Which statement describes the law of conservation of energy?
All systems will exchange matter and energy with their surroundings.
All systems can exchange energy, but not matter, with their surroundings.
Energy cannot be created nor destroyed, but it changes from one form to another.
Energy is destroyed in most chemical reactions when new products are formed.

Answer:

1) actual yield - 2.675 g

Theoretical yield - 4.0539 g

2)a) 41.257 g

b) 0.6857moles

c) 23 g

Explanation:

1)

Theoretical yield is the mass of the product that can obtain from the equation, it is not practical.

Theoretical yield:

Mr of SiO2 - 60

Moles of SiO2 - 2.339/60 = 0.03898 moles

Mr of SiF4 - 104

Mass of SiF4 - 0.03898 * 104 = 4.05392 g

2)

a)

mr of B2H6 - 28

Moles of B2H6 - 36.1/28 = 1.2893 moles

Mr of O2 - 32

Mass of O2 - 32 * 1.2893 = 41.257 g

b)

Moles of B2H6 - 19.2/28 = 0.6857 moles

Stoichiometry 1:1 ratio between B2H6 and H2O

So moles of H2O is 0.6857

c) moles of O2 - 2/24(r.t.p) = 0.083 moles

Mass of B2H6 - 0.083 * 28 = 2.3 g

Answer: Sodium also floats on the surface, but enough heat is given off to melt the sodium (sodium has a lower melting point than lithium and the reaction produces heat faster) and it melts almost at once to form a small silvery ball that dashes around the surface.

Explanation:

Answer:

hydroxide.

Explanation:

Alkali metals are in group 1 of the Periodic Table. They are on the left of the Periodic Table. These are the alkali metals as follows:

When alkali metals react with water they make alkaline solutions, so the universal indicator turns people and they produce hydrogen and a metal hydroxide. When sodium is put in water, the metal floats on the surface it reacts to form sodium hydroxide and hydrogen.

Answer:

It's because it has 2 electrons on its outer ring

Explanation:

It has a -2 ion due to it having 2 more electrons than protons making it an overall negative. It's well known in chemistry that the first ring can only hold 2 electrons while the second and furthermore can hold up to 8. But what happens when you have 9? a new ring starts and it would only contain 1 electron.. In our case here it has 2 more electrons than protons and those 2 electrons are located on the outer ring

It would take 211 hours to plate 28.3 g of silver on a flute.

The equation of the reaction;

Ag^+(aq) + e -----> Ag(s)

We know that 1 F of electricity is required to deposit 107.87 g of Ag. Also 1F = 96500 C

Now;

Since  107.87 g is deposited by 96500 C of electricity

28.3 g is deposited by  28.3 g ×  96500 C/ 107.87 g

= 25317 C

Also;

Q = It

I = current

t = time

25317 C =  2.0 amps × t

t = 25317 C /2.0 amps

t = 12658.5 seconds or 211 hours

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Answer:

Explanation:

Electrolysis equation is:

[tex]Ag1+ + 1e- ------> Ag[/tex]

1 mol of Ag requires 1 mol of electron

1 mol of electron = 96485 C

So,

1 mol of Ag requires 96485 C

let us calculate mol of element deposited:

molar mass of Ag = [tex]107.87 g/mol[/tex]

number of mol of Ag, [tex]n = \frac{mass of Ag}{molar mass of Ag}[/tex]

[tex]n = \frac{28.3}{107.87}\\\\n = 0.2623 mol[/tex]

[tex]total charge = mol of element deposited * charge required for 1 mol\\\\total charge = 0.2623*9.649*10^4\\\\total charge = 2.531*10^4 C[/tex]

Therefore,

[tex]time = \frac{Q}{i}\\\\= \frac{2.531*10^4}{2}\\\\= 1.265*10^4 seconds\\\\= 3.515 hr[/tex]

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Answer:

4.58g

Explanation:

1.) What is the molar mass of CaCI2?

= 110.98 g/mol

2.) Find the mols

[tex]conc = \frac{mol}{volume(l)} [/tex]

conc × volume= mol

0.125 M x 0.33 L = 0.04125mol ( 330mL was converted to "L" by dividing 330 by 1000)

3.) The mass(g)

g= mol x atomic weight

g= 110.98g/mol × 0.04125

= 4.58 g

# NOTE M = mol/L

Answer:

Power Plant = Mitochondria (Mitochondria is the powerhouse of the cell)

City Limits = Cell Membrane (Outer layer of a cell)

City Hall = Nucleus (The nucleus is the control center in a cell)

City Food Processing Plant (Chloroplast process the cells food)

City Plans = Chromosomes (They contain the genetic information about the cell)

Community = Cytoplasm (Mainly process of elimination)

Explanation:

Explanations are in parenthesis

Answer:

a) sodium oxide

b) potassium peroxide

c) Hydrogen chloride

d) form ammonia

e) Calcium nitride

Answer:

There are several different types of tools you could encounter, including project management software, note-taking programs, journals, and day planners. Organization management tools help in sorting out one’s daily responsibilities and being more efficient with time: calendars, to-do lists, mind maps, document storage clouds.

