A student conducting a calorimetry investigation determines a negative ∆H. What does the negative value indicate about the reaction?

A. The reaction synthesized a single product.

B. The reaction was exothermic.

C. The reaction absorbed energy.

D. The reaction involved decomposition.

The elements in the tall columns of the periodic table are called representative elements or main group elements. They exhibit similar chemical properties within their respective groups due to their shared number of valence electrons. The terms "valence elements," "atomic elements," and "period elements" are not commonly used or recognized in the context of the periodic table.

The correct answer is option  A.

The elements in the tall columns of the periodic table are called "A. Representative elements," also known as the "main group elements" or "group A elements." These elements are found in groups 1, 2, and 13 to 18 (excluding the transition metals) on the periodic table.

Representative elements are characterized by having similar chemical properties within their respective groups. This similarity arises from the fact that elements within the same group have the same number of valence electrons, which are the electrons in the outermost energy level of an atom. Valence electrons play a crucial role in determining the chemical behavior and reactivity of an element.

The representative elements include the alkali metals (Group 1), alkaline earth metals (Group 2), boron group (Group 13), carbon group (Group 14), nitrogen group (Group 15), oxygen group (Group 16), halogens (Group 17), and noble gases (Group 18). These elements exhibit a wide range of properties, from highly reactive metals to nonmetals and inert gases.

The term "valence elements" mentioned in option B is not commonly used in the context of the periodic table. Valence electrons are indeed significant in determining chemical properties, but they are not specific to the elements in the tall columns. Valence electrons are found in elements across the periodic table.

"Atomic elements" mentioned in option C is a vague term and does not specifically refer to the elements in the tall columns. All elements on the periodic table are atomic in nature, as they are composed of atoms.

"Period elements" mentioned in option D is not a recognized term in the context of the periodic table.

In conclusion, the elements in the tall columns of the periodic table are known as representative elements or main group elements. These elements exhibit similar chemical properties within their respective groups due to their shared number of valence electrons.

Therefore, from the options provided the correct one is A.

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Answer:

3 ................................

Answer: 3

Explanation:

yes

Answer:

C)1 and 3 only☺️

Explanation:

Answer:

The specific heat of the mineral is 0.1272J/g°C

Explanation:

The sample is given energy to the calorimeter and the sample of water.

The energy released for the sample is equal to the energy absorbed for both the calorimeter and the water:

C(Sample)*m*ΔT = C(Calorimeter)*ΔT + C(water)*m*ΔT

Where C is specific heat

m is mass of the sample and water

And ΔT is change in temperature

C(Sample)*149g*(92.7°C-23.7°C) = 12.8J/K*(23.7°C-20.0°C) + 4.184J/g°C*81.4g*(23.7°C-20.0°C)

C(Sample)*10281g°C = 47.36J + 1260.1J

C(Sample) = 0.1272J/g°C

The specific heat of the mineral is 0.1272J/g°C

The energy released for the sample should be equivalent to the energy absorbed for both the calorimeter and the water:

So,

C(Sample)*m*ΔT = C(Calorimeter)*ΔT + C(water)*m*ΔT

here C is specific heat

m is mass of the sample and water

And ΔT is change in temperature

Now

C(Sample)*149g*(92.7°C-23.7°C) = 12.8J/K*(23.7°C-20.0°C) + 4.184J/g°C*81.4g*(23.7°C-20.0°C)

C(Sample)*10281g°C = 47.36J + 1260.1J

C(Sample) = 0.1272J/g°C

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Answer:

Either 12:12:6 or 6:6:12

Explanation:

If I remember correctly the answer should be 6:6:12

A small pebble sinks in water because its density is greater than the density of water. Density is a measure of how much mass is packed into a given volume. If an object is denser than the liquid it is placed in, it will sink.

When a pebble is dropped into water, the water exerts an upward force called buoyancy. This force opposes the weight of the pebble, and if the pebble is less dense than water, it will experience an upward force greater than its weight and float.

However, if the pebble's density is greater than that of water, the downward force due to its weight will be greater than the upward buoyant force, causing it to sink.

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Answer:

3

Explanation:

It is in the third column or group on the periodic table

Answer:

It is generally arranged by the atomic number

Explanation:

Answer:

2 days.

Explanation:

Answer:

Explanation:

A proton has a mass of approximately 938 MeV/c2, of which the rest mass of its three valence quarks contributes only about 9.4 MeV/c2; much of the remainder can be attributed to the gluons' QCBE.

Answer:

how do I answer without context

Answer:

C is the only reasonable answer.. but this is 6th grade science and I'm in 7th, so I'm pretty sure I'm right

Answer:

chongus because he's the only good one

Answer:

Theoretical yield = 0.1 g

Percent yield = 80%

Explanation:

Given data:

Mass of sodium = 2.3 g

Actual yield of hydrogen = 0.080 g

Theoretical yield = ?

Percent yield = ?

Solution:

Chemical equation:

2Na + 2H₂O    →  H₂ + 2NaOH

Number of moles of sodium:

Number of moles = mass/ molar mass

Number of moles = 2.3 g/ 23 g/mol

Number of moles = 0.1 mol

Now we will compare the moles of sodium with hydrogen to calculate the theoretical yield.

                       Na               :              H₂

                        2                :               1

                     0.1                 :             1/2×0.1 = 0.05 mol

Mass of hydrogen produced:

Mass = number of moles × molar mass

Mass = 0.05 mol × 2 g/mol

Mass = 0.1 g

Percent yield of hydrogen:

Percent yield = actual yield / theoretical yield ×100

Percent yield = 0.08 g/ 0.1 g×100

Percent yield = 0.8×100

Percent yield = 80%

Answer:

Physical Properties

Explanation:

PHYSICAL PROPERTY

Answer:

phycical propertys

Explanation:

jut took the test got it right

Answer:

D. Directly to The Right

Answer:

K

Explanation:

Answer:

37.25

Explanation:

[tex]P_1[/tex] = Initial pressure = [tex]14.8\ \text{atm}[/tex]

[tex]P_2[/tex] = Final pressure = [tex]12.3\ \text{atm}[/tex]

[tex]V_1[/tex] = Initial volume = [tex]23.5\ \text{mL}[/tex]

[tex]V_2[/tex] = Final volume

[tex]T_1[/tex] = Initial temperature = [tex]315\ \text{K}[/tex]

[tex]T_2[/tex] = Final temperature = [tex]415\ \text{K}[/tex]

From ideal gas law we have

[tex]PV=nRT[/tex]

[tex]\Rightarrow PV\propto \dfrac{1}{T}[/tex]

So

[tex]\dfrac{P_1V_1}{T_1}=\dfrac{P_2V_2}{T_2}\\\Rightarrow V_2=\dfrac{P_1V_1T_2}{T_1P_2}\\\Rightarrow V_2=\dfrac{14.8\times 23.5\times 415}{315\times 12.3}\\\Rightarrow V_2=37.25\ \text{mL}[/tex]

The final volume is [tex]37.25\ \text{mL}[/tex]

Answer:

97.95 g/mol

Explanation:

Step 1: Define molar masses

Molar Mass of N - 14.01 g/mol

Molar Mass of H - 1.01 g/mol

Molar Mass of Br - 79.90 g/mol

Step 2: Find amounts of molar masses

1 mol N - 14.01 g/mol

4 mol H - 4.04 g/mol

1 mol Br - 79.90 g/mol

Step 3: Find molar mass of compound

Molar Mass N + 4 Molar Mass H + 1 Molar Mass Br

14.01 g/mol + 4.04 g/mol + 79.90 g/mol

97.95 g/mol

Explanation:

subtract it into 273.15to convert it in to celcius

Answer: 1.9 x 10^4

Explanation:

A dog has a mass of 19 kg. The mass of the dog in grams, expressed in scientific notation, is 1.95 × 10⁴ g.

Mass is the quantity of matter in a physical body. The product of the compound's molar mass and the substance's moles are defined as mass.

Measuring units to determine the size, weight, or quantity of any object. Seven fundamental measurement units are utilized in daily life and across the globe.

These units of measurement are the meter, which is used to measure distance, and the second, which is used to measure. Grams and kilograms are the measuring units that are used to measure the quantity of a solid item.

The mass of the dog in grams is:

1 kilogram = 1000 grams

19.5 kg × (10³ g/1 kg) = 1.95 × 10⁴ g.

Thus, the mass of the dog in grams is 1.95 × 10⁴ g.

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Answer:

Neither

Explanation:

The statements are true for both fusion and fission reactions are the fission is the breaking of a heavy, unstable nucleus into two lighter nuclei, and fusion is the process where two light nuclei join together releasing large amounts of energy. Therefore, option D is correct.

The term fission is defined as when a neutron slam into a larger atom, forcing it to excite and split into two smaller atoms.

Additional neutrons are released, which can set off a chain reaction. A tremendous amount of energy is released when each atom splits.

When a neutron strikes an atom of uranium-235, it splits into two lighter nuclei, krypton and barium.

Both fission and fusion reactions involve the conversion of some mass into energy in order to form a new nucleus or nuclei, which requires some nuclear binding energy.

Thus, option D is correct.

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Answer:

1.186L or 1186mL.

Explanation:

The volume of a 0.290 m NH4I solution that is required to react with 253 ml of a 0.680 m Pb(NO3)2 solution is 1.186 liters or 1186 ml.

Potassium acid phthalate will serve as our primary standard. This is a large molecule (KHC8H4O4) with a molar mass of 204.2 g/mol. Instead of writing the whole formula, we abbreviate it as KHP, where "P" stands for the phthalate ion, C8H4O42-, not for phosphorus. KHP is an acidic substance, with the ionizing hydrogen being set forward in the formula for emphasis. Therefore, KHP is monoprotic and will react with NaOH in a simple 1 to 1 relationship according to the following equation:

Answer:

The law of superposition states that each rock layer is older than the one above it.  So, the relative age of the rock or fossil in the rock is older if it is farther down in the rock layers.

Answer:

It is C

Explanation:

It is because Prokaryotic cells mostly don't have a nucleus.

Answer:

It is C.Eukaryotic cells have nuclei; prokaryotic cells do not

Explanation:

I just watched a video of it.

Answer:

The rest of the food molecule is converted to other carbon molecules. The hawk cannot consume all the parts of the squirrel. It will feed as a carnivore on the fleshy part of its prey. The matter is converted to other carbon molecules

Explanation:

Answer:

0.34 J / g ⁰C

Explanation:

Let the specific heat of metal be s .

heat will be lost by hot metal and gained by water .

heat lost by metal = mass x specific heat x loss of temperature

= 75 x s x ( 99 - 28 ) = 5325 s

heat gained by water = mass x specific heat x gain of temperature

= 145 x 4.18 x ( 28 - 25 ) = 1818.3

heat lost = heat gained

5325 s = 1818.3

s = 0.34 J / g ⁰C

Answer:

On Question 3

Explanation:

try using any type or liquid like water, milk, soda, juice, coffee, tea, beer, or wine or any type and use the following questions by using a measuring cup from the kitchen tooling shelf. Use that to answer the question and see if that helps. your welcome btw