A flask contains `2.0xx10^(13)` molecules of `CO_(2)`. To this `1.5xx10^(14)` molecules of `CO_(2)` are added.
The number of molecules in the flask now is

Options

A. `3.5xx10^(13)`
B. `3.5xx10^(14)`
C. `1.7xx10^(14)`
D. None of these

Explanation

To find the total number of molecules of CO₂ in the flask after adding more molecules, we can follow these steps:

### Step 1: Identify the initial number of molecules
The initial number of CO₂ molecules in the flask is given as:
\[ 2.0 \times 10^{13} \text{ molecules} \]

### Step 2: Identify the number of molecules added
The number of CO₂ molecules added to the flask is:
\[ 1.5 \times 10^{14} \text{ molecules} \]

### Step 3: Convert both numbers to the same power of ten
To add the two quantities, we need to express them with the same exponent. The smaller exponent is \(10^{13}\). We can rewrite \(1.5 \times 10^{14}\) as:
\[ 1.5 \times 10^{14} = 15.0 \times 10^{13} \]

### Step 4: Add the two quantities
Now we can add the two quantities:
\[ 2.0 \times 10^{13} + 15.0 \times 10^{13} = (2.0 + 15.0) \times 10^{13} = 17.0 \times 10^{13} \]

### Step 5: Convert the result to standard scientific notation
The result \(17.0 \times 10^{13}\) can be expressed in standard scientific notation as:
\[ 1.7 \times 10^{14} \]

### Final Answer
Thus, the total number of CO₂ molecules in the flask now is:
\[ \boxed{1.7 \times 10^{14}} \]

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