What is the pH of a 6.50 x 10-3 M KOH solution?

Answer:

A.  not wearing goggles when breaking a rock with a hammer

Explanation:

You could get extremely hurt if you are not wearing goggles while doing lab work.

The action that reflects irresponsible lab safety behavior is not wearing goggles when breaking a rock with a hammer. Thus, the correct option for this question is A.

Lab safety behaviors may be defined as those actions and habits that are persistently taken by individuals in order to maintain discipline and safety on their own. Some of the lab safety behaviors are as follows:

Some of the lab safety behaviors also include not shaking hands with your lab partner after a successful experiment, not sharing findings and recordings with the general public, etc. This is because these are some private sources of information.

Therefore, the action that reflects irresponsible lab safety behavior is not wearing goggles when breaking a rock with a hammer. Thus, the correct option for this question is A.

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Answer:

Hey!

Your answer is element A

Explanation:

Using the graph, the element A's emission of radioactive particles ends approximately after 6 years...

A HALF-LIFE IS "HALF" OF THAT TIME PERIOD!

So if the radiation goes for 6 years the half-life is 6 divided by two which gives you 3 years!

The rest however have a longer half-life...

Because they all end at 14 yrs so their half-life in 7 years!

HOPE THIS HELPS!!

Answer: The answer would be D

Explanation:

The magnitude of the energy change of metal X during the experiment is 6500 J, and the mass of ice melted by metal X is 19.7 g and the claim of the student is correct.

The magnitude of energy change of metal is equal to the mass of metal x specific heat capacity of metal x temp. difference

= 100 g x 0.13 J / ( g- oC) x (500 - 0) oC

= 6500 J

According to the question, the enthalpy of the fusion of ice is 330 J / g

Thus 330 J heat is used to melt 1 g of ice

So 6500 J heat is used to melt = 1 x (6500 / 330) = 19.7 g ice

Although hydrogen bonds can form in both a solid and a liquid state, they are more stronger in the solid state. In order to partially dissolve its hydrogen bonds and turn solid ice into liquid water, whatever heat is applied to it is therefore used.

Therefore, the student's assertion is true.

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Answer:

The temperature at which a substance changes from the liq- uid state to the solid state is called the freezing point. The freez- ing point of the liquid state of a substance is the same temperature as the melting point of the solid state. For example, solid water melts at 0°C and liquid water freezes at 0°C.

Explanation:

Answer:  The volume of solution is 2248 ml

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in ml

moles of [tex]Mg(OH)_2[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{91.80g}{58.32g/mol}=1.574mol[/tex]

Now put all the given values in the formula of molality, we get

[tex]0.7=\frac{1.574\times 1000}{V_s}[/tex]

[tex]V_s=\frac{1.574\times 1000}{0.7}=2248ml[/tex]

Therefore, the volume of solution is 2248 ml

Answer:

fermentation

Explanation:

Answer:

A.

Explanation:

Sulfur has 6 valence electrons, therefore has 6 dots.

- Hope that helps! Please let me know if you need further explanation.

The correct option is A.

A Lewis electron dot diagram (or electron dot diagram, or a Lewis diagram, or a Lewis structure) is a representation of the valence electrons of an atom that uses dots around the symbol of the element. The number of dots equals the number of valence electrons in the atom.

These diagrams are helpful because they allow us to show how atoms are connected, and when coupled with Valence Shell Electron Repulsion Theory (VSEPR), we can use Lewis structures to predict the shape of the molecule.

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Answer:

The theoretical yield of

Li

3

N

is

20.9 g

.

Explanation:

Balanced Equation

6Li(s)

+

N

2

(

g

)

→

2Li

3

N(s)

In order to determine the theoretical yield, we must first find the limiting reactant (reagent), which will determine the greatest possible amount of product that can be produced.

Molar Masses

Li

:

6.941 g/mol

N

2

:

(

2

×

14.007

g/mol

)

=

28.014 g/mol

Li

3

N

:

(

3

×

6.941

g/mol Li

)

+

(

1

×

14.007

g/mol N

)

=

34.83 g/mol Li

3

N

Limiting Reactant

Divide the mass of each reactant by its molar mass, then multiply times the mole ratio from the balanced equation with the product on top and the reactant on bottom, then multiply times the molar mass of

Li

3

N

.

Lithium

12.5

g Li

×

1

mol Li

6.941

g Li

×

2

mol Li

3

N

6

mol Li

×

34.83

g Li

3

N

1

mol Li

3

N

=

20.9 g Li

3

N

Nitrogen Gas

34.1

g N

2

×

1

mol N

2

28.014

g N

2

×

2

mol Li

3

N

1

mol N

2

×

34.83

g Li

3

N

1

mol Li

3

N

=

84.8 g Li

3

N

Lithium produces less lithium nitride than nitrogen gas. Therefore, the limiting reactant is lithium, and the theoretical yield of lithium nitride is

20.9 g

.

Explanation:

Answer:

5.6L

Explanation:

At STP, the pressure and temperature of an ideal gas is

P = 1 atm

T = 273.15k

Volume =?

Mass = 9.5g

From ideal gas equation,

PV = nRT

P = pressure

V = volume

n = number of moles

R = ideal gas constant =0.082J/mol.K

T = temperature of the ideal gas

Number of moles = mass / molar mass

Molar mass of F2 = 37.99g/mol

Number of moles = mass / molar mass

Number of moles = 9.5 / 37.99

Number of moles = 0.25moles

PV = nRT

V = nRT/ P

V = (0.25 × 0.082 × 273.15) / 1

V = 5.599L = 5.6L

The volume of the gas is 5.6L

Answer: I italicize for checking

Explanation:

Rocks are preserved, as in you can't destroy them completely, but no, they don't stay the same they change.

Answer:

D

Explanation:

The safety equipment that is needed when your doing a science experiment you need a safety goggles and gloves.

Answer:

grond water

Explanation:

Answer:

They will both cool down overtime

Explanation:

Once you put something that is hot on something that is cold. They will both be hot, but overtime they will cool down. It can't stay hot forever.

Answer:

Hey!

Your answer is that one block of metal (the cold one) would heat up a bit whilst the other block (the hot one) would cool down...This is because of the metal's CONDUCTIVITY!

Explanation:

Eventually you would measure the temperature of both blocks and they will reach the same temperature. After this they will naturally cool down...

HOPE THIS HELPS!!

Answer:

Both are equal

Explanation:

Mass of starting material i.e Aluminium is [tex]4.480 * 10^{-23}[/tex] grams

The weight of oxygen is [tex]2.65 * 10^{-23}[/tex]

There are 4 atoms of aluminium and 3 atoms of oxygen

Thus, the total mass of starting material is

[tex]4 *[/tex] mass of one atom of aluminium [tex]+ 6 *[/tex] mass of one atom of oxygen

[tex]4 * 4.480 * 10^{-23} + 6* 2.65 * 10^{-23}[/tex]

[tex]35.1 * 10^{-23}[/tex] grams

Mass of new substance is also equal to

[tex]4 *[/tex] mass of one atom of aluminium [tex]+ 6 *[/tex] mass of one atom of oxygen

[tex]4 * 4.480 * 10^{-23} + 6* 2.65 * 10^{-23}[/tex]

[tex]35.1 * 10^{-23}[/tex] grams

Answer:

Calcium Nitride

Explanation:

Answer:

higher temperature → less kinetic energy → less space between particles higher volume

Explanation:

Answer:

HNO3

Explanation:

The ability of an acid to act as a Brownstead-Lowry acid depends on it's proton donation ability.

A Brownstead-Lowry acid is a specie that donates hydrogen ions in solution.

Considering all the chemical species listed among the options, HNO3 has the greatest hydrogen donation ability. It then follows that HNO3 is the strongest Brownstead-Lowry acid among the species listed.

Answer:

It is called catalyst.

Answer:

A catalyst

Explanation:

is a substance that can alter the rate of a chemical reaction. Catalysts can be successfully used to increase the rate of a chemical reaction.

Answer:

A. Energy  must be conserved in a nuclear reaction

Explanation:

Answer:

Explanation:

In a nuclear reaction, which of the following must be conserved?

A. Energy

Answer:

b.fission, because the reaction absorbed energy

Explanation:

The reaction is shown in the diagram is fission. because the reaction absorbed energy. Therefore, option B is correct.

The process of nuclear fission involves the splitting of an atom's nucleus into two or more smaller nuclei. Even by the energetic standards of radioactive decay, the fission process releases a very high quantity of energy and frequently results in gamma photons.

By dissolving large, heavy atoms, like uranium, into smaller ones, like iodine, caesium, strontium, xenon, and barium, to name just a few, fission produces energy. However, fusion involves joining light atoms, such as the deuterium and tritium isotopes of hydrogen, to create the heavier helium.

Nuclear fission is used by all nuclear power plants, and uranium atoms are typically used in nuclear power plants. A neutron splits a uranium atom when it collides with it during nuclear fission, releasing a significant quantity of energy.

Thus, option B is correct.

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Answer:

5.9 kg  

Explanation:

We must work backwards from the second step to work out the mass of oxygen.

1. Second step

Mᵣ:                                     55.84

            Fe₂O₃ + 3CO  ⟶  2Fe  +  3CO₂

m/kg:                                    7.0

(a) Moles of Fe

[tex]\text{Moles of FeO} = \text{7000 g Fe} \times \dfrac{\text{1 mol Fe}}{\text{55.84 g Fe}} = \text{125 mol Fe}[/tex]

(b) Moles of CO

[tex]\text{Moles of CO} = \text{125 mol Fe} \times \dfrac{\text{3 mol CO}}{\text{2 mol Fe}} = \text{188 mol CO}[/tex]

However, this is the theoretical yield.

The actual yield is 72. %.

We need more CO and Fe₂O₃ to get the theoretical yield of Fe.

(c) Percent yield

[tex]\begin{array}{rcl}\text{Percent yield} &=& \dfrac{\text{ actual yield}}{\text{ theoretical yield}} \times 100 \, \%\\\\ 72. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.72 &= &\dfrac{\text{188 mol}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{188 mol}}{0.72}\\& = & \textbf{261 mol}\\\\\end{array}[/tex]

We must use 261 mol of CO to get 7.0 kg of Fe.

2. First step

Mᵣ:                32.00

            2C   +  O₂   ⟶  2CO

n/mol:                             261

(a) Moles of O₂

[tex]\text{Moles of O}_{2} = \text{261 mol CO} \times \dfrac{\text{1 mol O}_{2}}{\text{2 mol CO}} = \text{131 mol O}_{2}[/tex]

(b) Mass of O₂

[tex]\text{Mass of O}_{2}= \text{131 mol O }_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \text{4180 g O}_{2}[/tex]

However, this is the theoretical yield.

The actual yield is 71. %.

We need more C and O₂ to get the theoretical yield of CO.

(c) Percent yield

[tex]\begin{array}{rcl}71. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.71 &= &\dfrac{\text{4180 g}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{4180 g}}{0.71}\\\\& = & \text{5900 g}\\& = & \textbf{5.9 kg}\\\end{array}[/tex]

We need 5.9 kg of O₂ to produce 7.0 kg of Fe.

Answer:

I need the things after "which of the following would occur".

Explanation:

If you were to maintain a constant volume while decreasing pressure, the temperature would also have to decrease. This is Boyle's law.

Answer:

Conduction

Hot water is conducting heat   because it is moving

Boiling water is an example of conduction heat transfer (option B).

Heat is one of the various forms in which energy can exist. Heat transfers with or without medium from one place to another.

There are three ways in which heat is transferred in the environment;

Conduction is the conveying of heat or electricity through a solid material such as the material used to boil water in this case. Therefore, option B is correct.

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Answer:

6.0 x 105

Explanation:

Answer:6.0 x l05

Explanation:

Answer:

A gene is a stretch of DNA or RNA that determines a certain trait. Genes mutate and can take two or more alternative forms; an allele is one of these forms of a gene. Chromosomes occur in pairs so organisms have two alleles for each gene one allele in each chromosome in the pair.

Answer:

b

Explanation:

hope it helps

Answer:

i agree with the above to collect rock samples

Explanation:

took test got 100 best of luck

The  purpose of the Apollo space missions was to to collect rock samples from the moon.

The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of Australia).The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term and larger than all known dwarf planets of the Solar System.

It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's at 0.1654 g, with Jupiter's moon Io being the only satellite in the Solar System known to have a higher surface gravity and density.

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Answer: Element

Explanation:

Answer: a proton is substance in which one or more atoms have the same number of protons