Write a chemical equation of Dr. Jeff's demonstration using a battery to light steel wool on fire. The battery is used to allow a current to travel through the steel wool, thus heating it. Steel wood is made from iron (Fe).

Answer:

yes

explanation:

yes because when the velocity is low, all the energy is low and nothing can't do nothing without energy

Answer:

Weaker

Explanation:

Since the charges on nucleus and electron are opposite in nature, an attractive force exists between them. It is true in generally, that when objects are made to move closer together in the direction of an attractive force, potential energy decreases (and increases whenever attracting objects are force to move apart).

Here, we are required to determine if the attraction or repulsion grow weaker or stronger.

First, we must establish scenarios when there can be attraction and ones where there can be repulsion.

By the law guiding electric charges; In electrical interactions:

Like poles repel while Unlike poles attract.

Ultimately, when an electron gets closer to the nucleus, the attraction force will grow stronger due to the reduced distance between the electron and the nucleus.

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Answer:

5. Element J has the highest atomic number

6. Elements G and L have the same number of electrons in their outermost shell.

Explanation:

The periodic table of elements is a table which shows the arrangement of the elements in the order of increasing atomic number. Starting from the topmost left-hand side of the table where the element with the least atomic number is placed, and going across the table from left to right and down to the lowest point to the right of the table, where the element with the highest atomic number is located, the atomic number of elements progressively increases.

Looking at the table, it can be seen that the element J is found at the lowest point to the right of the table. Therefore, element J has the highest atomic atomic number.

6. In the periodic table, elements are arranged into groups and periods. The groups are the columns while the periods are the rows. Elements in the same column or group have the same number of electrons in their outermost shell. Therefore, element G and L have the same number of electrons in their outermost shell.

Answer:

Examples of measured numbers: The diameter of a coin, such as 10.2 mm. The weight of an object, such as 8.887 grams. The length of a pen, such as 12 cm.

Explanation:

Answer:

It completely depends on what you are measuring, what instrument you are using, and the uncertainty associated with your measurement.

Explanation:

When expressing a measurement, there is always going to be a part that you know, and a part that you guess. They both make up known numbers collectively called significant figures (commonly shortened to "sig figs"). For instance, imagine you are measuring the length of a pencil. Let's say it is a typical ruler with divisions of 0.1 cm (picture for reference). You measure the pencil, and to your eyes it looks like it is about 9 cm and 5 small tick marks (so, 0.5 cm), so we'll call that 9.5 cm. Now, this is a known value, so you are certain that it is a least 9.5 cm. However, it may be true that there is one more decimal place that can be known. The general rule is that you want to add one more uncertain digit to the rightmost side of the number, and how many digits depends on the divisions of the instrument. Our ruler has divisions of 0.1 cm (the small tick marks), and so we will go one more place out, and add another digit. Now, let's say our eyes are pretty good, so let's say it's 9.5 cm, and then add that one uncertain digit, a 0 to the smallest division of 0.1, so, 0.10. The final measurement we record is 9.50 cm. Now, it may seem like we are simply guessing or even being unreasonable in our assessment of how long this pencil is. I can promise you that not knowing the actual measurement of this pencil will not make a spaceship crash because of a specification that was not the "right measurement". For those life-or-death measurements, much more precise measurement machines are used; this is just a pencil. Also, it would be unreasonable to say that it is 9.500000 cm or 9.500001 cm. We do not have that kind of certainty with this ruler, only divisions of 0.1 cm, so we can only estimate out to one more decimal place.

In short, find the smallest division of a ruler or whatever device (like a chemical beaker) you are using, and then add one uncertain digit to the end of that. If it's 0.1 cm, then add one digit to that. (example: 5.6 --> 5.63; 3 because that is what it looks like on the ruler). If it's 1 cm, then add an extra .1, so the measurement is 1.1 cm. And of course, it's not always cm you are using, that was just an example. Best of luck!

Answer:

278.1g/mol

Explanation:

To find the molar mass of the given compound, we must know the atomic mass of the elements within the compound.

Atomic mass of Mg = 24.3g/mol

Atomic mass of I  = 126.9g/mol

So;

  Molar mass  = 24.3 + 2(126.9) = 278.1g/mol

The molar mass of the compound is  278.1g/mol

Answer:

protozoan

Explanation:

An animal - like unicellular protist is called a protozoan. Such organisms shows similarities with animals.

