A dilute acid solution is prepared by adding the concentrated acid to water. If you do the reverse, i.e. add water to the acid it is possible that a small amount water could react with acid and boil and explode thus splashing the acid onto you or someone else near the activity.
Answer:
Astronomers use radar measurements, telemetry and exploration of solar system to get precise measurement of astronomical units.
Astronomers use parallax techniques. They measure the distance between the Earth and solar planets. Astronomers use parallax techniques to conduct parallax measurements which gave them accurate and precise values of the length of astronomical units
Explanation:
Astronomical unit is a unit length which is the average distance between the Earth and the sun which is about 150 millions kilometers.
Astronomers use radar measurements, telemetry and exploration of solar system to get precise measurement of astronomical units.
Astronomers use parallax techniques. They measure the distance between the Earth and solar planets. Astronomers use parallax techniques to conduct parallax measurements which gave them accurate and precise values of the length of astronomical units.
Answer:
Explanation: In my opinion law is stated as fact because it is passes through and approved by many peoples but theory is an idea someone has and is not approved and is set on a base of beliefs.
Answer:
in alpha decay, shown in Fig. 3-3, the nucleus emits a 4He nucleus, an alpha particle. Alpha decay occurs most often in massive nuclei that have too large a proton to neutron ratio. An alpha particle, with its two protons and two neutrons, is a very stable configuration of particles. Alpha radiation reduces the ratio of protons to neutrons in the parent nucleus, bringing it to a more stable configuration. Many nuclei more massive than lead decay by this method.
Explanation:
That will make a gold-202 nucleus.
<h3>Explanation</h3>
Refer to a periodic table. The atomic number of mercury Hg is 80.
Step One: Bombard the 
with a neutron 
. The neutron will add 1 to the mass number 202 of 
. However, the atomic number will stay the same.
- New mass number: 202 + 1 = 203.
- Atomic number is still 80.
.
Double check the equation:
- Sum of mass number on the left-hand side = 202 + 1 = 203 = Sum of mass number on the right-hand side.
- Sum of atomic number on the left-hand side = 80 = Sum of atomic number on the right-hand side.
Step Two: The 
nucleus loses a proton 
. Both the mass number 203 and the atomic number will decrease by 1.
- New mass number: 203 - 1 = 202.
- New atomic number: 80 - 1 = 79.
Refer to a periodic table. What's the element with atomic number 79? Gold Au.
.
Double check the equation:
- Sum of mass number on the left-hand side = 203 = 202 + 1 = Sum of mass number on the right-hand side.
- Sum of atomic number on the left-hand side = 80 = 79 + 1 = Sum of atomic number on the right-hand side.
A gold-202 nucleus is formed.
