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2 years ago

Pls explain help would be appreciated

Chemistry

1 answer:

Sindrei [870]2 years ago

5 0

Answer:

Explanation:

many solids are crystalline hence a is eliminated

graphite contains free electrons while diamond uses all electrons in bonding and many substances have that property hence c is eliminated

only substances made up of carbon produce carbondioxide as the product when burnt

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A substance joined by this type of bond has a low melting point

cestrela7 [59]

Covalent compounds have bonds where electrons are shared between atoms. Due to the sharing of electrons, they exhibit characteristic physical properties that include lower melting points and electrical conductivity compared to ionic compounds.

5 0

3 years ago

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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>

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Chemistry

Unit 0

Reading a Periodic Table
Using Dimensional Analysis

Aqueous Solutions

Molarity = moles of solute / liters of solution

<h3>Explanation:</h3>

Step 1: Define

36.7 g CaF₂

300 mL H₂O

Step 2: Identify Conversions

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

Step 3: Convert

Solute

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

Solution

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

Step 4: Find Molarity

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

Step 5: Check

Follow sig fig rules and round. We are given 1 sig fig as our lowest.

1.56677 M ≈ 2 M

8 0

3 years ago

An atom of 14 6 c carbon decays by gamma decay which atom is left after the decay

ladessa [460]

Answer is: carbon.

During gamma emission the nucleus emits radiation without changing its composition, if for example have nucleus with six protons and six neutrons (carbon atom) and after gamma decay there is nucleus with six protons and six neutrons.
Gamma rays are the electromagnetic waves with the shortest wavelengths (1 pm), highest frequencies (300 EHz) and highest energy (1,24 MeV).

7 0

4 years ago

Read 2 more answers

5. Write a net ionic equation that occurs in a Na2HPO4/NaH2PO4 buffer solution when: A) a small amount of HCl is added (2 points

labwork [276]

Answer: (A) $H_{3}O^{+}(aq) + HPO^{2-}_{4}(aq) \rightarrow H_{2}PO^{2-}_{4}(aq) + H_{2}O(l)$

(B) $H_{2}PO^{-}_{4}(aq) + OH^{-}(aq) \rightarrow HPO^{2-}_{4}(aq) + H_{2}O(l)$

Explanation:

(A) As we know that HCl is a strong acid and when it is added to an aqueous solution then it leads to increase in the concentration of hydrogen ions. And, when an acid or base is added to a solution then any resistance by the solution in changing the pH of the solution is known as a buffer.

This means that addition of buffer into the given solution will not cause much change in the concentration of $H_{3}O^{+}$ in large amount.

As both the buffer components are salt then they will remain dissociated as follows.

$Na_{2}HPO_{4}(aq) \rightarrow 2Na^{+}(aq) + HPO^{2-}_{4}(aq)$

$NaH_{2}PO_{4}(aq) \rightarrow Na^{+}(aq) + H_{2}PO^{-}_{4}(aq)$

Hence, net ionic equation will be as follows.

$H_{3}O^{+}(aq) + HPO^{2-}_{4}(aq) \rightarrow H_{2}PO^{2-}_{4}(aq) + H_{2}O(l)$

(B) When we add small amount of sodium hydroxide into the solution then there will occur an increase in concentration of hydroxide ions into the solution. But then due to the presence of buffer there will occur not much change in concentration and the acid will get converted into salt.

$NaOH(aq) \rightarrow Na^{+}(aq) + OH^{-}(aq)$

The net ionic equation is as follows.

$H_{2}PO^{-}_{4}(aq) + OH^{-}(aq) \rightarrow HPO^{2-}_{4}(aq) + H_{2}O(l)$

7 0

3 years ago

To whoever helps me thank you so much have a wonderful day!

Schach [20]

Answer:

N and P

Explanation:

Anion:

When an atom gain the electrons anion is formed. The negative sign shows that atom gain electron because number of electron are greater than protons or we can say that negative charge becomes greater than positive charge.

Cation:

When atom lose electron cation is formed. The atom thus have positive charge because number of positive charge i.e protons are increased are greater than negative charge or electron.

In given problem N and phosphorus both can gain three electrons which means negative charge becomes greater that's why the extra electron gained by atoms are written as -3 and both form anion with charge -3.

while Al form cation with charge +3 Mg form cation with charge +2 and iodine and bromine both form anion with charge of -1.

8 0

3 years ago