Sample left = 6.25 g

The percentage = 6.25%

Given

t1/2 = half-life = 3.8 days

t = decay time = 15.2 days

No = initial sample = 100 g

Required

Nt = final sample left

The percentage

Solution

General formulas used in decay:  

[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]

Input the value :

[tex]\tt N_t=100.\dfrac{1}{2}^{15.2/3.8}\\\\N_t=100.\dfrac{1}{2}^4\\\\N_t=6.25~g[/tex]

The percentage : Nt/No

6.25 : 100 = 6.25%

It attempts to explain the idea that:C. energy is quantized

Answer:

c = 0.898 J/g.°C

Explanation:

1) Given data:

Mass of water = 23.0 g

Initial temperature = 25.4°C

Final temperature = 42.8° C

Heat absorbed = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

Specific heat capacity of water is 4.18 J/g°C

ΔT = 42.8°C - 25.4°C

ΔT = 17.4°C

Q = 23.0 g ×  × 4.18 J/g°C × 17.4°C

Q = 1672.84 j

2) Given data:

Mass of metal = 120.7 g

Initial temperature = 90.5°C

Final temperature = 25.7 ° C

Heat released = 7020 J

Specific heat capacity of metal = ?

Solution:

Formula:

Q = m.c. ΔT

Q = amount of heat absorbed or released

m = mass of given substance

c = specific heat capacity of substance

ΔT = change in temperature

ΔT = 25.7°C - 90.5°C

ΔT = -64.8°C

7020 J = 120.7 g ×  c ×  -64.8°C

7020 J = -7821.36 g.°C ×  c

c = 7020 J / -7821.36 g.°C

c = 0.898 J/g.°C

Negative sign shows heat is released.

Answer:

470.4N

Explanation:

Given parameters:

Mass of Stephanie  = 48kg

Unknown:

Force she exerts while falling to the ground  = ?

Solution:

The force she exerts is her weight;

  Weight  = mass x acceleration due to gravity

  Now insert the parameters ands solve ;

  Weight  = 48 x 9.8 = 470.4N

Answer:

2.8g/cm³

Explanation:

Given parameters:

Mass of cube = 42g

Volume of cube  = 15cm³

Unknown:

Density of the cube  = ?

Solution:

Density is defined as the mass per unit volume of a substance. It is mathematically expressed as:

 Density  = [tex]\frac{mass}{volume}[/tex]  

So;

 Density  = [tex]\frac{42}{15}[/tex]   = 2.8g/cm³

Answer:

Water can be used as the thermometric liquid. It expands and contracts with temperature so it can be used. It's just not a very good choice because: It's thermal expansion is not very large compared to other liquids like mercury.

Explanation:

Hope this help

Answer:

B. A carbon monoxide molecule(CO)

Explanation:

CO is polar because oxygen is more electronegative than carbon, so it gives oxygen a partial negative charge and carbon and partial positive charge. This causes a net dipole moment. CO2 is linear with no net dipole moment because each C-O bond is equal and opposite to each other, so they equal 0, which makes them non polar.

Answer:

1 Sodium, 1 Aluminum (1 Sulfur, 4 Oxygen)

Explanation:

hope that helps

Answer:

C. Equations that separate the oxidation and reduction parts of the reaction.

Explanation:

Redox half-reactions are actually used when balancing redox reactions. It gives the oxidation or reduction reaction components/parts of a redox reaction.  The change in oxidation and reduction states in the substances that are involved in a redox reaction is used to obtain a redox half-reaction.

This redox half-reaction can also be used to explain what takes place in an electrochemical cell; how the anode is undergoing oxidation and how the cathode is undergoing reduction.

Below is an example of a redox half-reaction:

2 Fe³⁺(aq) + 6e⁻ → 2 Fe(s) (Reduction)

3 Mg(s) → 3 Mg²⁺(aq) + 6e⁻ (Oxidation)

Answer:

I'm pretty sure its liver and pancreas

Explanation:

the pancreas delivers the digestive juice to the small intestine through small tubes, your liver makes the digestive juices called the bile that helps digest fats and some vitamins

Answer:

the answer is liver and pancreas

Answer:

3

Explanation:

It is based on empirical evidence

The characteristic of science is that it is based on empirical evidences comprising of a hypothesis.