Explanation:

what i know:) hope it helps

Answer:

1. Ionic bonds result from transfer of electrons, but covalent bonds are formed by sharing.

2. Ions are arranged in a three-dimensional array (like crystals). Covalently bonded substances exist as discrete molecular units.

3. Ionic compounds often dissociate into ions in solution, but covalently bonded molecules retain their molecular identity in solution.

Hope this helps :)

Answer:

Extensive or inextinsive and either physical or chemical

The electron configuration for the ion's neutral parent atom is

1s²2s²2p⁶3s²3p⁶4s²

It belongs to group 2 on the periodic table and one of its chemical properties is, it has a density of 1.54 g/cm³

From the question,

The cation has a charge of 2+. This means the neutral atom lost 2 electrons.

From the given electron configuration, the cation has 18 electrons.

Therefore, the neutral atom of ion will have 20 electrons.

∴ The electron configuration for the ion's neutral parent atom is

1s²2s²2p⁶3s²3p⁶4s²

The atom belongs to group 2 on the periodic table.

One chemical property of the parent atom

Its density is 1.54 g/cm³

Hence,  The electron configuration for the ion's neutral parent atom is

1s²2s²2p⁶3s²3p⁶4s²

It belongs to group 2 on the periodic table and one of its chemical properties is, it has a density of 1.54 g/cm³

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Answer:

58.64

Explanation:  You want to use the combined gas law equation (P1*V1)/(n1*T1)=(P2*V2)/(n2*T2). So first cross out what remains constant, so pressure and I assume moles (since it was not mentioned as a change). You want to change the temperature to Kelvin (always) to do work, then you can solve algebraically for the answer! Once you have your answer change it to Celsius since that's what you were asked for.

Hope this helped!

The number of atoms of Hg in 4.5 mole sample has been given as [tex]\rm 2.7099\;\times\;10^2^4[/tex]. Thus, option A is correct.

The number of atoms in a mole of sample has been given by Avogadro number. Avogadro number has been a constant and has been given the value of [tex]\rm 6.023\;\times\;10^2^3[/tex].

The number of atoms in a mole of sample has been given as:

[tex]\rm 1\;mole=\;6.022\;\times\;10^2^3[/tex]

The given sample has been consisted of 4.5 moles of Hg. Thus, the number of atoms in the sample has been given by:

[tex]\rm 1\;mole\;Hg=\;6.022\;\times\;10^2^3\;atoms\\4.5\;mol\;Hg=4.5\;\times\;6.022\;\times\;10^2^3\;atoms\\4.5\;mol\;Hg=27.099\;\times\;10^2^3\;atoms[/tex]

The scientific notation has been the short hand used for writing the numbers. The short hand for atoms in 4.5 moles of Hg has been [tex]\rm 2.7099\;\times\;10^2^4[/tex].

Thus, the number of atoms of Hg in 4.5 mole sample has been given as [tex]\rm 2.7099\;\times\;10^2^4[/tex]. Thus, option A is correct.

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The downside of this is that the longer lasting material is more difficult to break down.

Both natural fibers and synthetic fibers are polymer materials. Polymer materials are materials that are made by the agglomeration of small molecules called monomers.

The natural fibers are less long lasting than the synthetic fibers. The downside of this is that the longer lasting material is more difficult to break down. As a result of these, synthetic fibers lead to environmental pollution problems.

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Answer:

the longer lasting material is more difficult to break down.

Explanation:

Answer:

20

Explanation:

You need 4 times the amount of B, compared to a (there is a 3A:12B which reduces to 1:4), so 4 times 5 is 20.

Hope this helps!

What factors can influence the properties of glass, which include its ability to transmit, reflect, or absorb light, or to be transparent?

Answer · 47 votes

The properties can be influenced by many factors. The most common are the shape of the object, the lighting where the object is located, the environment (colors, shapes, density of other objects, etc.), and the viewing angle of the observer.

Answer:

Sulfur hexafluoride

Explanation:

It is heavier than air that we breathe so it has an opposite effect.

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As we know, Number of protons = Atomic Number

So,

And, Atomic mass = Number of protons + Number of Neutrons (N)

therefore ~

Number of Neutrons = 19

Answer:

the branch of science that deals with the identification of the substances of which matter is composed; the investigation of their properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances.

Explanation:

Hope this helps!

Answer:

100 m/ s²

Explanation:

Newton's Second Law of Motion:

[tex] \boxed{ \mathsf{force = mass \times acceleration}}[/tex]

___________________

In the question:

Note that the quantities here must be in their SI units.

SI unit of Force is Newton(N).

SI unit of mass is kilogram(kg)

Force is already in it's SI unit, while mass isn't.

Converting mass from grams to kilograms:

1000 g = 1 kg

=> 1 g = 1/ 1000 kg

=> 50 g = 50/ 1000 kg

= 1/ 20 kg

___________________

Calculating acceleration:

[tex] \mathsf{5 = \frac{1}{20} \times acceleration }[/tex]

multiplying both sides by 20:

[tex] \implies \mathsf{5 \times 20= (\frac{1}{20} \times 20)\times acceleration }[/tex]

20 on the RHS gets canceled, for it's present on the numerator as well as the denominator.

[tex] \implies \mathsf{100= acceleration }[/tex]

So, here, we got acceleration = 100 m/s².

Since, the other quantities used in the formula are in their SI units, acceleration must be in it's SI unit as well.

The SI unit of acceleration is m/s²

___________________

Answer:

[tex] \boxed{ \mathsf{100 \:m/s^2= acceleration }}[/tex]

The answer is the last option, Zn + S ➡️ ZnS.

Answer:

I think it is A

Explanation:

if I am wrong I am so so so sorry

but i'm pretty sure I am right.

please let me know if I am right :)

The hybridization state of the central sulfur atom is sp3d.

The valence shell electron pair repulsion theory describes the shape of molecules in terms of the number of electron pairs that surround the valence shell of the central atom in the molecule.

There are certain molecular shapes that are associated with certain hybridization states of the central atom. Since the central sulfur atom is trigonal bipyramidal, the hybridization state is sp3d.

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Answer:

I think it's is because during osmosis because when the cell duplicates in osmosis it divides into two smaller daughter cells; in diffusion there is a higher concentration near where it is but its getting smaller particles from where the source is

The designation "4" before Na2SO3 simply means that there are four molecules of sodium sulfite.

A molecule is formed when two or more atoms of the same or different elements come together. The formula of the molecule must reflect the number of atoms from which it is formed. The designation "4" before Na2SO3 simply means that there are four molecules of sodium sulfite.

The "The World on Turtle's Back" is a legend creation story. According to this story, the world was created on a giant turtle back. The folktale is common among the  Iroquois Native Americans.

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Answer:

TiCl₄

Explanation:

From the law of conservation of mass, the mass of the reactants must equal the mass of the products. In other words:

[tex]\displaystyle \text{m Cl$_2$} + \text{ m Ti} = \text{ m Ti$_x$Cl$_y$}[/tex]

Find the mass of chlorine gas reacted:

[tex]\displaystyle \begin{aligned} \text{ m Cl$_2$} + (0.532 \text{ g}) & = (2.108 \text{ g)} \\ \\ \text{m Cl$_2$} & = 1.576 \text{ g} \end{aligned}[/tex]

Find the number of moles of each reactant using their respective molecular weights:

[tex]\displaystyle 1.576 \text{ g Cl$_2$} \cdot \frac{1 \text{ mol Cl$_2$}}{70.90\text{ g Cl$_2$}} \cdot \frac{2\text{ mol Cl}}{1\text{ mol Cl$_2$}} = 0.04446\text{ mol Cl}[/tex]

And:

[tex]\displaystyle 0.532\text{ Ti} \cdot \frac{1\text{ mol Ti}}{47.87\text{ g Ti}} = 0.0111\text{ mol Ti}[/tex]

To find the empirical formula, all values by the smallest value:

[tex]\displaystyle \begin{aligned} \frac{0.0111\text{ mol Ti}}{0.0111} & = \frac{0.04446\text{ mol Cl}}{0.0111} \\ \\ 1\text{ mol Ti} & \approx 4\text{ mol Cl}\end{aligned}[/tex]

Hence, there are four moles of chlorine for every one mole of titanium.

In conclusion, our empirical formula is TiCl₄.

The heat of combustion of the sample is calculated to be  -1300 kJmol-1.

We know that energy is neither created nor destroyed but is converted from one form to another. The heat lost by the ethanol when it is burnt is equal to the heat gained by the calorimeter.

Heat gained by calorimeter =  2.×10^3 g ×  2. 45 Jg-1°C-1 × 1. 33°C

= 6.5 kJ

Number of moles of ethanol =  0. 2301 g/46 g/mol = 0.005 moles

Heat of combustion of the sample = -( 6.5/0.005 moles) = -1300 kJmol-1

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