题目内容
（请给出正确答案）
[单选题]
How many carbon atoms does deoxyribose have？
A.4
B.5
C.6
D.7
E.8
提问人：网友lixin080108
发布时间：2022-01-07
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A.5
B.2
C.3
D.4
题目内容
（请给出正确答案）
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更多“How many carbon atoms does deo…”相关的问题
第2题
Radiocarbon DatingNowadays scientists can answer many questions about the past through a t
Radiocarbon Dating
Nowadays scientists can answer many questions about the past through a technique called radiocarbon(放射性碳), or carbon-14, dating. One key to understanding how and why something happened is to discover when it happened.
Radiocarbon dating was developed in the late 1940s by physicist Willard F. Libby at the University of Chicago. An atom of ordinary carbon, called carbon-12, has six protons(质子) and six neutrons(中子) in its nucleus. Carbon-14, or C-14, is a radioactive, unstable form. of carbon that has two extra neutrons(原子核). It returns to a more stable form. of carbon through a process called decay(衰减). This process involves the loss of the extra neutrons and energy from the nucleus.
In Libby's radiocarbon dating technique, the weak radioactive emissions(放射) from this decay process are counted by instruments such as a radiation detector and counter. The decay rate is used to determine the proportion of C-14 atoms in the sample being dated.
Carbon-14 is produced in the Earth's atmosphere when nitrogen(氮)-14, or N-14, interacts with cosmic rays(宇宙射线). Scientists believe since the Earth was formed, the amount of nitrogen in the atmosphere has remained constant. Consequently, C-14 formation is thought to occur at a constant rate. Now ratio of C-14 to other carbon atoms in the atmosphere is known. Most scientists agree that this ratio is useful for dating items back to at least 50,000 years.
All life on Earth is made of organic molecules(分子) that contain carbon atoms coming from the atmosphere. So all living things have about the same ratio of C-14 atoms to other carbon atoms in their tissues(组织). Once an organism(有机体) dies it stops taking in carbon in any form, and the C-14 already present begins to decay. Over time the amount of C-14 in the material decreases, and the ratio of C-14 to other carbon atoms goes down. In terms of radiocarbon dating, the fewer C-14 atoms in a sample, the older that sample is.
Nowadays many scientists depend on radiocarbon for dating age-old objects.
A．Right
B．Wrong
C．Not mentioned
第3题
Radiocarbon DatingNowadays scientists can answer many questions about the past through a t
Radiocarbon Dating
Nowadays scientists can answer many questions about the past through a technique called radiocarbon(放射性碳), or carbon-14, dating. One key to understanding how and why something happened is to discover when it happened.
Radiocarbon dating was developed in the late 1940s by physicist Willard F. Libby at the University of Chicago. An atom of Ordinary carbon, called carbon-12, has six protons(质子) and six neutrons(中子) in its nucleus(原子核). Carbon-14, or C-14, is a radioactive, unstable form. of carbon that has two extra neutrons. It returns to a more stable form. of carbon through a process called decay(衰减). This process involves the loss of the extra neutrons and energy from the nucleus.
In Libby's radiocarbon dating technique, the weak radioactive emissions(放射) from this decay process are counted by instruments such as a radiation detector and counter. The decay rate is used to determine the proportion of C-14 atoms in the sample being dated.
Carbon-14 is produced in the Earth's atmosphere when nitrogen(氮)-14, or N-14, interacts with cosmic rays(宇宙射线). Scientists believe since the Earth was formed, the amount of nitrogen in the atmosphere has remained constant. Consequently, C-14 formation is thought to occur at a constant rate. Now ratio of C-14 to other carbon atoms in the atmosphere is known. Most scientists agree that this ratio is useful for dating items back to at least 50,000 years.
All life on Earth is made of organic molecules(分子) that contain carbon atoms coming from the atmosphere. So all living things have about the same ratio of C-14 atoms to other carbon atoms in their tissues(组织). Once an organism(有机体) dies it stops taking in carbon in any form, and the C-14 already present begins to decay. Over time the amount of C-14 in the material decreases, and the ratio of C-14 to other carbon atoms goes down. In terms of radiocarbon dating, the fewer C-14 atoms in a sample, the older that sample is.
Nowadays many scientists depend on radiocarbon for dating age-old objects.
A．Right
B．Wrong
C．Not mentioned
第4题
下面的短文后列出了7个句子，请根据短文的内容对每个句子做出判断：如果该句提供的是正确信息，请选
择A；如果该句提供的是错误信息，请选择B；如果该句的信息文中没有提及，请选择C。
点击查看答案
Radiocarbon Dating
Nowadays scientists can answer many questions about the past through a technique called radiocarbon (放射性碳), or carbon-14, dating. One key to understanding how and by something happened is to discover when it happened.
Radiocarbon dating was developed in the late 1940s by physicist Willard F. Libby at he University of Chicago. An atom of ordinary carbon, called carbon-12, has six protons(中子) and six neutrons (质子) in its nucleus. Carbon-14, or C-14, is a radioactive, unstable form. of carbon that has two extra neutrons (原子核). It returns to a more stable form. of carbon through a process called decay (衰减). This process involves the loss of he extra neutrons and energy from the nucleus.
In Libby's radiocarbon dating technique, the weak radioactive emissions (放射) from his decay process are counted by instruments such as a radiation detector and counter. He decay rate is used to determine the proportion of C-14 atoms in the sample being dated.
Carbon-14 is produced in the Earth's atmosphere when nitrogen (氮)-14, or N-14,
interacts with cosmic rays (宇宙射线). Scientists believe since the Earth was formed, the mount of nitrogen in the atmosphere has remained constant. Consequently, C-14 formation is thought to occur at a constant rate. Now the ratio of C-14 to other carbon toms in the atmosphere is known. Most scientists agree that this ratio is useful for dating items back to at least 50,000 years.
All life on Earth is made of organic molecules (分子) that contain carbon atoms coming from the atmosphere. So all living things have about the same ratio of C-14
atoms to other carbon atoms in their tissues (组织). Once an organism (有机体) dies it tops taking in carbon in any form, and the C-14 already present begins to decay. Over time the amount of C-14 in the material decreases, and the ratio of C-14 to other carbon toms goes down. In terms of radiocarbon dating, the fewer C-14 atoms in a sample, the older that sample is.
16 Nowadays many scientists depend on radiocarbon for dating age-old objects
A Right
B Wrong
C Not mentioned
第5题
An atom with the states 2G9/2 and 2H11/2 is placed in a weak magnetic field. How many transitions can be observed？ （)
A.12
B.20
C.35
D.30
第7题
Based on the relationship between electron configuration and the periodictable，indicate ho
w many (a)outershell electrons in an atom of germanium？ (b)elements whose atoms have six outershell electrons？ (c)shells of electrons in an atom of tungsten？ (d)transition elements in fifth period of elements？
点击查看答案
