CHEMISTRY HIGH SCHOOL

Which of the following is a pure substance? Pure gold, pure milk, pure water, pure seawater, pure sand. And how do you know?

Answers

Answer 1
Answer: The one that is a pure substance is : Pure Gold

The other substance couldn't be categorized as 'pure substance' because they don't have definite and constant composition

hope this helps
Answer 2
Answer: Pure substances are made of almost the same materials and have the same properties such as: Water, Sugar, Salt, Nitrogen Gas, Iorn, Carbon and Oxygen Gas.

Related Questions

MIDDLE SCHOOL

What is the concentration of H+ ions at a pH = 2? mol/L

What is the concentration of OH-ions at a pH = 2?
mol/L

What is the ratio of H+ ions to OH-ions at a pH = 2?

Answers

At pH 2, the hydrogen ion concentration at pH 2 is 0.01 mol/L. The hydroxide ion concentration at pH 2 is mol/L. The ratio of hydrogen ion concentration to hydroxide ion concentration is .

pH can be described as the logarithmic value of the concentration of the hydrogen ion in a solution.

pH can be calculated as:

pH = log

=

The concentration of hydrogen ions at pH 2 will be:

=

The hydrogen ion concentration at pH 2 will be 0.01 mol/L.

The pH of the solution is 2.

Thus the pOH of the solution will be:

pH + pOH = 14

2 + pOH = 14

pOH = 12

pOH =

The hydroxide ion concentration at pH 2 will be:

The hydroxide ion concentration at pH 2 will be mol/L.

The ratio of hydrogen ion concentration to hydroxide ion concentration will be:

The ratio of hydrogen ion concentration to hydroxide ion concentration is .

At pH 2, the hydrogen ion concentration at pH 2 is 0.01 mol/L. The hydroxide ion concentration at pH 2 is mol/L. The ratio of hydrogen ion concentration to hydroxide ion concentration is .

For more information about the pH, refer to the link:

brainly.com/question/491373

Answer:

0.01

0.000000000001

10,000,000,000 : 1

Explanation:

COLLEGE

The volume of an automobile air bag was 66.8 l when inflated at 25 °c with 77.8 g of nitrogen gas. what was the pressure in the bag in kpa

Answers

For this question we can use the ideal gas equation,
PV = nRT
P - pressure 
V - volume - 66.8 / 1000 m³
n - number of moles - 77.8 g/ 28 g/mol = 2.77 mol 
R - universal gas constant - 8.314 Jmol⁻¹K⁻¹
T - 25 °C + 273 = 298 K
substituting these values in the equation 
P x 0.0668 m³ = 2.77 mol x 8.314 Jmol⁻¹K⁻¹ x 298 K 
P = 102.7 kPa
HIGH SCHOOL

When drawing a Fischer projection of a sugar, the horizontal line represents groups that are __________. a. projecting out of the plane of the drawing toward you
b. both hydroxyl groups
c. both hydrogen atoms
d. projecting behind the plane of the drawing

Answers

Answer:

The correct answer is a. projecting out of the plane of the drawing toward you.

Explanation:

Fisher's projection represents a way of showing tetrahedral carbon atoms with their substituent groups. . The vertical lines represent the groups that move away and the horizontal lines those that approach.

COLLEGE

Magnesium and nitrogen react in a combination reaction to produce magnesium nitride: 3 Mg + N2→ Mg3N2 In a particular experiment, a 5.65-g sample of N2 reacts completely. The mass of Mg consumed is ________ g.

Answers

Answer: The mass of magnesium consumed will be 14.731 g.

Explanation:

To calculate the number of moles, we use the equation:

 .....(1)

Given mass of nitrogen gas = 5.65 g

Molar mass of nitrogen gas = 28 g/mol

Putting values in above equation, we get:

For the given chemical equation:

By Stoichiometry of the reaction:

1 mole of nitrogen gas reacts with 3 moles of magnesium.

So, 0.202 moles of nitrogen gas will react with = of magnesium.

Now, calculating the mass of magnesium by using equation 1, we get:

Moles of magnesium = 0.606 moles

Molar mass of magnesium = 24.31 g/mol

Putting values in equation 1, we get:

Hence, the mass of magnesium consumed will be 14.731 g.

HIGH SCHOOL

What is the molecular formula for a compound that is 46.16% carbon, 5.16% hydrogen, and 48.68% fluorine? The molar mass of the compound is 156.12 g/mol

Answers

The molecular formula for a compound that is 46.16% carbon, 5.16% hydrogen, and 48.68% fluorine is C6H8F4.

HOW TO CALCULATE MOLECULAR FORMULA?

The molecular formula of a compound can be derived from the empirical formula, which can be calculated as follows:

  • % C = 46.16
  • % H = 5.16
  • % F = 48.68

Next, we calculate the no. of moles of each element:

  • moles of C = 46.16/12 = 3.847
  • moles of H = 5.16/1 = 5.16
  • moles of F = 48.68/19 = 2.562

Next, we calculate the mole ratio:

  • C = 3.847/2.562 = 1.50
  • H = 5.16/2.562 = 2.0
  • F = 2.562/2.562 = 1.0

Empirical formula = C3H4F2

Empirical formula mass = (12 × 3) + (1 × 4) + (2 × 19) = 78g/mol

Molecular mass = 156.12 g/mol

Ratio (n) = 156.12/78 = 2

Molecular formula = n(empirical formula) = 2(C3H4F2) = C6H8F4

Therefore, the molecular formula of a compound that is 46.16% carbon, 5.16% hydrogen, and 48.68% fluorine is C6H8F4.

