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4 years ago

Which of these substances are compounds? How do you know?

Chemistry

1 answer:

tankabanditka [31]4 years ago

7 0

Salt because it's a solid and helium and nitrogen are gases.
Water is a liquid because it's form can change.

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Does adding salt to water lower its freezing point science project

ser-zykov [4K]

Yes, it does. The freezing point of the salt solution is lower than the freezing point of pure water since there will be more particles, which are water molecules plus salt molecules, present in the salt solution. The salt molecules will slow down the amount of crystals formed resulting to a lower freezing point.

8 0

4 years ago

(100 POINTS) Write the chemical formula of the ionic compound magnesium chlorate. The magnesium (Mg) ion has a +2 charge. Chlora

antoniya [11.8K]

Answer:

Explanation:

since Mg has a charge of +2 and ClO3 has a charge of 1-, you need 2 ClO3 to cancel out the +2 since 2 ClO3 ions would have a 2- charge

6 0

3 years ago

Given: 36.7 grams of CaF2 is added to 300 mL water. Find molarity?

BigorU [14]

<h3>Answer:</h3>

2 M

<h3>General Formulas and Concepts:</h3>

<u>Math</u>

<u>Pre-Algebra</u>

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

<u>Chemistry</u>

Reading a Periodic Table
Using Dimensional Analysis

<u>Aqueous Solutions</u>

Molarity = moles of solute / liters of solution

<h3>Explanation:</h3>

<u>Step 1: Define</u>

36.7 g CaF₂

300 mL H₂O

<u>Step 2: Identify Conversions</u>

Molar Mass of Ca - 40.08 g/mol

Molar Mass of F - 19.00 g/mol

Molar Mass of CaF₂ - 40.08 + 2(19.00) = 78.08 g/mol

1000 mL = 1 L

<u>Step 3: Convert</u>

<em>Solute</em>

Set up: $\displaystyle 36.7 \ g \ CaF_2(\frac{1 \ mol \ CaF_2}{78.08 \ g \ CaF_2})$
Multiply: $\displaystyle 0.470031 \ mol \ CaF_2$

<em>Solution</em>

Set up: $\displaystyle 300 \ mL \ H_2O(\frac{1 \ L \ H_2O}{1000 \ mL \ H_2O})$
Multiply: $\displaystyle 0.3 \ L \ H_2O$

<u>Step 4: Find Molarity</u>

Substitute [M]: $\displaystyle x \ M = \frac{0.470031 \ mol \ CaF_2}{.3 \ L \ H_2O}$
Divide: $\displaystyle x = 1.56677 \ M$

<u>Step 5: Check</u>

<em>Follow sig fig rules and round.</em> <em>We are given 1 sig fig as our lowest.</em>

1.56677 M ≈ 2 M

8 0

3 years ago

How many atoms are found in 4.75 moles of Fe?

aliya0001 [1]

Answer:

The answer to your question is below

Explanation:

Number of atoms = ?

moles of Fe = 4.75

-Use proportions to solve this problem

1 mol of Fe --------------------- 6.023 x 10²³ atoms

4.75 moles --------------------- x

x = (4.75 x 6.023 x 10²³) / 1

x = 2.86 x 10²⁴ / 1

Number of atoms = 2.86 x 10²⁴

Number of moles = ?

moles of 1.058 moles of H₂O

I think this question is incorrect, maybe you wish to know the number of atoms or grams of H₂O.

Number of atoms = ?

moles of Fe = 0.759

1 mol of Fe ------------------ 6.023 x 10²³ atoms

0.759 moles --------------- x

x = (0.759 x 6.023 x 10²³) / 1

x = 4.57 x 10²³ / 1

Number of atoms of Fe = 4.57 x 10²³ atoms

Number of molecules = ?

moles of H₂O = 3.5 moles

1 mol of H₂O ------------------ 6.023 x 10²³ molecules

3.5 moles ------------------ x

x = (3.5 x 6.023 x 10²³) / 1

x = 2.11 x 10²⁴ molecules

Number of molecules = 2.11 x 10²⁴

7 0

4 years ago

#19.

navik [9.2K]

The answer above is correct:)

6 0

3 years ago