5 question review: answer the following questions about oxygen; 1. a. group number b. period number c…

1.

Explanation:

Step1: Identify group number of oxygen

Oxygen is in group 16.

Step2: Identify period number of oxygen

Oxygen is in period 2.

Step3: Identify family name of oxygen

Oxygen belongs to the chalcogen family.

Step4: Identify classification of oxygen

Oxygen is a non - metal.

Step5: Identify state of matter of oxygen

At standard temperature and pressure, oxygen is a gas.

Answer:

a. 16 b. 2 c. Chalcogen d. Non - metal e. Gas

2.

Explanation:

Step1: Recall density formula

The density formula is $\rho=\frac{m}{V}$, where $\rho$ is density, $m$ is mass and $V$ is volume. We need to solve for $V$, so $V = \frac{m}{\rho}$.

Step2: Substitute values

Given $m = 4.8g$ and $\rho=2.7g/mL$. Then $V=\frac{4.8g}{2.7g/mL}\approx1.78mL$.

Answer:

$1.78mL$

3.

Explanation:

Step1: Design experiment

Let's design an experiment to study the effect of light intensity on the rate of photosynthesis in plants. Place a plant in a beaker of water. Use different wattage light bulbs as a light source at a fixed distance from the plant.

Step2: Identify variables

The independent variable is the light intensity (changed by using different wattage light bulbs). The dependent variable is the rate of photosynthesis, which can be measured by the number of oxygen bubbles produced by the plant in a given time.

Answer:

Experiment: Place a plant in water and use different wattage light bulbs at a fixed distance. Independent variable: Light intensity (different wattage bulbs). Dependent variable: Rate of photosynthesis (number of oxygen bubbles in a given time)

4.

Explanation:

Step1: Write a problem

A student measures the mass of a sample of iron as 5.2g. The actual mass of the iron sample is 5.0g. Calculate the percent error.

Step2: Recall percent - error formula

The percent - error formula is $\text{Percent Error}=\frac{\vert\text{Measured Value}-\text{Actual Value}\vert}{\text{Actual Value}}\times100%$.

Step3: Substitute values

$\text{Measured Value}=5.2g$, $\text{Actual Value}=5.0g$. $\text{Percent Error}=\frac{\vert5.2 - 5.0\vert}{5.0}\times100%=\frac{0.2}{5.0}\times100% = 4%$.

Answer:

Problem: A student measures the mass of an iron sample as 5.2g, actual mass is 5.0g. Percent error calculation: $\text{Percent Error}=\frac{\vert5.2 - 5.0\vert}{5.0}\times100%=4%$

5.

Explanation:

Step1: List chemical properties

1. Reactivity with metals (e.g., iron reacts with oxygen to form iron oxide).
2. Combustibility support (many substances burn in the presence of oxygen).
3. Ability to form oxides with other elements.

Step2: List chemical changes

1. Rusting of iron (iron reacts with oxygen and water to form iron oxide).
2. Combustion of wood (wood reacts with oxygen to produce carbon dioxide, water and heat).
3. Decomposition of hydrogen peroxide in the presence of oxygen - producing enzymes (hydrogen peroxide decomposes into water and oxygen).

Answer:

Chemical properties: Reactivity with metals, Combustibility support, Ability to form oxides. Chemical changes: Rusting of iron, Combustion of wood, Decomposition of hydrogen peroxide.