CHAPTER
CHAPTER ASSESSMENT
Understanding Main Ideas (Part A)
In the space at the left, write true if the statement is true; if the statement is false,
change the italicized term to make it true.
1. The overall charge of a formula unit for a compound is never zero.
2. In a crystal lattice, each positive ion is surrounded by negative ions.
3. Delocalized valence electrons are typical of ionic compounds.
4. A sulfate ion contains fewer oxygen atoms than a sulfite ion does.
true
5. Metals tend to be malleable and ductile and to have relatively high
melting points.
6. The more negative the lattice energy is, the stronger is the force of
attraction between the ions of an ionic compound.
7. In naming ionic compounds, the cation is named first.
8. When a metal reacts with a nonmetal, the metal tends to gain electrons.
9. In naming a monatomic anion, the suffix -ide is used.
10. The prefix per- is used in naming the anion with the most oxygen atoms.

Answer: 0.74 moles

Explanation:

The first step is to figure out the chemical formula for calcium phosphate. Since we know that calcium is a metal, this will be an ionic bond. Calcium is written as Ca and has a charge of +2. Phosphate is written as PO4 with a charge of -3. To come up with the subscripts for this formula, cross the charges. That means that you will get [tex]Ca_{3} (PO_{4} )_{2}[/tex].

Next, calculate how many grams one molecule of calcium is. Calcium has an atomic weight of 40, and there are 3 molecules of calcium, so 40 x 3 = 120. Phosphorus has an atomic weight of 31, and there are 2 molecules of phosphorus, so 31 x 2 = 62. Oxygen has an atomic weight of 16, and there are 8 molecules of oxygen, so 16 x 8 = 128. Adding all of those together gives you 310 g.

Now, using stoichiometry, we can figure out the question. We know that there are 230 grams. We also know that one mole weighs 310 g. If you divide 230 by 310, you will get your answer, which is 0.74 moles.

Answer:

The energy required is 158 J

Explanation:

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

When the heat added or removed from a substance causes a change in temperature in it without affecting its molecular structure, this heat is called sensible heat.

In other words, when a system absorbs (or gives up) a certain amount of heat, it can happen that it experiences a change in its temperature, which implies sensible heat.

The equation that allows calculating heat exchanges is:

Q = c * m * ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

In this case:

Replacing:

Q= 0.79 [tex]\frac{J}{g*C}[/tex] *10 g* 20 C

Solving:

Q= 158 J

The energy required is 158 J

Answer:

The volume will decrease and the balloons will be smaller

Agricultural research careers would a student studying biotechnology most likely pursue. Therefore, option C is correct.

The United States Department of Agriculture's main internal research organization is the Agricultural Research Service. One of the four organizations in the USDA's mission area for research, education, and economics is ARS.

A wide definition of agricultural research is any research activity that aims to increase crop output and quality through genetic improvement, improved plant protection, irrigation, storage techniques, farm mechanization, effective marketing, and better resource management.

Agricultural research's main goals are to advance knowledge and advance technology. It deepens comprehension of the linkages and interconnectedness between farming communities and production systems.

Thus, option C is correct.

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Complete question is;

When solid materials are heated.the heat absorbed/added to the materials caused the materials to change its form from?

Answer:

From solid to liquid

Explanation:

When we heat solid materials, the heat causes the forces of attraction between the molecules to become weaker and as such, the material becomes more loose than it was in the solid state. As a result, the material now becomes a liquid because the molecules now have lesser forces of attraction and are a bit loose.

1.497 mol Ir

Math

Pre-Algebra

Order of Operations: BPEMDAS

Chemistry

Atomic Structure

Stoichiometry

Step 1: Define

287.7 g Ir

Step 2: Identify Conversions

[PT] Molar Mass of Ir - 192.22 g/mol

Step 3: Convert

Step 4: Check

Follow sig fig rules and round. We are given 4 sig figs.

1.49672 mol Ir ≈ 1.497 mol Ir

Answer:

[tex]\boxed {\boxed {\sf About \ 1.497 \ mol \ Ir }}[/tex]

Explanation:

To convert from grams to moles, we must the molar mass of iridium, which can be found on the Periodic Table.

Use the molar mass as a ratio.

[tex]\frac{ 192.22 \ g \ Ir}{ 1 \ mol \ Ir}[/tex]

Multiply by the given number of grams: 287.7

[tex]287.7 \ g Ir *\frac{ 192.22 \ g \ Ir}{ 1 \ mol \ Ir}[/tex]

Flip the fraction so the grams of Iridium will cancel.

[tex]287.7 \ g Ir *\frac{1 \ mol \ Ir }{ 192.22 \ g \ Ir}[/tex]

[tex]287.7 *\frac{1 \ mol \ Ir }{ 192.22 }[/tex]

[tex]\frac {287.7 \ mol \ Ir }{192.22} \\[/tex]

Divide.

[tex]1.49672251 \ mol \ Ir[/tex]

The original measurement has 4 significant figures, so we must round our answer to 4 sig figs as well. For the answer we calculated, that is the thousandth place.

The 7 in the ten thousandth place tells us to round the 6 up to a 7.

[tex]1.497 \ mol \ Ir[/tex]

There are about 1.497 moles of iridium in 287.7 grams.

Answer:

Emissions produced by burning fossil fuels

Explanation:

these gases decreases the ph level of rain water that makes water acidic

Answer:

Es so es na formula pero te balto la convinasiones de la formula

Answer:

Deciliter = 0.1 L

Explanation:

The options are unit of volume. In order to determine which is greatest, all the options would be converted to liter.

Microliter = 1e-6 L

Mililiter = 0.001 L

Deciliter = 0.1 L

Centiliter = 0.01 L

Among all the options; Deciliter = 0.1 L is the greatest.