Hypothesis can be defined as an assumption which is made for the sake of argument . It is an interpretation of a practical condition for which action needs to be taken.It is defined as a tentative assumption which is made to test logical consequences.It is an antecedent clause of a statement which is conditional.

It is constructed before research. There are six types of hypothesis 1)simple hypothesis 2) complex hypothesis 3) directional hypothesis 4)non-directional hypothesis 5) null hypothesis 6)casual hypothesis

The hypothesis should be clear and precise, it must be specific and way of explanation of hypothesis should be simple.

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Answer:

a.the same as

Explanation:

The temperature of each 400mL bucket is about the same as the temperature of the original bucket of paint.

This is because the temperature of the paint inside the bucket is not dependent on the amount of paint present.

Answer:

As Naphthalene undergoes sublimation, we use sublimation process. On condensing naphthalene can be separated.

Answer:

its the sun

Explanation:

Answer shallow ocean

Explanation:

i think

Answer:

723 torr

Explanation:

Using the formula;

P1V1/T1 = P2V2/T2

Where;

P1 = initial pressure (torr)

V1 = initial volume (Litres)

T1 = initial temperature (°C)

P2 = final pressure (torr)

V2 = final volume (L)

T2 = final temperature (°C)

Based on the information provided in this question, V1 = 4.40L, P1 = 555 torr, T1 = 33.0 °C + 273 = 306K, V2 = 3.50 L, P2 = ?, T2 = 44.0 °C + 273 = 317K.

Using the formula above:

555 × 4.4/306 = P2 × 3.5/317

2442/306 = 3.5P2/317

Cross multiply;

2442 × 317 = 306 × 3.5P2

774114 = 1071 P2

P2 = 774114 ÷ 1071

P2 = 722.79

P2 = 723 Torr

A displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule. For instance, when iron is added to a copper sulphate solution, it displaces the copper metal.

A + BC → AC + B

The above equation exists when A is more reactive than B.

A and B have to be either:

Halogens where C indicates a cation.

Different metals wherein C indicates an anion.

[tex]\textsf{what is a displacement reactions?   }[/tex]      

[tex]\large \underbrace{ \underline{ \sf Displacement \: reaction}}[/tex]

The reaction in which more reactive element replace a less reactive element from its compound is called displacement reaction.

Ex:-

[tex]\bold{\large Zn+HCl \longrightarrow ZnCl_2+H_2}[/tex]

Answer:

By far the most abundant volcanic gas is water vapor, which is harmless. However, significant amounts of carbon dioxide, sulfur dioxide, hydrogen sulfide and hydrogen halides can also be emitted from volcanoes.

Answer:

392g

Explanation:

The given compound is;

         Cr₂(SO₄)₃

To find the molar mass, we sum the atomic masses of the elements in the compounds together.

Atomic mass of Cr  = 52

                           S  = 32

                            O  = 16

So;

 Molar mass  = 2(52) + 3[32 + 4(16)]  = 392g/mol

Answer:

D

Explanation:

you should repeat an experiment at least 3 times

Answer:

The chemistry of iron is dominated by the +2 and +3 oxidation states i.e. iron(II) and iron(III) complexes e.g. Fe2+ and Fe3+ complex ions with selected ligands, usually of an octahedral shape, a few tetrahedral iron(III) complexes are mentioned too. The reactions of the aqueous ions iron(II) and iron(III) with ammonia, sodium hydroxide and sodium carbonate are described and explained as are complexes of iron(III) with the chloride ion and cyanide ion.

principal oxidation states of iron, redox reactions of iron, ligand substitution displacement reactions of iron, balanced equations of iron chemistry, formula of iron complex ions, shapes colours of iron complexes, formula of compoundsExplanation:

Answer:

See explanation

Explanation:

A pure liquid has a sharp boiling point. Now we know that the boiling point of water is 100°C.

If Laura begins to heat each liquid with a thermometer inserted into each liquid, the liquid that boils at exactly 100°C is pure water while the rest are solutions.