Learn more about molecular formula at: brainly.com/question/1247523

Ans: Molecular formula = C₆H₈F₄

Given:

% C = 46.16

%H = 5.16

%F = 48.68

Calculate the # moles of each element:

moles of C = 46.16/12 = 3.847

moles of H = 5.16/1 = 5.16

moles of F = 48.68/19 = 2.562

Calculate the mole ratio:

C = 3.847/2.562 = 1.50

H = 5.16/2.562 = 2.0

F = 2.562/2,562 = 1.0

Empirical formula = C(1.5)H(2)F

Empirical formula mass = 12*1.5 + 1* 2+ 1*19 = 39 g/mol

Molecular mass = 156.12 g/mol

Ratio (n) = 156.12/39 = 4

Molecular formula = n(empirical formula) = 4(C1.5H2F) = C6H8F4

COLLEGE

Calculate the number of moles of magnesium, chlorine, and oxygen atoms in 2.60 moles of magnesium perchlorate, mg(clo4)2. express the number of moles of mg, cl, and o atoms numerically, separated by commas.

Answers

In this question, there are  2.60 moles of magnesium perchlorate which has a formula of Mg(ClO4)2. To find the separate number of each kind of atom, you need to know the total number of atoms for every magnesium perchlorate. 
The unabbreviated formula should be Mg ClO4 ClO4. From this name, you can know that there is 1 Mg, 2Cl ad 8 O. Then the number of mols should be:

Mg= 1*2.6 moles= 2.6 moles
Cl= 2*2.6 moles= 5.2 moles
O= 8*2.6 moles= 20.8 moles
COLLEGE

Molecular compounds of low molecular weight tend to be gases at room temperature. Which of the following is most likely not a gas at room temperature? Molecular compounds of low molecular weight tend to be gases at room temperature. Which of the following is most likely not a gas at room temperature? NaBr CO2 HCN N2 NH3

Answers

Sodium bromide (NaBr) is most likely not a gas at room temperature.

WHAT IS A GAS?

A gas is one of the three states in which matter can exist. A gas is characterized by its particles that moves randomly.

According to this question, a gas is a molecular compound of low molecular weight.

This means that the following compounds with their molecular weight are gases:

  1. carbon dioxide- 44 g/mol
  2. Ammonia = 17 g/mol
  3. Hydrogen cyanide = 27.03 g/mol

Therefore, sodium bromide (NaBr) with a molecular weight of 102.09g/mol is most likely not a gas.

Learn more about gases at: brainly.com/question/1369730

Answer: Option (a) is the correct answer.

Explanation:

Sodium bromide (NaBr) is an ionic salt as it is formed by transfer of an electron from sodium to bromine atom.

Whereas , HCN, and are all covalent compounds. And, all of them exists as a gas at room temperature.

Also according to rate of diffusion law, rate of diffusion is inversely proportional to square root of molecular weight of gas.

Mathematically,  Rate of diffusion =

Out of the given options NaBr has the highest molecular weight which is 102.894 g/mol.

Thus, we can conclude that NaBr is most likely not a gas at room temperature.

MIDDLE SCHOOL

A lab technician needs to create 570.0 milliliters of a 2.00 M solution of magnesium chloride (MgCl2). To make this solution, how many grams of magnesium chloride does the technician need?

Answers

Hey there!:

Molar mass MgCl2 = 95.211 g/mol

Volume of solution in liters:

570.0 mL / 1000 => 0.57 L

Number of moles:

n = M * V

n = 2.00 * 0.57 => 1.14 moles of MgCl2

Therefore:

1 mol MgCl2 --------------- 95.211 g

1.14 moles MgCl2 ---------- ??

mass of MgCl2 = 1.14 * 95.211

mass of MgCl2 = 108.54 g


Hope that helps!

109 for brainly just did it 5/5 correct (Three significant figures)

HIGH SCHOOL

Which substance can not be broken down by a chemical reaction? (1) ammonia (3) methane
(2) argon (4) water

Answers


The substance that cannot be broken down by a chemical reaction is argon. This is because the substance is an element, otherwise if this is a compound, then it can be still broken down by chemical means. Ammonia, methane and water are all compounds. 

The substance that cannot be broken down by chemical reaction is .

Further Explanation:

Substance is the pure form of matter while combination of atoms or molecules is termed as a mixture.

Types of substances:

1. Element

The simplest form of substance that cannot be further broken down by any chemical method is known as an element. Carbon, sulfur, and cobalt are some of the examples of elements.

2. Compound

When two or more different elements are held together by chemical bonds, compounds are formed. These can further be broken down into their respective constituents. Their properties are quite different from those of their constituent elements. NaCl, and are examples of compounds.

(1) Ammonia consists of one nitrogen and three hydrogen atoms so it is a compound. Therefore it can be broken down by chemical reactions.

(2) Argon is an element so it is the simplest form in which it can exist. Therefore it cannot be broken down by chemical reactions.

(3) Methane consists of one carbon and four hydrogen atoms so it a compound. Therefore it can be broken down by chemical reactions.

(4) Water consists of one oxygen and two hydrogen atoms so it is a compound. Therefore it can be broken down by chemical reactions.

Learn more:

  1. Which sample is a pure substance? brainly.com/question/2227438
  2. Which is a characteristic of a mixture? brainly.com/question/1917079

Answer details:

Grade: High School

Subject: Chemistry

Chapter: Elements, compounds, and mixtures

Keywords: substance, methane, argon, ammonia, water, element, compound, chemical reactions, broken down, simplest form, NaCl, CH4, carbon, sulfur, cobalt.

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