Answer:

It's Mass

Explanation: I took the quiz

Have a good day!

Mass is the amount of matter in an object. Therefore, option C is correct.

Mass can be defined as an intrinsic property of a body. mass can be described as the quantity of matter in a body. Different atoms and different particles with the same amount of matter have nonetheless different masses.

Mass can be experimentally measured by the body's inertia, meaning the resistance to acceleration when a net force is applied. The mass determines the strength of its gravitational attraction to other bodies.

The SI base unit of measurement of mass is the kilogram (kg) and it is not the same as weight. Mass is generally determined by measuring the weight using a spring scale, rather than a balance scale and comparing it to known masses.

An object on the Moon will weigh less than it does on Earth due to the lower gravity but still have the same mass. Weight can be defined as a force, while mass is the property that determines the strength of this force.

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Answer:

A. moving

Explanation:

Answer:

Explanation:

mixture of iron filings, sand, and sugar

First Step - Iron Fillings

Use a magnet to separate the iron fillings from the mixture. Due to magnetic properties of the iron fillings, the magnets would attract the iron fillings and separate it from the mixture.

Second step - Sand

Place the sand and sugar mixture in water. The sugar would dissolve in water and the sand easily separated by filtration.

Third step - Sugar and Sugar water

Boil the sugar water to remove the water and place in the refrigerator for crystallization of the sugar.

Answer:

option b is correct

Explanation:

Metals are particularly good conductors of heat because their particles are very closely packed so the vibrations are passed on very quickly. They also contain large numbers of free electrons. These drift slowly through the structure, giving metals their strength and other properties. As the metal is heated, the free electrons closest to the heat source are heated. This makes them move faster and they travel through the metal, colliding with both atoms and other electrons. This naturally makes these vibrate faster (or move through the metal faster in the case of collisions with other free electrons). Thus, the heat is passed quickly through the metal.

hope it helps you

please mark me as brainlist

Answer:

Graham's law states that the rate of effusion or of diffusion of a gas is inversely proportional to the square root of its molecular weight. So, rate of diffusion of hydrogen gas is four times faster than oxygen gas.

Explanation:

Answer:

Rate of diffusion of hydrogen is higher than other gases because mass of hydrogen is very small and it diffuses easily.

Explanation:

Answer:

like ground rocks and shells I think.

Explanation:

Answer:

it will have 1 valence electron as its in the first group in the periodic table.

It will lose electrons as its easier.

The charge will be 1+ as it lost 1 .

Answer:

See explanation

Explanation:

A word equation refers to a representation of a chemical process using word rather than appropriate chemical formulae.

Hence, the word equation for photosynthesis is this;

six moles of carbon dioxide + six moles of water -----> one mole of glucose + six moles of oxygen gas

The equation with formulae is;

6CO2 + 6H20 -------> C6H1206 + 6O2

Balanced chemical equation with states;

6CO2(g) + 6H20(l) -------> C6H1206(s) + 6O2(g)

Answer:

wait so dose it acid burn your body I would say hydrogen but I'm probably wrong tell me if I am

Answer:

Heat Capacity = E / T.

- Find the difference in temperature for changes of multiple degrees.

- Add the appropriate units to your answer to give it meaning.

- Know that this equation works for cooling objects as well.

- Know that specific heat refers to the energy needed to raise one gram by one degree.

Answer:

Explanation:

Br- + 2MnO4- + 2H+ → BrO3- + 2MnO2 + H2O

Given

MnO4- + Br- = MnO2 + BrO3-

Required

The half-reaction

Solution

In acidic conditions :

1. Add the coefficient

2. Equalization O atoms (add H₂O) on the O-deficient side.  

3. Equalization H atoms (add H⁺ ) on the H -deficient side.  .  

4. Equalization of charge (add electrons (e) )

5. Equalizing the number of electrons and then adding the two half -reactions together

Oxidation : Br- → BrO3-  

Reduction : MnO4- → MnO2

Br- + 3H2O → BrO3-  

MnO4- → MnO2 + 2H2O

Br- + 3H2O → BrO3- + 6H+  

MnO4- + 4H+ → MnO2 + 2H2O

Br- + 3H2O → BrO3- + 6H+ + 6e-         x1

MnO4- + 4H+ + 3e- → MnO2 + 2H2O x2

Br- + 3H2O → BrO3- + 6H+ + 6e-  

2MnO4- + 8H+ + 6e- → 2MnO2 + 4H2O

Br- + 2MnO4- + 3H2O + 8H+ + 6e- → BrO3- + 2MnO2 + 6H+ + 4H2O + 6e-

Br- + 2MnO4- + 2H+ → BrO3- + 2MnO2 + H2O

Answer:

1. Algae

2. Insects

3. Crayfish

4. Trout

5. Herons

Explanation:

Answer:

id.k sorry

Explanation:

Answer:

b

Explanation:the shell is 2 so ignore the 1s electrons it is only the level 2 electrons that are valence

Answer:

it would be C

Explanation:

Answer: C

Explanation:

both numbers have 2 S.F. so the answer should have 2 too.

Answer:

yes

Explanation:

The correct equation for the decomposition of copper carbonate is:

CuCO3 → CuO + CO2

Answer:

Explanation:

A) 0.150

B) 0.300

C) 0.450

hope it helps:)

Answer:

A. a power source connected to the primary coil

Explanation:

Answer:

the object should be displaced on which the force is applied

Explanation:

HOPE IT HELPS YOU

Answer:

Any characteristic that can be determined without changing the substance's chemical identity. chemical property: Any characteristic that can be determined only by changing a substance's molecular structure

Explanation:

Answer:

A: dependent variable

B: experimental group

C: independent variable

D: control variables

E: control group

Explanation: