20. At STP, an element that is a solid and a
good conductor of heat and electricity
could have an electron configuration of
(1) 2-7
(2) 2-8-8
(3) 2-8-5
(4) 2-8-18-2
20

Answer: if it’s a multiple choice then it should be swing dances

Explanation:While the majority of swing dances began in African American communities as vernacular African American dances, some influenced swing-era dances, like Balboa, developed outside of these communities.

Answer:

macromolecules

Explanation:

Polymer is composed of molecules called macromolecules that have multiple of simpler chemical units called monomers.

Answer:

320 gm

Explanation:

4 Fe + 3 O2 ----> 2 Fe2O3 How many moles of iron(III) oxide, Fe2O3 , will be produced if 4 moles of iron, Fe, are consumed

for every 4 moles of Fe, 2 moles of Fe2O3 are produced.

Fe2O3 has a molar mass of (56 X 2) + (16 X 3) = 112 + 48 =160

160 X 2 =320 gm

[tex]\\ \sf\longmapsto H_2+Br_2\longrightarrow HBr[/tex]

[tex]\\ \sf\longmapsto H_2+Br_2\longrightarrow 2HBr[/tex]

On reactant side:-

On products side

The balanced chemical equation for the synthesis of hydrogen bromide is [tex]\rm H_2\;+\;Br_2\;\rightarrow\;2\;HBr[/tex].

The balanced chemical equation has been given as the reaction in which the number of atoms for each element on the product and the reactant side is equal.

The HBr has been formed with the reaction of the hydrogen and the bromine. The balanced chemical equation for the reaction has been:

[tex]\rm H_2\;+\;Br_2\;\rightarrow\;2\;HBr[/tex]

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Answer:

A

Explanation:

B) pollution doesn't affect water

C) Air pollution makes carbon dioxide

D) air pollution does not affect temperature

Work required = 30J

This is because work = F * x

F (Newton's force) = 3N

x (car moved) = 10m

Work = 3 * 10 = 30J

[tex] \large \text{Answer} \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ \\ [/tex]

1.ans: observations, questions, hypothesis, methods and results are the five components of scientific method.

2.ans: written account of object.

3.ans: sry I didn't get

hope my 2 answers can help you ࿐❤

Answer:

1) Sience involves six kinds of components:

• Problems

• Attitudes

• Methods

• Activities

• Conclusions

• Effects

2) Knowledge is information or information that is known or realized by someone.

3) Science form:

• Direct knowledge (direct)

• Indirect knowledge (mediated)

• Sensory knowledge (perception)

• Conceptual knowledge (conceptual)

• Particular knowledge (special)

• Universal knowledge (universal)

Explanation:

I hope this help :)

Answer:

419 grams of CO are needed.

Explanation:

Answer:

Non Metal atoms gain electrons and form negative ion, called anions

Answer:

force i think

Explanation:

Answer:

4.6 grams CuCl2

Explanation:

Since molarity is a representation of moles per liter, we first want to convert 450. mL to liters:

450. mL * 1 L/1000 mL = 0.450 L

Now, we can use this number and the molarity to figure out the answer:

0.075 M means that for every liter, there is 0.075 moles of CuCl2.  Thus, we can multiply the amount of moles per liter by the number of liters of solution.

0.075 moles/1 L * 0.450 L = 0.03375 moles

Then, we need to round this to the appropriate number of significant figures, which gives us:  

0.034 moles CuCl2

Next, we can find the grams of CuCl2.  To do this, we first need to find the molar mass of CuCl2.  The molar mass of Cu is 63.546 g/mol and the molar mass of Cl is 35.453 g/mol, so the molar mass of CuCl2 is as follows:

(1 Cu * 63.546) + (2 Cl * 35.453) = 134.45 g/mol CuCl2

Now, we can multiply the grams per mole by the number of moles of CuCl2 in our solution:

134.45 g/mol * 0.034 moles = 4.5713 grams = 4.6 grams CuCl2, rounded to the appropriate significant figures.

Answer:

Exothermic

Explanation:

Combustion reactions are almost always exothermic because it is an oxidation reaction that produces heat and in this case it would be considered to be exothermic but there are few cases in which it would be considered endothermic. Combustion of Nitrogen is endothermic because Δ  is positive despite being a combustion reaction.

Answer:

B and C

Explanation:

A. Their particles are held together by chemical bonds.

This option is incorrect for both compounds and mixtures. It is only true for Compounds.

B. They are made up of more than one type of atom.

This is correct. Both compounds and mixtures consists of different atoms of elements.

C. They can be separated into two or more elements.

This option is correct. Compounds are broken down into elements through chemical means.

D. Their particles all have the same chemical formula.

This is wrong. Mixtures do not have a chemical formula

Answer:

hm

Explanation:

Answer:

Any polar substance

Explanation:

We know that non polar substances wont dissolve in water because they do not react properly with water molecules, any polar substance would dissolve in water and float in oil.

