<span>Balanced nuclear reaction: 234/91 Pa → 4/2 He + 230/89 Ac.
1) number of protons and neutrons on both side of nuclear reaction must be the same. There are 91 protons (atomic number) and 143 neutrons (mass number - atomic number, 234 - 91 = 143 or (4-2) + (230 - 89) = 143)) on both side of reaction.
2) a</span>lpha
decay is radioactive decay<span> in which
an atomic nucleus emits
an alpha particle (helium
nucleus) and transforms into an atom with an atomic
number that is reduced by two and mass number that is reduced by four, so atomic mass of new element is 89 (91 - 2) and mass number is 230 (234 - 4 = 230).
3) look at atomic number, element with atomic number 89 is actinium.</span>
Answer:
C
Explanation:
It is also better so scientists know that the data is accurate and that the results will be reliable. If an investigation is replicable, somebody else can use it. In order for others to achieve the same results scientists also have to be able to collect the same data ...
The energy required to heat 40g of water from -7 c to 108 c is
1541000 joules
calculation
Q(heat)= M( mass) x c(specific heat capacity) xdelta t( change in temperature)
M= 40g= 40/1000= 0.04 Kg
C= 335,000 j/kg/c
delta T ( 108 --7= 115 c)
Q is therefore = 0.04 g x 335000 j/kg/c x 115 c = 1541,000 joules
Answer:
I think the answer is 368.544 centigrams
Explanation:
I hope I helped
The answers include:
- A loaf of risen but unbaked bread - chemical change.
- Photo by Elinor D - chemical change.
- Bread dough rising - chemical change.
<h3>What is a Chemical change?</h3>
This involves the formation of a new products from substances. In this scenario, a rising bread contains alcohol which evaporates.
Photographs also fall under this category and is therefore an irreversible chemical change.
Read more about Chemical change here
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