Question

This chemical reaction is balanced. True or False?

2 co2 + 1 h2o turns into 1 c2h2 + 3 o2
Answer
Looking at the periodic table, determine the number of valence electrons present in Potassium (K).



a
1 valence electron
b
4 valence electrons
c
2 valence electrons
d
3 valence electrons
Answer
Balance the following the chemical equation:

_ Na2O + _ CaBr2 → _ NaBr + _ CaO

a
1:2:1:1
b
1:1:2:1
c
1:1:1:2
d
2:1:1:1
Answer
Which event is an example of an exothermic reaction?

a
evaporation
b
decomposition
c
melting ice
d
combustion
Answer
How many valence electrons are in Oxygen?



a
3
b
1
c
4
d
6
Answer
Which statement correctly compares synthesis and decomposition reactions?



a
Synthesis and decomposition reactions are opposites of each other. Synthesis reactions are in the form A + B → AB, while decomposition reactions are in the form AB → A + B.
b
Synthesis and decomposition reactions are both neutralization reactions. Synthesis reactions are in the form AB → A + B, while decomposition reactions are in the form A + B → AB.
c
Synthesis and decomposition reactions are opposites of each other. Synthesis reactions are in the form AB → A + B, while decomposition reactions are in the form A + B → AB.
d
Synthesis and decomposition reactions are both neutralization reactions. Synthesis reactions are in the form A + B → AB, while decomposition reactions are in the form AB → A + B.
Answered by GPT-4o mini
To determine if the given chemical reaction is balanced, we need to count the number of atoms of each element on both sides of the equation.

**Reactants:**
- \(2 \text{CO}_2\):
- Carbon (C): 2
- Oxygen (O): 2 × 2 = 4
- \(1 \text{H}_2\text{O}\):
- Hydrogen (H): 2
- Oxygen (O): 1

Total for reactants:
- Carbon (C): 2
- Hydrogen (H): 2
- Oxygen (O): 4 + 1 = 5

**Products:**
- \(1 \text{C}_2\text{H}_2\):
- Carbon (C): 2
- Hydrogen (H): 2
- \(3 \text{O}_2\):
- Oxygen (O): 3 × 2 = 6

Total for products:
- Carbon (C): 2
- Hydrogen (H): 2
- Oxygen (O): 6

Now, we compare the totals:

- **Carbon**: 2 (reactants) = 2 (products)
- **Hydrogen**: 2 (reactants) = 2 (products)
- **Oxygen**: 5 (reactants) ≠ 6 (products)

Since the number of oxygen atoms is not equal on both sides of the equation, the reaction is **not balanced**.

So the answer is **False**.
Answered by GPT-4o mini
Potassium (K) is located in Group 1 of the periodic table. Elements in Group 1, also known as the alkali metals, have 1 valence electron.

Therefore, the correct answer is:

**a** 1 valence electron.
Answered by GPT-4o mini
To balance the chemical equation

\[
\_ \text{Na}_2\text{O} + \_ \text{CaBr}_2 \rightarrow \_ \text{NaBr} + \_ \text{CaO}
\]

let's analyze the number of atoms for each element on both sides.

**Reactants:**
- Sodium (Na): 2 from \( \text{Na}_2\text{O} \)
- Oxygen (O): 1 from \( \text{Na}_2\text{O} \)
- Calcium (Ca): 1 from \( \text{CaBr}_2 \)
- Bromine (Br): 2 from \( \text{CaBr}_2 \)

**Products:**
- Sodium (Na): 1 from \( \text{NaBr} \)
- Bromine (Br): 1 from \( \text{NaBr} \)
- Calcium (Ca): 1 from \( \text{CaO} \)
- Oxygen (O): 1 from \( \text{CaO} \)

To balance the equation, we can start by balancing the sodium and bromine:

1. We have 2 sodium atoms in the reactants, so we need 2 \( \text{NaBr} \) in the products:
\[
\text{Na}_2\text{O} + \text{CaBr}_2 \rightarrow 2 \text{NaBr} + \text{CaO}
\]

2. The equation after this adjustment will have:

- **Na**: 2 (reactants) = 2 (products)
- **Br**: 2 (reactants) = 2 (products)
- **Ca**: 1 (reactants) = 1 (products)
- **O**: 1 (reactants) = 1 (products)

Now the balanced equation is:

\[
1 \text{Na}_2\text{O} + 1 \text{CaBr}_2 \rightarrow 2 \text{NaBr} + 1 \text{CaO}
\]

Thus, the coefficients of the balanced equation are:

1 : 1 : 2 : 1

So the correct answer is:

**b** 1:1:2:1.
Answered by GPT-4o mini
An exothermic reaction is one that releases energy in the form of heat during the process.

Among the options provided:

a. **Evaporation** - This is an endothermic process because it requires energy (heat) to turn liquid into gas.

b. **Decomposition** - This can be endothermic, as some decomposition reactions require heat to break down compounds.

c. **Melting ice** - This is also an endothermic process, as it requires heat to change ice (solid) to water (liquid).

d. **Combustion** - This is an exothermic reaction because it releases energy, typically in the form of heat and light, when a substance (usually a fossil fuel) reacts with oxygen.

Therefore, the correct answer is:

**d** combustion.
Answered by GPT-4o mini
Oxygen is located in Group 16 (or Group 6A) of the periodic table. Elements in this group typically have 6 valence electrons.

Therefore, the correct answer is:

**d** 6.
Answered by GPT-4o mini
The correct statement that compares synthesis and decomposition reactions is:

**a** Synthesis and decomposition reactions are opposites of each other. Synthesis reactions are in the form A + B → AB, while decomposition reactions are in the form AB → A + B.

In synthesis reactions, two or more reactants combine to form a single product, represented as \( A + B \rightarrow AB \). In decomposition reactions, a single compound breaks down into two or more simpler products, represented as \( AB \rightarrow A + B \).

Thus, option **a** is accurate.