An unknown substance dissolves in water but separates and floats in oil is any polar substance.

Polar substance are defined as those whose bonding with atoms like nitrogen, oxygen, or sulfur has resulted in discrete positive and negative charge areas.

It can also be defined as an electrical pole is typically created when a molecule has more positive charges on one end than negative charges on the other, forming an electrical pole.

Non polar substances are defined as a molecule that lacks charges at the ends because its electrons are evenly distributed and those that cancel one another out symmetrically.

It is can also be defined as in covalent compounds, there is no change in electronegativity.

Thus, an unknown substance dissolves in water but separates and floats in oil is any polar substance.

To learn more about polar substances, refer to the link below:

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Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

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

From the question

mass = 13 g

density = 19.3 g/cm³

We have

[tex]volume = \frac{13}{19.3} \\ = 0.673575...[/tex]

We have the final answer as

Hope this helps you

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take a few cups of water in a pan and and heat it on a gas burner . the hot water , add some dark brown mixture . then add sugar and milk. sugar is a solute which dissolves in hot water to form a solution . after boiling put some more time , mixture is filtered through a tea - strainer . the prepared tea passes through the tiny holes of the tea - strainer and collects as of filtrate in the cup placed below. the used tea - leaves , being isoluble , collect as a Residue in the the tea - strainer .

〽hope it helps you ✅

Answer:

0.393701

Explanation:

The number of silicon atoms in atypical computer chips(0.001g of silicon) is 2.14 × 10¹⁹ atoms

The atomic mass of silicon = 28.0855 amu

Using the mole concept that 1 mole = 6.022  × 10²³.

This number is called the Avogadro's number.

Therefore,

1 mole /  28.0855g  of silicon contains 6.022  × 10²³ atoms of silicon

0.001 g will contain ? atoms of silicon

cross multiply

number of atoms of silicon = 6.022  × 10²³ × 0.001 / 28.0855

number of atoms of silicon = 6.022 × 10²⁰ / 28.0855

number of atoms of silicon = 2.14 × 10¹⁹ atoms

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Answer:

Explanation:

You have given the exact definition of what an atom is. It is the smallest entity that has all the same properties as a bunch of atoms put together.

:::: Answer ::::

The chemist is most likely investigating Gay Lussac's law. To study the changes in temperature affect the pressure of the gas when a fixed amount of gas is heated in a sealed glass container. Therefore, option (D) is correct.

Gay-Lussac's law states that when the volume of the gas is kept constant the pressure of a gas is directly proportional to the absolute temperature.

The mathematical expression of Gay Lussca's law can be written as follows:

P/T = k

It can be also represented as the pressure being directly proportional to the temperature of the gas.

P ∝ T                    (where V volume of gas is constant)

or

[tex]\frac{P_1}{T_1} =\frac{P_2}{T_2}[/tex]

Where P₁ and T₁ are the initial temperature and pressure of the gas. The P₂ and T₂ are the final temperature and pressure of the gas.

As the container is sealed on heating the volume of the gas will not change.  On increasing the temperature the molecules of the gas acquire more and more kinetic energy. So the pressure of the gas will increase.

Therefore, the chemist is investing the Gay-Lussac's law by noticing how changes in temperature affect the pressure of the gas.

Learn more about Gay Lussac's law, here:

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Answer:

H2SO4 + 2KOH + K2SO4 + 2H2O

Explanation:

there are 2 potassium atoms on the left side so gotta balance that and 2 for the H in the KOH so we have to add a 2 for the hydrogen in H2O..I hope this is useful..

Answer:

(Hope this helps can I pls have brainlist (crown)☺️)

Explanation:

Glucose is the most common form of sugar in the blood and the body's primary source of energy. Glucose is derived from the meals we eat or produced by the body from other chemicals. The circulation transports glucose to the cells. Several hormones, including insulin, regulate blood glucose levels.

a simple sugar that is a component of many carbohydrates and is a vital source of energy in living things.

Blood sugar, often known as glucose, is the most common sugar present in the body. It is your body's major source of energy and comes from the food you eat. Glucose is carried by your blood to all of your body's cells, where it is used for energy.

When the student adds 50 mL of distilled water to each beaker, CaCO3 will not dissolve in water while AgNO3 will dissolve completely in water.

We have to recall that according to the solubility rules, the carbonates of group two elements are insoluble in water. The solubility rules offer a convenient way of predicting the solubility of a compound in water.

When the student adds 50 mL of distilled water to each beaker, CaCO3 will not dissolve in water while AgNO3 will dissolve completely in water. This is because,  the carbonates of group two elements are insoluble in water.

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Answer:

Gravity causes an object to fall to Earth when dropped. When the egg hits the ground with a given force, the ground exerts the same force back on the egg. If too large a force is delivered to the egg shell, the egg will crack.

Explanation: