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iVinArrow [24]
3 years ago
13

An atom of which element is represented by the model of a neutral atom? A Carbon (C) B Oxygen (O) C Sulfur (S) D Nitrogen (N) 6.

Which of the following describes a proton? I. Has mass II. Has no mass III. Has a positive charge IV. Found in the cloud V. Has a neutral charge A II, IV and V B I, III, IV C II and IV D I and III
Chemistry
1 answer:
jenyasd209 [6]3 years ago
6 0

Answer:

A. Carbon

B. I, III

Explanation:

Carbon has four valence eletrons meaning that it is more stable than the other choices. A proton has mass and has a positive charge.

You might be interested in
A water solution contains 1.704 [kg] of HNO3 per [kg] of water, and has a specific gravity of 1.382 at 20 [°C]. Please, express
Rudik [331]

Answer:

(a) The weight percent HNO3 is 63%.

(b) Density of HNO3 = 111.2 lb/ft3

(c) Molarity = 13792 mol HNO3/m3

Explanation:

(a) Weight percent HNO3

To calculate a weight percent of a component of a solution we can express:

wt = \frac{mass \, of \, solute}{mass \, of \, solution}=\frac{mass\,HNO_3}{mass \, HNO_3+mass \, H_2O}\\  \\wt=\frac{1.704}{1.704+1} =\frac{1.704}{2.704}= 0.63

(b) Density of HNO3, in lb/ft3

In this calculation, we use the specific gravity of the solution (1.382). We can start with the volume balance:

V_s=V_{HNO3}+V_w\\\\\frac{M_s}{\rho_s}=\frac{M_{HNO3}}{\rho_{HNO3}}+\frac{M_w}{\rho_w}\\\\\frac{M_{HNO3}}{\rho_{HNO3}} = \frac{M_s}{\rho_s}-\frac{M_w}{\rho_w}\\\\\rho_{HNO3}=\frac{M_{HNO3}}{\frac{M_s}{\rho_s}-\frac{M_w}{\rho_w}} \\\\ \rho_{HNO3}=\frac{1.704}{\frac{2.704}{1.382*\rho_w}+\frac{1}{\rho_w}} \\\\ \rho_{HNO3}=\frac{1.704}{2.956/ \rho_w}= 0.576*\rho_w[tex]V_s=V_{HNO3}+V_w\\\\\frac{M_s}{\rho_s}=\frac{M_{HNO3}}{\rho_{HNO3}}+\frac{M_w}{\rho_w}\\\\\frac{M_{HNO3}}{\rho_{HNO3}} = \frac{M_s}{\rho_s}-\frac{M_w}{\rho_w}\\\\\rho_{HNO3}=\frac{M_{HNO3}}{\frac{M_s}{\rho_s}-\frac{M_w}{\rho_w}} \\\\ \rho_{HNO3}=\frac{1.704}{\frac{2.704}{1.382*\rho_w}-\frac{1}{\rho_w}} \\\\ \rho_{HNO3}=\frac{1.704}{0.956/\rho_w}= 1.782*\rho_w

The density of HNO3 is 1.782 times the density of water (Sp Gr of 1.782). If the density of water is 62.4 lbs/ft3,

\rho_{HNO3}= 1.782*\rho_w=1.782*62.4 \, lbs/ft3=111.2\, lbs/ft3

(c) HNO3 molarity (mol HNO3/m3)

If we use the molar mass of HNO3: 63.012 g/mol, we can say that in 1,704 kg (or 1704 g) of HNO3 there are  1704/63.012=27.04 mol HNO3.

When there are 1.704 kg of NHO3 in solution, the total mass of the solution is (1.704+1)=2.704 kg.

If the specific gravity of the solution is 1.382 and the density of water at 20 degC is 998 kg/m3, the volume of the solution is

Vol=\frac{M_{sol}}{\rho_{sol}}=\frac{2.704\, kg}{1.382*998 \, kg/m3} = 0.00196m3

We can now calculate the molarity as

Molarity HNO_3=\frac{MolHNO3}{Vol}=\frac{27.04mol}{0.00196m3}  =13792 \frac{molHNO3}{m3}

8 0
3 years ago
A chemical formula is an expression used to represent
Evgen [1.6K]

Answer:

A chemical formula is an expression that shows the elements in a compound and the relative proportions of those elements.

Explanation:

If only one atom of a specific type is present, no subscript is used. For atoms that have two or more of a specific type of atom present, a subscript is written after the symbol for that atom

8 0
3 years ago
Rank the following substances in order from most soluble in water to least soluble in water: methane, CH4; 2-pentanol, C5H11OH;
Maru [420]

Answer:copper(II) sulfate, CuSO4> 2-pentanol, C5H11OH> methane, CH4>propane, C3H8.

Explanation:

Solubility depends on the ability of solute to interact effectively with a solvent. If water is the solvent, it interacts effectively with ionic substances. copper II sulphate is ionic and will be the most soluble in water, 2-pentanol, will interact effectively with water via hydrogen bonding. Between methane and propane, methane will interact better with water since it has a shorter alkyl chain than propane

7 0
3 years ago
Aluminum foil used for storing food weighs about 0.3 g per square inch. How many atoms of aluminum are contained in one square i
amm1812

Answer:

The number of atoms of aluminum contained in one square inch of the foil=6

Explanation:

Interpretation:

The number of atoms of aluminum contained in one square inch of the foil is to be calculated.

Concept introduction: relation to calculate a number of atoms contained in one square inch of the foil is given by:

 NA/c=mNA/AA1

Where,

M=mass of aluminum

NA= Avogadro's number

AA= Atomic mass of aluminum

Given :

Mass of aluminum foil=0.3 g

M= 0.39g

Relation to calculate a mass of atoms contained in one square inch of the foil is given by:

NA/c= mNA/AA1

M= Mass of aluminum

NA= Avogadro's number

AA= Atomic mass of aluminum

Since,

Avogadro's number

=6

4 0
3 years ago
PLEASE HELP ME I BEG YOU I REALLY NEED HELP!!!!
myrzilka [38]

1. they all can be emitted from the nucleus of an atom

2.they have different energies

3.the atom's mass number decreases by 4

4. have an atomic number greater than 83

5. False

6. both b and c

7.reduce the overall environmental impact of the waste by consolidating it

8. 2

9. a fission reaction

6 0
3 years ago
Read 2 more answers
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