CHEMISTRY HIGH SCHOOL

Choose the letter of the choice that best completes the statement or answers the question. Elements in the same group have the same __________. A. atomic radius
B. energy level of outer electrons
C. nuclear charge
D. number of valence electrons

Answers

Answer 1
Answer: I think the correct answer from the choices listed above is option D. Elements in the same group have the same number of valence electrons. They have the same number of electrons in the outer orbital. They are the electrons that are involved with chemical bonding with other elements.
Answer 2
Answer: Elements in the same group have D. Same number of valence electrons.

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How many grams of Cl are in 535 g of CaCl2?
Which substance yields H+(aq)as the only positive ion in an aqueous solution
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What is the pressure of 64 grams of O2 in a 1L container at a temperature of 10°C?

Answers

So PV=nRT
P=?

We know that:
-V=1L
-R=8.314kPa•L/mol•K
-T=10°C (we need to converse °C in K so 10+273) =283K
For n, we know that we have 64g of O2 and were looking for the quantity of mole in these 64g. 1 mole of O2 is 15.999g so 64g would be 4.0mol ((64g • 1mol)/15.999g) so n=4.0

P•1L= 4.0mol • 8.314kPa•L/mol•K • 283K
P • 1L = 9411
P = 9411/1L
P = 9411kPa

All compounds containing carbon are organic.
a. True
b. False

Answers

False, not all compounds containing carbon is organic rather all organic compounds contain carbon and hydrogen. Some compounds containing carbon are considered to be inorganic like carbon dioxide, carbon tetrachloride and sodium bicarbonate.

Which of the following would not affect the rate of dissolution of salt in a beaker of water?a. stirring the solution
b. increasing the pressure of the solution
c. decreasing the size of the salt particles
d. increasing the temperature of the solution

Answers

The following which would not affect the rate of dissolution of salt in a beaker of water is:

  • B. increasing the pressure of the solution

The dissolution of salt in a beaker of water increases when an external force stirs it which makes it move from its initial position to a new position.

As a result of this, we can see that if there is a decrease in the size of salt in the beaker of water, there would also be a change in the dissolution of salt in the water.

However, increasing the pressure of the solution would not affect the rate of dissolution of salt in the beaker of water.

Therefore, the correct answer is option B

Read more here:

brainly.com/question/1302627

Answer: Option (b) is the correct answer.

Explanation:

When we stir a solution then its particles start to move from their initial position leading to more number of collisions between them.

As a result, rate of dissolution increases with stirring.

When we increase the pressure then no change in dissolution occurs because in liquids and solids pressure does not play any role is solubility or dissolution.

When we decrease the size of solute particles then there occurs an increase in surface area of solute. Hence, due to this more number of solute particles are able to come in contact with the solvent.

This will lead to more number of collisions. Therefore, rate of dissolution will increase.

Also, when we increase the temperature then molecules of solution will gain kinetic energy leading to more number of collisions which will eventually lead to increase in rate of dissolution.

Thus, we can conclude that out of the given options increasing the pressure of the solution would not affect the rate of dissolution of salt in a beaker of water.

Which of the following statements holds true for a chemical change?A. In a chemical change, no new substance is formed
B. In a chemical change, a substance changes its phase
C. In a chemical change, the molecular structure of a substance changes
D. In a chemical change, one substance dissolves into another

Answers

Answer : The correct option is C.

Explanation :

Chemical change : It is defined as a change in which a new compounds are formed by the chemical reaction. Changes occurs in their chemical composition and properties.

The molecular structure of a substance changes in a chemical reaction is a chemical change.

  • Change in molecular structure means that there is a breaking and formation of bonds in a molecule.

The example of chemical change in terms of change in molecular structure is the reaction of hydrogen with oxygen.

The reaction of hydrogen with oxygen is,

H_2(g)+O_2(g)\rightarrow 2H_2O(l)

In this reaction, the H-H bond is break and O-H bond is form.
c. in a chemical change the molecular structure changes.

Why is it preferable to use Am in smoke detector?Low stable and highly reactive
High stability over long time and source need not be replaced
High penetration and high ionization
A good source of beta radiation and has a half-life of 432 years

Answers

Answer:

Ionization smoke detectors use americium as a source of alpha particles. Alpha particles from the americium source ionize air molecules. This makes some particles positively charged and some negatively charged. ... Because of this shielding, the smoke detector poses no radiation health risk when they are properly handled.

Explanation:

Hope this helped! :D

2KClO3 2KCl + 3O2In the reaction represented by this equation, two moles of KClO3 decompose to form 5 moles of product.

True
False

Answers

True, because most chemical reactions have more moles but not really.
Also that they decompose better. "not really"
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Pleaseeeeeeeeeeeeee please helpYou have learned that the atomic number of a chemical is the number of protons found in the nucleus. Atomic numbers can be used to find the number of neutrons and electrons in an atom. In this project, you will practice atomic mass and atomic mass number calculation as well as fill out a chart using the periodic table. Don’t forget to read through the rubric below, so you will know what you will be graded on. When you are ready, upload it replacing the “Lastname” in the saved document name with your last name. Part I: The atomic number of the sodium atom is 11. The atomic mass number can be estimated by rounding the atomic mass to 23. From this information, you can find the number of neutrons: 11 protons plus how many neutrons equals a mass number of 23? The number of neutrons would have to be the difference between 23 and 11, which is 12. This fact can be restated this way: 11 protons plus 12 neutrons equals a mass number of 23. For every proton in the nucleus, an electron revolves around the nucleus. Since 11 protons are in sodium, 11 electrons must be in sodium. Using this information and the Periodic Table from lesson titled Periodic Table fill in the chart below. Element Atomic Number Atomic Mass How many neutrons? How many electrons? How many protons? Sodium 11 23 12 11 11 Chlorine Carbon Lead Iron Magnesium Uranium Cobalt Calcium Platinum Phosphorus