1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
lozanna [386]
3 years ago
8

2. How old are the oldest fossils? Oldest rocks?During what period were these found? IT

Chemistry
1 answer:
Andre45 [30]3 years ago
8 0

Answer:

Fossils: 3.5 billion.  Rocks: 4.28 billion

they were found during Haden Eon

Explanation:

You might be interested in
Radioactive manganese-52 decays with a half-life of 5.6 days. A chemist obtains a fresh sample of manganese-52 and measures its
LUCKY_DIMON [66]

Answer: 11.2 days

Explanation:

Expression for rate law for first order kinetics is given by:

t=\frac{2.303}{k}\log\frac{a}{a-x}

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant

a - x = amount left after decay process  

a) for completion of half life:

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

t_{\frac{1}{2}}=\frac{0.693}{k}

k=\frac{0.693}{5.6days}=0.124days^{-1}

b) for completion of 75% of reaction

t=\frac{2.303}{0.124}\log\frac{100}{100-75}

t=\frac{2.303}{0.124}\log\frac{100}{25}

t=11.2days

The time for which she has to perform the experiment is 11.2 days

5 0
3 years ago
Hydrogen gas can be made by reacting methane (CH4) with high temperature steam: CH4(g) + H2O(g) ---> CO(g) + 3H2(g)
zavuch27 [327]
66.2 kg 1) 25 kg H X (1 mol / 2.016) X (16.043 / 1 mol)= 66.2kg I am sorry if this is not what you looking for my friend
6 0
3 years ago
Read 2 more answers
For the following reaction, provide the missing information
jenyasd209 [6]

Answer:

19. Option B. ⁰₋₁B

20. Option D. ²¹⁰₈₄Po

Explanation:

19. ²²⁸₈₈Ra —> ²²⁸₈₉Ac + ʸₓZ

Thus, we can determine ʸₓZ as follow:

228 = 228 + y

Collect like terms

228 – 228 = y

y = 0

88 = 89 + x

Collect like terms

88 – 89 = x

x = –1

Thus,

ʸ ₓZ => ⁰₋₁Z => ⁰₋₁B

²²⁸₈₈Ra —> ²²⁸₈₉Ac + ʸₓZ

²²⁸₈₈Ra —> ²²⁸₈₉Ac + ⁰₋₁B

20. ᵘᵥX —> ²⁰⁶₈₂Pb + ⁴₂He

Thus, we can determine ᵘᵥX as follow:

u = 206 + 4

u = 210

v = 82 + 2

v = 84

Thus,

ᵘᵥX => ²¹⁰₈₄X => ²¹⁰₈₄Po

ᵘᵥX —> ²⁰⁶₈₂Pb + ⁴₂He

²¹⁰₈₄Po —> ²⁰⁶₈₂Pb + ⁴₂He

8 0
3 years ago
What type(s) of atoms make up the element carbon?
ivolga24 [154]
A, as carbon is an atomic substance - element
8 0
3 years ago
Read 2 more answers
A van moves with a constant speed
Kitty [74]

Answer:

1.5 hours or 90 minutes

Explanation:

Velocity = d/t

V = 64 mi / hour or 96 mi / 9 min OR 16 mi / 15 min

D = 96 miles

Velocity * Time = Distance

Time = Distance / Velocity

T = 96 mi / 64 mi / hour

96 / 64 = 1.5 mi per hour

T = 1.5 hours or 90 minutes

4 0
3 years ago
Other questions:
  • Byetta ( generic name is exenatide) 5mcg BID within 60 minutes AC
    11·1 answer
  • When hcl(aq) and naoh(aq) are mixed in a beaker, the beaker feels warm to the touch. what is known about the enthalpy of this re
    6·1 answer
  • Fill missing reagents.
    10·1 answer
  • What is the concentration of a solution made by dissolving 0.99mol of acetic acid in enough water to make 0.58L of solution?
    5·1 answer
  • Which circult is a serles circult?​
    14·1 answer
  • It is used to lift water from a well​
    5·1 answer
  • How many moles of HCl are needed to react with 0.87 mol Al?
    8·1 answer
  • Two different isotopes of an element have different?
    8·1 answer
  • The sun is located in the center of our solar system. Where is the sun located in our disc-shaped
    11·1 answer
  • You have 100 grams of each fuel. How many moles of each fuel do you have?
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!