Please help I’ll give brainlist

Answer:

Atomic radii vary in a predictable way across the periodic table. As can be seen in the figures below, the atomic radius increases from top to bottom in a group, and decreases from left to right across a period. Thus, helium is the smallest element, and francium is the largest.

Answer:

yes, some can

Explanation:

because like salt an other compounds by being decomposed

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.

The reactants in this reaction are sodium and chlorine. Sodium is a soft, silvery-white metal that is highly reactive. Chlorine is a poisonous greenish-yellow gas that has an odor and combines readily with other elements.

This might be the exact question so you might wanna rephrase it but good luck! :)))

A reactant is a substance that undergoes change during a chemical reaction.

A reaction in a chemical experiment is which takes place when there are mixtures between two or more reactants.

There are about four types of reactions which are:

Please note that your question is not complete, therefore, i would give you a general overview to help you.

Some examples of reactants include:

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Answer:

2Fe(s) + 3O2(g) --------> 2FeO3(s)

Explanation:

According to the question, a  battery was used  to light the steel wool by bringing the terminals very close together. When  the battery came into contact with the steel wool, current was sent out through the thin wire.  This caused the iron to heat up quite well.

Iron reacts with oxygen under these conditions as follows;

2Fe(s) + 3O2(g) --------> 2FeO3(s)

This is the chemical reaction that occurs when the steel wool is set on fire.

Chemical equation involved in Dr. Jeff's demonstration is

2 Fe+3 O₂[tex]\rightarrow[/tex]2 FeO₃

Battery is a device which helps in conduction of current. When a battery is used to pass a current through  a substance in this case which is steel wool made up of iron it starts getting heated up.

The amount by which substance gets heated up is directly proportional to the current passing through it. As more current is passed through the battery it gets heated more.

During heating, the iron present in the steel wool reacts with oxygen to form iron oxide with iron present in the+3 oxidation state.When the heat exceeds a certain point the steel wool catches fire due to the heat generated. The  heat causes the electrons present in steel wool of iron to move faster and collide with each other  thus generating more heat.

Learn more about effect of heat in chemical reactions:

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Answer:

2. volume

Explanation:

Answer:

volume

Explanation:

Answer:

(c) only solute present

Explanation:

In chemistry, the mole fraction, denoted by X, refers to the number of moles of a substance in a compound/mixture divided by the total number of substances in the same compound or mixture.

In this case, we can say that mole fraction represents the number of solutes to the number of solutes and solvent in the solution i.e. X = nA/nA + nB

Where; nA = number of solutes

nB = number of solvent

X = mole fraction.

Based on this analogy, When the mole fraction of solute is 1, there is only solute present. That is; X = 1 / 1 + 0

X = 1/1 = 1.

Answer:

B. Controlled variables

Explanation:

The Dependent sample t-test compares the mean score of measurements in one group to that of another other group. It mainly used when analyzing comparable sample units as it pairs repeatable observations within a time frame.

Controlled variables are factors that are not tested and remain constant. Some examples of controlled variables are temperature, pressure, volume etc

Answer:

1.55 x 10²⁴ formula units

Explanation:

Given parameters:

Number of moles of CaCl₂   = 2.58moles

Unknown:

Formula units in the compound  = ?

Solution:

To solve this problem, we must understand that;

    1 mole of a substance contains 6.02 x 10²³ formula units

   2.58 moles will contain 2.58 x  6.02 x 10²³ formula units  

                                            = 1.55 x 10²⁴ formula units

Answer:

12 cm³

Explanation:

Always round to the place of the number with the least amount of significant figures.

1.74 and 3.09 have three significant figures. 2.3 has two significant figures. Therefore, the answer will be rounded to two significant figures.

1.74 cm × 2.3 cm × 3.09 cm = 12.36618 -> 12 cm³

(The 3 in the tenths place is less than 5 so drop it and all the numbers to the right of it.)

Hope that helps.

Answer:

Saliva and teeth in this order

Explanation:

Make me BRANLIEST please

Answer:

87% bromine and 13% magnesium

Explanation:

The compound contained 32.0 grams of bromine and 4.9 grams of magnesium.

We need to find its percent composition.

