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2 years ago

SCIENCE, PLEASE HELP.

Chemistry

2 answers:

sesenic [268]2 years ago

3 0

Answer: B

Explanation:

protons are positive,

electrons are negative,

and neutrons are neutral.

the amount of electrons to protons is always the same in a balanced atom.

electrons can be removed creating "ions" which is simply an unbalanced atom. removing protons would result in a different type of atom or element.

seraphim [82]2 years ago

3 0

Answer:

Neutron - neutral

Explanation:

This was the correct answer for the test I just took.

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Read the given expression. X = number of protons − number of core electrons Which of the following explains the identity of X an

shepuryov [24]

Answer: The correct statement is X is the effective nuclear charge, and it increases across a period.

Explanation:

We are given that:

X = number of protons − number of core electrons

Effective nuclear charge is defined as the actual nuclear charge (Z = number of protons) minus the screening effect caused by the electrons present between nucleus and valence electrons. These electrons are the core electrons.

The formula used for the calculation of effective nuclear charge given by Slater is:

$Z^*=Z-\sigma$

where,

$Z^*$ = effective nuclear charge

Z = atomic number or actual nuclear charge or number of protons

$\sigma$ = Screening constant

The effective nuclear charge increases as we go from left to right in a period because nuclear charge increases with no effective increase in screening constant.

Hence, the correct answer is X is the effective nuclear charge, and it increases across a period.

5 0

3 years ago

A and b are two gases that are mixed together: 2.50 mol a is mixed with 0.850 mol b. if the final pressure of the mixture is 1.7

USPshnik [31]

Partial pressure of gas A is 1.31 atm and that of gas B is 0.44 atm.

The partial pressure of a gas in a mixture can be calculated as

Pi = Xi x P

Where Pi is the partial pressure; Xi is mole fraction and P is the total pressure of the mixture.

Therefore we have Pa = Xa x P and Pb = Xb x P

Let us find Xa and Xb

Χa = mol a/ total moles = 2.50/(2.50+0.85) = 2.50/3.35 = 0.746

Xb = mol b/total moles = 0.85/(2.50+0.85) = 0.85/3.35 = 0.254

Total pressure P is given as 1.75 atm

Pa = Xa x P = 0.746 x 1.75 = 1.31atm

Partial pressure of gas A is 1.31 atm

Pb = Xb x P = 0.254 x 1.75 = 0.44atm

Partial pressure of gas B is 0.44 atm.

Learn more about Partial pressure here:

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6 0

1 year ago

What is the percent of hydrogen peroxide in the solution when 5.02g of H2O2 solution reacts to produce 0.153g of H2O2? 2H2O2 (l)

Murljashka [212]

Given:

Mass of H2O2 solution = 5.02 g

Mass of H2O2 = 0.153 g

To determine:

The % H2O2 in solution

Explanation:

Chemical reaction-

2H2O2(l) → 2H2O(l) + O2(g)

Mass % of a substance in a solution = (Mass of the substance/Mass of solution) * 100

In this case

% H2O2 = (Mass H2O2/Mass of solution)* 100 = (0.153/5.02)*100 = 3.05%

Ans: % H2O2 in the solution = 3.05%

5 0

2 years ago

An empty vial weighs 55.32 g. (a) If the vial weighs 185.56 g when filled with liquid mercury (d = 13.53 g/cm3). What i its volu

Tasya [4]

Answer:

a) Volume of vial= 9.626cm3

b) Mass of vial with water = 62.92 g

Explanation:

a) Mass of empty vial = 55.32 g

Mass of Vial + Hg = 185.56 g

Therefore,

$mass\ of\ Hg = 185.56-55.32 = 130.24 g$

Density of Hg = 13.53 g/cm3

$Volume\ of\ vial = Volume\ of\ Hg = \frac{Mass}{Density} \\\\= \frac{130.24g}{13.53g/cm3} = 9.626 cm3$

b) Volume of water = volume of vial = 9.626 cm3

Density of water = 0.997 g/cm3

$Mass\ of\ water = Density*volume = 0.997g/cm3*9.626cm3=9.60 g\\\\Total\ Mass\ of\ vial = Empty\ vial + mass\ of\ water\\= 53.32+9.60= 62.92g$

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2 years ago

Does graphite dissolve in cyclohexane

Brums [2.3K]

Answer: Graphite is nonpolar carbon which associates with the nonpolar hexanes. The cellulose in the exposed paper contains polar regions that are attracted to the polar water.

Explanation:

3 0

2 years ago