Which of these statements are true? Select all that apply. The Delta.Hf for Br2(I) is 0 kJ/mol. The Delta.Hf for He(I) is 0 kJ/mol. The Delta.Hf for Hg(I) is 0 kJ/mol. The Delta.Hf for Cl2(g) is 0 kJ/mol. The Delta.Hf for N2(I) is 0 kJ/mol. CORRECT ANSWER IS A, C, AND D.

Answer:

H2 and O2

Explanation:

A coffee cup calorimeter is basically a type of calorimeter that operates at constant pressure. The heat measured in the calorimeter is equal to the change in enthalpy of the reaction.

This type of calorimeter is apt for reactions involving solutions where there is little or no change in volume.

It is not generally applicable to gas phase reactions such as the reaction between H2 and O2.

Answer:

You will not measure the enthalpy of the reaction of

✔ H2 and O2

in the coffee cup calorimeter because this reaction involves gases. Instead, you will use a well-known published value.

C. H2 and O2

Is Correct

Answer:

YES!!!

Explanation:

Strong acids and strong bases are both strong electrolytes. In contrast, only a fraction of the molecules of weak acids and weak bases react with water to produce ions, so weak acids and weak bases are also weak electrolytes.

Answer:

I think no. 4

Explanation:

It is true that Earth’s orbit is not a perfect circle. It is slightly elongated, so that during part of the year, Earth is closer to the Sun than at other times. However, in the Northern Hemisphere, we are having winter when Earth is closest to the Sun and summer when it is farthest away!

There is a completely different reason for Earth's seasons.

Earth's axis is an imaginary pole going right through the center of Earth from "top" to "bottom." Earth spins around this pole, making one complete turn each day. That is why we have day and night, and why every part of Earth's surface gets some of each.

Earth has seasons because its axis doesn't stand up straight

(to be clear I just copied it from some resources)

Answer:

c i took the text

Explanation:

Answer:

1100L.

Explanation:

Answer:

The amount of heat required is 4681.6 J.

Explanation:

mass, m = 16 g = 0.016 kg

initial temperature, T = 5 C

final temperature, T' = 75 C

specific heat, c = 4.18 J/g C

The amount of heat required is

H = m c (T'- T)

H = 16 x 4.18 x (75 - 5)

H = 4681.6 J

Answer:

Percent Yield = 80%

Explanation:

Percent yield of a reaction is defined as one hundred times the ratio between the actual yield and the theoretical yield. That is:

Percent yield = Actual Yield / Theoretical Yield * 100

Where theoretical yield of CaHPO4 is 10g and actual yield is 8g

Replacing:

Percent yield = 8g / 10g * 100

Answer:

I think its "sunspots"

Explanation:

Answer:

Just add a plenty of dots in the first one and very few dots in the second one

An area with high population density will have many dots while areas will low population density will have few dots when using dots to illustrate population density.

Population density is the ratio of the total number of organisms found in a given area to the total of the area of that place or habitat.

An area with high population density indicates that more organised ate found per unit area than an area with low population density.

Therefore, using dots to illustrate population density, an area with high population density will have plenty dots while areas will low population density will have few dots scattered over.

Learn more about population density at: https://brainly.com/question/13902749

Answer: Atoms with 11 protons, 10 neutrons and 11 electrons belong to the same element with 11 protons, 12 neutrons and 11 electrons.

Explanation:

Elements that contain same number of valence electrons belong to the same group. This is because they will have same reactivity (or properties) due to which they lie in the same group.

For example, element with 11 protons, 10 neutrons and 11 electrons is same as the element with 11 protons, 12 neutrons and 11 electrons.

Hence, both these atoms belong to the same element.

Thus, we can conclude that atoms with 11 protons, 10 neutrons and 11 electrons belong to the same element with 11 protons, 12 neutrons and 11 electrons.

Answer:

Solution :

Lithium

Z = 3

P = 3

E = 3 = (2, 1) p=3

A = 7 n=4

P + n = A

3 + n = 7

N = 4



Carbon

Z = 6

P = 6

E = 6 = (2, 4) p=6

A = 12 n=6

P + n = A

6 + n = 12

N = 6

Antoine Lavoisier is known as the "father of modern chemistry” because he first organized all known elements into four different groups.