Mass of the sample = mass of bromine + mass of magnesium

= 32 g + 4.9 g

= 36.9  g

Percentage composition of bromine,

[tex]\%=\dfrac{32}{36.9}\times 100\\\\=86.7\\\\=87\%[/tex]

The percentage composition of magnesium,

[tex]\%=\dfrac{4.9}{36.9}\times 100\\\\=13.27\\\\=13\%[/tex]

So, its percent composition is 87% bromine and 13% magnesium.

Answer:

The answer is A.Digital waves can be copied without damaging the audio signal, whereas analog waves cannot

Explanation:

I took AP EX quiz.

Explanation:

The prefix inter- means between, reflecting that interphase takes place between one mitotic (M) phase and the next. Image of the cell cycle. Interphase is composed of the G1 phase (cell growth), followed by the S phase (DNA synthesis), followed by the G2 phase (cell growth).

Explanation:

Different heating process affect the microstructure of the steel in different ways. Thus, imparting different properties to the steel. For example, annealing is done is done to impart softness to steel, hardening is done to hardened the steel( eg: carburizing, nitriding, cyaniding) whereas tempering is done to improve the ductility of the steel.

Steel mainly contains iron and carbon. This percentage of carbon and iron decides the property of the steel. It is the % of carbon which is altered in different heating process that to obtained the desire microstructure in steel.

Answer:

the paper could be burn up

The molecular mass of gas = 44 g/mol

Given

5.6 Liters of gas

11 gram of gas

Required

The molecular mass

Solution

STP = Standart Temperature and Pressure , 1 atm 273 K

At STP , 1 mol gas = 22.4 L

So mol of 5.6 Liters gas :

= 5.6 : 22.4

= 0.25 moles

The molecular mass of gas :

= mass : mol

= 11 g : 0.25 moles

= 44 g/mol

Answer:

Explanation:

1st convert given data into % per 100wt...

Total system mass = 63.0g + 5.90g = 68.9g

%Rb = 63.0g/68.9g x 100% = 91.4% per 100wt

%O  =  5.9g / 68.9g x 100% = 8.6%

Then follow the following sequence of calculations...

% => grams => moles => mole ratio => reduce to smallest whole no ratio => empirical ratio => empirical formula

%Rb = 91.4% => 91.4g/ 85.5g·mol⁻¹ =>1.069mole

%O  =   8.6% =>  8.6g/16g·mol⁻¹ => 0.5375mole

Rb:O => 1.069 : 0.5375

Reduce by dividing by the smaller mole value

1.069/0.5375 : 0.5375/0.5375 => 2 : 1 <=> empirical ratio

∴ Empirical Formula => Rb₂O

Answer:

There are three forces acting on the skateboard. One of these forces is the weight of the rider. Another is the force of gravity on the board itself. The third is the force of the ground pushing up on the skateboard.

Explanation:

1)

2Fe+3Cl2 →2FeCl3

2)

CH4+2O2 → CO2 +2H2O

3)

SnO2+2H2 →2H2O +Sn

4)

2KOH + H2SO4 → K2SO4+2H2O

Answer:

The postulate that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass.

Explanation:

The law of constant composition (or definite proportion) states that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass.

This law implies that irrespective of the source of the sample of the compound or the method by which the sample was prepared, as long as the sample is pure, the elements present in the compound are always combined in a specific ratio by mass. For example, water has the molecular formula H₂O. Irrespective of the water source, for example, tap-water, lake, stream, river or rainfall, each pure sample of water will have the constant composition of 2 atoms of hydrogen to one atom of oxygen.

The given compound exists as XO in nature. Therefore, irrespective of the source or method of preparation, every sample of this compound should have the formula XO. Since the compound prepared by the scientist was XO₂, therefore, the postulate that all pure samples of a particular chemical compound contain the same elements  combined in the same proportion by mass was violated by the scientist. The scientist must have prepared a different compound of the elemental compositions.

Answer:

A. Metalloids.

Explanation:

Metalloids. Metalloids, also called semiconductors, are the elements that border the zigzag line on the periodic table.

Answer:

1.00 g

Explanation:

got it on pex

Answer:

a, u cannot bend rocks

Explanation:

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Answer:

B

Explanation:

Answer:

I think the answer would be B. hope this helps!!

Explanation:

Answer:

0.1139952 is the answer

Explanation: