Warning: foreach() argument must be of type array|object, bool given in /var/www/html/web/app/themes/studypress-core-theme/template-parts/header/mobile-offcanvas.php on line 20

According to the information provided, a sample that had a calculated δ18O of zero had a 18O/16O value that compared in which of the following ways to the 18 O/16O value of the standard sample? The sample's O/16O ratio was: F. 12 of the 18016 o ratio of the standard. G. the same as the $0/16 O ratio of the standard. H. 112 times larger than the 180% ratio of the standard. J. twice as large as the "O/' O ratio of the standard.

Short Answer

Expert verified
Question: If a sample has a calculated δ18O value of zero, the 18O / 16O ratio of the sample is: A. 1/2 of the 18O / 16O ratio of the standard B. the same as the 18O / 16O ratio of the standard C. 1 1/2 times larger than the 18O / 16O ratio of the standard D. twice as large as the 18O / 16O ratio of the standard Answer: B. the same as the 18O / 16O ratio of the standard

Step by step solution

01

1. Understanding the concept of δ18O

δ18O is a measure of the isotopic composition of oxygen in a sample with respect to a standard. It is calculated using the following formula: δ18O = (18O/16O)sample(18O/16O)standard1 Given that δ18O of the sample is zero, we can plug that value into the formula: 0 = (18O/16O)sample(18O/16O)standard1
02

2. Calculate the 18O/16O ratio of the sample

To find the 18O/16O ratio of the sample, we need to rearrange the equation: (18O/16O)sample = (18O/16O)standard×(1+δ18O) Since δ18O is zero, the equation becomes: (18O/16O)sample = (18O/16O)standard×(1+0) (18O/16O)sample = (18O/16O)standard
03

3. Compare the ratios and select the correct option

Now that we have found the relationship between the sample's 18O/16O ratio and the standard's 18O/16O ratio, we can compare it to the given options: F. 12 of the 18016 o ratio of the standard. This option suggests that the ratio in the sample is half of the standard, which is not true. G. the same as the $0/16 O ratio of the standard. This option suggests that the sample's ratio is the same as the standard, which is true, as we have established. H. 112 times larger than the 180% ratio of the standard. This option suggests that the ratio in the sample is 1.5 times the standard, which is not true. J. twice as large as the "O/' O ratio of the standard. This option suggests that the ratio in the sample is twice as large as the standard, which is not true. So, the correct answer is option G.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with Vaia!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Delta-18 Oxygen Notation
The term delta-18 oxygen notation may sound intricate, but it's simply a way scientists express the ratios of oxygen isotopes in substances like water or minerals. The notation uses a special form called \δ18O\ which is very significant in fields like climatology, hydrology, and paleoclimatology.

To grasp this concept, let's break it down: oxygen has several isotopes, of which 16O and 18O are the most common in natural waters. The \δ18O\ value tells us how the ratio of these two isotopes in a sample compares to a known standard. A \δ18O\ of zero means that the ratio of the isotopes in the sample is exactly the same as in the standard. When the \δ18O\ value is positive or negative, it indicates that the sample has a higher or lower 18O to 16O ratio, respectively, compared to the standard.

Decoding the \δ18O\ values offers insight into environmental conditions, as different processes can enrich or deplete the \18O isotope. For instance, rainwater often has lower \δ18O\ values than seawater because of evaporation and condensation processes that favor the lighter 16O isotope.
Isotopic Composition
Delving into isotopic composition deepens our understanding of various natural processes. The isotopic composition of an element is the proportion of its different isotopes present in a substance. In this context, we are interested in the isotopes of oxygen - 16O and 18O.

Isotopic measurements can reveal a lot. They are like historical records that can indicate temperature changes over time, the origin of water sources, or even paleoaltimetry, which is the study of historic elevations. When scientists analyze the ratio of 18O/16O, they often discover the effects of climatic conditions on the formation of a given sample.

Water molecules with heavy 18O are less likely to evaporate and more likely to condense. Thus, when we look at regions with a lot of rainfall, like the tropics, the rain has typically lower ratios of 18O because the heavy isotopes drop out first. As a result, the remaining cloud and rain further from these areas would become increasingly rich in 18O. This geological and climatic detective work is crucial in piecing together the vast puzzle of Earth's intricate systems.
Standard Sample Comparison
In standard sample comparison, scientists use a benchmark called a 'standard' to compare isotopic ratios from various samples against it. This standard is critical because it provides a fixed reference point that ensures that isotopic measurements are consistent over time and across different labs and studies.

The most commonly used standard for oxygen isotopes is known as Vienna Standard Mean Ocean Water (VSMOW). All \δ18O\ values are evaluated relative to this VSMOW standard. The VSMOW has a defined ratio of the 18O to 16O isotopes that is accepted worldwide. When we say that the \δ18O\ value of a sample is zero, it means that its isotopic composition exactly matches that of VSMOW.

The importance of using a standard cannot be underestimated in scientific research. It allows for replication of findings and guarantees that if different samples show a variance in their isotopic makeup, it is due to environmental, geographical, or other natural factors rather than discrepancies in measurement techniques.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Study anywhere. Anytime. Across all devices.

Sign-up for free