Antoine Lavoisier made many different and important discoveries in chemistry. He also established water as combination of Hydrogen and Oxygen and that is the very basic beginning of chemistry. The contemporary naming system for chemical compounds is also invented by him. Modern system of chemical nomenclature was the first co-authored by Antoine Lavoisier. He also formulated the law of conservation of mass in chemistry. He has been known as the "Father of Modern Chemistry" because of his brilliant and most important impacts on the history of chemistry.​

Therefore, Antoine Lavoisier is known as the "father of modern chemistry” because he first organized all known elements into four different groups.

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Answer:

The volume of 55 grams of BF₃ is 18.1664 L.

Explanation:

If the molar mass of compound BF₃ is 67.81 [tex]\frac{grams}{mole}[/tex], then the number of moles 55 grams of compound contains is calculated as:

[tex]55 grams* \frac{1 mole}{67.81 grams} = 0.811 moles[/tex]

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

Then it is possible to apply the following rule of three: if by definition of STP 1 mole of a compound occupies 22.4 L, 0.811 moles of the compound occupies how much volume?

[tex]volume=\frac{0.811 moles* 22.4 L}{1 mole}[/tex]

volume= 18.1664 L

The volume of 55 grams of BF₃ is 18.1664 L.

Answer:

37800KJ

Explanation:

Answer:

B

Explanation:

)When iron rusts in air, iron(III) oxide is produced. How many moles of oxygen will react

with 2.4 mol of iron ?

B)1.8 mol

Answer:

[tex] \small \sf \fbox{Physical Change}[/tex]

Explanation:

Crushing a mineral into powder is a physical change.

Answer:

25 possibly

Explanation:

I'm not too sure about this, but sodium oxide is Na2O, 2 sodium and 1 oxygen, so 12.5g * 2 is 25

If someone else comes up with a more convincing argument listen to them

Answer:

That is, a pH meter is useful in detecting or knowing the acidity (due to ions) or alkalinity (due to ions) of a solution. Thus, we can conclude that out of the given options it is true about a pH meter that it can be used in any acid-base titration

Answer: D. It can be used in any acid-base titration.

Explanation:

Answer:

A

Explanation:

Answer:

Antoine Lavoisier and Johann Wolfang Döbereiner organized the elements based on properties such as how the elements reacts or whether they are solid or liquid.

Explanation:

The periodic table of the elements as we have it today was developed as a result of the work of several notable centuries who lived centuries apart, all of who made notable contributions to development of the modern periodic table in use today.

In 1789, Antoine Lavoisier, a French Chemist provided a definition of elemets which he defined as a substance whose smallest units cannot be broken down into a simpler substance. He further grouped the elements into two as metals and nonmetals.

In 1829, German physicist Johann Wolfang Döbereiner arranged elements in groups of three in increasing order of atomic weight and called them triads. His arrangement owasf elements into triads was based on his observation of similarities in physical and chemical properties of certain elements.

John Newlands, a British Chemist was the first to arrange the elements into a periodic table with increasing order of atomic masses.

In 1869, Russian chemist Dmitri Mendeleev developed a periodic table which provided a framework the modern periodic table. He arranged the elements according to their atomic weight, leaving gaps for elements that were yet to be discovered.

The modern periodic table arranges elements based on increasing atomic number.

Answer:

The Eurasian plate(another major plate), the Aegean sea plate and the Anatolian plate share the north border. The Antarctic plate that contributes to the south of the African plate, is also a major plate.

Answer:Electronegativity, symbolized as χ, is the tendency of an atom to attract shared electrons (or electron density) to itself.    

Explanation:

Answer:

Explanation:

The correct answer is cesium

Because If you look at the electronegativities of just Lithium and Cesium then you would notice that the shielding effect is more prevalent in Cesium, thereby reducing the electronegativity and affecting the reduction potential

Answer:

HFusion*mass + Spec.Heat*mass*ΔT + HVap*mass

80cal/g*50.0g + 1.00cal/g°C*50.0g*(100°C-0°C) + 540cal/g*50g

3.60x10⁵cal

Explanation:

Using the HFusion we can find the heat needed to convert the ice to liquid water.

With specific heat capacity we can find the heat needed to increase the temperature of water from 0 to 100°C.

With HVap we can find the heat to convert the liquid water into steam.

The equations are:

Computing the values:

36000cal =

Answer:

Acids react with most metals to form a salt and hydrogen gas. As discussed previously, metals that are more active than acids can undergo a single displacement reaction. For example, zinc metal reacts with hydrochloric acid, producing zinc chloride and hydrogen gas.

Explanation: