.021 m^3 = 904.761905 kg / m3

C2H6O is ethanol which is easily dissociate in aqueous solution because ethanol is easily soluble in water.

Aqueous solution is defined as a solution in which the solvent is water.

Example of aqueous solution are cola, salt water, base solution, salt solution etc., are some of the example of aqueous solution.

Non aqueous solution is defined as a solution obtained by dissolving solute in any liquid other than water.

Example of non aqueous solutions are ethene in dichloromethane and Sulphur  in carbon disulphide etc. are some of the example of  non aqueous solution.

Thus, C2H6O is ethanol which is easily dissociate in aqueous solution because ethanol is easily soluble in water.

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Considering the ideal gas law, the mass of ammonia is 5.321 grams.

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of gases:

P×V = n×R×T

In this case, you know:

Replacing in the definion of ideal gas law:

2.55 arm× 3 L = n×0.082 [tex]\frac{atmL}{molK}[/tex]× 298 K

Solving:

n= (2.55 arm× 3 L)÷ (0.082 [tex]\frac{atmL}{molK}[/tex]× 298 K)

n= 0.313 moles

Being the molar mass of ammonia 17 g/mole, the mass can be calculated as:

mass of ammonia= 0.313 moles× 17 g/mole

Solving:

mass ammonia= 5.321 g

Finally, the mass of ammonia is 5.321 grams.

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Answer:

If the temperature is increased, the average speed and kinetic energy of the gas molecules increase. If the volume is held constant, the increased speed of the gas molecules results in more frequent and more forceful collisions with the walls of the container, therefore increasing the pressure (Figure 1).

The way in which theories and models may be modified but are rarely discarded completely is shown in the geocentric and heliocentric models of the solar system are the fact that similar assumptions were made, but the main difference is the position of the earth and the sun.

This refers to the theory of the solar system that is based on the assumption that the earth is the center of the universe and the planets and sun move around it

This refers to the theory of the solar system that is based on the assumption that the sun is the central point of the universe and the planets and sun move around it

Hence, The way in which theories and models may be modified but are rarely discarded completely is shown in the geocentric and heliocentric models of the solar system are the fact that similar assumptions were made, but the main difference is the position of the earth and the sun.

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The required volumes are;

1)  2 mL

2)  4 mL

3)  5 mL

Now we know that the dilution formula can be used to obtain the quantity of a solution that could be used in the preparation of another by the use of serial dilution. In this case, we can see that an aliquot of the solution is taken and then made up to mark in order to obtain the concentration that we require as we are trying to carry out the process of the serial dilution.

Now let us try to see how we can be able to prepare the solutions that are required as follows;

To prepare 50mM of of calcium nitrate;

C1V1= C2V2

C1 = initial concentration’

V1 = initial volume

C2 = final concentration

V2 = final volume

C1 = C2V2/C1

C1 = 20.0 mL *  5.00 mM/50mM

C1 = 2 mL

2) 20.0 mL *  1.00 mM/ 5.00 mM

= 4 mL

3) 20.0 mL *  0.250 mM/1.00 mM

= 5 mL

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Answer:Which plate boundary and movement commonly create volcanoes that can result in the development of habitable islands?

 Sometimes, the plates collide with one another or move apart. Volcanoes are most common in these geologically active boundaries. The two types of plate boundaries that are most likely to produce volcanic activity are divergent plate boundaries and convergent plate boundaries

Explain how islands can be created by plate tectonics.

Explanation: These hot spots are able to independently melt the tectonic plate above them, creating magma that erupts onto the top of the plate. In hot spots beneath the ocean, the tectonic activity creates a volcanic mound. Over millions of years, volcanic mounds can grow until they reach sea level and create a volcanic island.

Answer:

4OH-→ 2H²O(l) + O² + 4e- (Anode)

2H+ → H²O (l) + 2e- (Cathode)

Explanation:

OH- ions are preferentially discharged at the anode since they have a less positive electrode potential (+0.40V) then chloride ions (+1.36)

H+ ions are preferentially discharged at the cathode since they have a less negative standard electrode potential (0.00) than Potassium (-2.92)

The correct answer is option b) Both atoms have Zeff of 1; therefore, Atom D is above Atom E in the same column because of the additional energy level.

The term "Zeff" refers to the effective nuclear charge, which is equal to the atomic number (number of protons) less the core electrons (all the electrons less the valence electrons).

Zeff = no. of protons -  no. of core electrons

Now, each circle in the image indicates a distinct energy level, with rising energy as one moves away from the nucleus. Since atom D has fewer energy levels than atom E, hence, it is placed above atom E in the periodic table.

Furthermore, according to the trends of the periodic table, atoms with the same number of valence electrons will be in the same column. Since atoms D and E both have a single valence electron. Hence, they are in the same column and have the same Zeff of 1.

Therefore, both atoms have Zeff values of 1, and Atom D is positioned above Atom E in the same column due to the additional energy level in atom E.

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Answer: 0.9152 g

Explanation:

32.0 mg/mL=

32.0/1000 g/ml=0.032 g/ml

0.032 g/ml*28.6 ml=

0.9152=0.9152 g

Answer:

0.25 grams He

Explanation:

To find the mass (grams), you need to multiply the given mole value by the atomic mass of helium. The atomic mass exists as a ratio which compares the mass of an element per every 1 mole. It is important to arrange this ratio in a way that allows for the cancellation of units (grams should be in the numerator in this case). The final answer should have 2 sig figs like the given value (0.063 = 2 sig figs).

Atomic Mass (He): 4.0026 g/mol

 0.063 moles He            4.0026 grams
----------------------------  x  --------------------------  =  0.2521638 = 0.25 grams He
                                               1 mole

Taking into account the scientific notation, you obtain:

Scientific notation is a quick way to represent a number using powers of base ten and the numbers are written as a product:

a×10ⁿ

where:

You want to subtract two numbers in scientific notation. It should be noted that when the numbers to be added do not have the same base 10 exponent, the base 10 power with the highest exponent must be found.

Then all the values ​​are expressed as a function of the base 10 exponent with the highest exponent.

Taking the quantities to the same exponent, all you have to do is substract what was previously called the number "a". In this case:

In this case:

In summary, you obtain:

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