All categories

4 years ago

Help me with these questions :)

Chemistry

1 answer:

maxonik [38]4 years ago

3 0

Answer:

1 ) H2O 2) Hydrogen and oxygen 3) Compound

Explanation:

1) To write a chemical formula, you write the number of molecules of an element (2 hydrogen atoms + 1 Oxygen atom, or H2O). The letters represent the element's notation on the periodic table, while the number that follows it represents the number of atoms of that particular element within the compound. If there is no number that follows the letter, there is only one.

2) Letter "H" on the periodic table represents hydrogen, while "O" represents oxygen

3) You can tell that this is a compound because it is made of two or more elements found on the periodic table

You might be interested in

Find the empirical formula of each of the following compounds. Given mass or for each element in a sample of the compound 3,611

KengaRu [80]

Answer:

CaCl₂

Step-by-step explanation:

The empirical formula is the simplest whole-number ratio of atoms in a compound.

The ratio of atoms is the same as the ratio of moles.

So, our job is to calculate the molar ratio of Ca to Cl.

Data:

Mass of Ca = 3.611 g

Mass of Cl = 6.389 g

Calculations

Step 1. Calculate the moles of each element

Moles of Ca = 3.611 g Ca × (1 mol Ca/(40.08 g Ca)= 0.090 10 mol Ca

Moles of Cl = 6.389 g Cl

Step 2. Calculate the molar ratio of the elements

Divide each number by the smallest number of moles

Ca:Cl = 0.090 10:0.1802 = 1:2.000

Step 3. Round the molar ratios to the nearest integer

Ca:Cl = 1:2.000 ≈ 1:2

Step 4: Write the empirical formula

EF = CaCl₂

8 0

3 years ago

Percentage Yield

scoundrel [369]

Q.No. 1:

You have 20.0 g of CaCO₃. You decompose it by heat, and weigh the calcium oxide that remains. You have 10.3 grams. What is the % yield?

Answer:

%age Yield = 92.37 %

Solution:

The balance chemical equation for given decomposition reaction is;

CaCO₃ → CaO + CO₂

Step 1: Calculate Moles of CaCO₃:

Moles = Mass / M.Mass

Moles = 20.0 g / 100.08 g/mol

Moles = 0.199 moles of CaCO₃

Step 2: Calculate theoretical amount of CaO produced;

According to equation,

1 moles of CaCO₃ produced = 1 mole of CaO

So,

0.199 moles of CaCO₃ will produce = X moles of CaO

Solving for X,

X = 0.199 mol × 1 mol / 1 mol

X = 0.199 mol of CaO

Also,

Mass = Moles × M.Mass

Mass = 0.199 mol × 56.07 g/mol

Mass = 11.15 g of CaO

Step 3: Calculate %age Yield as;

%age Yield = Actual Yield / Theoretical Yield × 100

%age Yield = 10.3 g / 11.15 g × 100

%age Yield = 92.37 %

___________________________________________

Q.No. 2:

A student makes sodium chloride by buming 2.3 grams of sodium in chlorine gas. If the yield is 90%, how much sodium chloride is made?

Answer:

Actual Yield = 5.785 g of NaCl

Solution:

The balance chemical equation for given decomposition reaction is;

2 Na + Cl₂ → 2 NaCl

Step 1: Calculate Moles of Na:

Moles = Mass / M.Mass

Moles = 2.3 g / 23 g/mol

Moles = 0.10 moles of Na

Step 2: Calculate theoretical amount of NaCl produced;

According to equation,

2 moles of Na produced = 2 moles of NaCl

So,

0.10 moles of Na will produce = X moles of NaCl

Solving for X,

X = 0.10 mol × 2 mol / 2 mol

X = 0.10 mol of NaCl

Also,

Mass = Moles × M.Mass

Mass = 0.10 mol × 58.44 g/mol

Mass = 5.844 g of NaCl

Step 3: Calculate Actual Yield as;

%age Yield = Actual Yield / Theoretical Yield × 100

Or,

Actual Yield = %age Yield × Theoretical Yield ÷ 100

Actual Yield = 99 × 5.844 g ÷ 100

Actual Yield = 5.785 g of NaCl

___________________________________________

Q.No. 3:

For the chemical reaction Mg(s) + 2 HCl (aq) → H₂ (g) + MgCl₂ (aq) calculate the % yield if 100 grams of magnesium react with excess HCl to produce 310 grams of MgCl₂.

Answer:

%age Yield = 79.13 %

Solution:

The balance chemical equation for given decomposition reaction is;

Mg + 2 HCl → MgCl₂ + H₂

Step 1: Calculate Moles of Mg:

Moles = Mass / M.Mass

Moles = 100 g / 24.30 g/mol

Moles = 4.11 moles of Mg

Step 2: Calculate theoretical amount of MgCl₂ produced;

According to equation,

1 mole of Mg produced = 1 mole of MgCl₂

So,

4.11 moles of Mg will produce = X moles of MgCl₂

Solving for X,

X = 4.11 mol × 1 mol / 1 mol

X = 4.11 mol of MgCl₂

Also,

Mass = Moles × M.Mass

Mass = 4.11 mol × 95.21 g/mol

Mass = 391.73 g of MgCl₂

Step 3: Calculate %age Yield as;

%age Yield = Actual Yield / Theoretical Yield × 100

%age Yield = 310.0 g / 391.73 g × 100

%age Yield = 79.13 %

5 0

4 years ago

A chemistry student weighs out of lactic acid into a volumetric flask and dilutes to the mark with distilled water. He plans to

34kurt

Answer:

28.0mL of the 0.0500M NaOH solution

Explanation:

0.126g of lactic acid diluted to 250mL. Titrated with 0.0500M NaOH solution.

The reaction of lactic acid, H₃C-CH(OH)-COOH (Molar mass: 90.08g/mol) with NaOH is:

H₃C-CH(OH)-COOH + NaOH → H₃C-CH(OH)-COO⁻ + Na⁺ + H₂O

Where 1 mole of the acid reacts per mole of the base.

You must know the student will reach equivalence point when moles of lactic acid = moles NaOH.

the student will titrate the 0.126g of H₃C-CH(OH)-COOH. In moles (Using molar mass) are:

0.126g ₓ (1mol / 90.08g) = 1.40x10⁻³ moles of H₃C-CH(OH)-COOH

To reach equivalence point, the student must add 1.40x10⁻³ moles of NaOH. These moles comes from:

1.40x10⁻³ moles of NaOH ₓ (1L / 0.0500moles NaOH) = 0.0280L of the 0.0500M NaOH =

<h3>28.0mL of the 0.0500M NaOH solution</h3>

8 0

3 years ago

What subatomic particle is specifically responsible for combining the atoms together to form a new substance?

mestny [16]

Electron

Atoms, compounds, and molecules undergo chemical reactions to form new substances. In general, reactions proceed to produce products which are have more stability.

These chemical reactions are possible because of the ability of substances to form chemical bonds with other substances. These formation of bonds are primarily attributed to electronic interactions (i.e. the valence or outer electrons of the atoms). of substances.

Atoms are able to form new substances by gaining, losing, or sharing electrons with other atoms.

3 0

3 years ago

Which statement best describes how temperature, humidity, and pressure vary within an air mass?

IRISSAK [1]

Temperature, humidity,and pressure are basically the same

8 0

3 years ago

Read 2 more answers