Which of the following have the greasiest ionization energy Bi, As, K or Ga?

An isotope of cesium-137 has a half-life of 30 years. If 5.0g of cesium-137 decays over 60 years. How many grams will remain.

LenKa [72]

Answer:

1.25 gram of cesium-137 will remain.

Explanation:

Given data:

Half life of cesium-137 = 30 year

Mass of cesium-137 = 5.0 g

Mass remain after 60 years = ?

Solution:

Number of half lives passed = Time elapsed / half life

Number of half lives passed = 60 year / 30 year

Number of half lives passed = 2

At time zero = 5.0 g

At first half life = 5.0 g/2 = 2.5 g

At 2nd half life = 2.5 g/ 2 = 1.25 g

Thus. 1.25 gram of cesium-137 will remain.

6 0

3 years ago

Question 2 (0 points)

bazaltina [42]

Answer:

The probability of spinning red with the spinner or rolling an odd number with the die is $\dfrac{1}{8}$

Explanation:

Given that,

Total color in spinner = 4

Let the area of four parts is equal in the spinner.

We need to calculate the probability of spinning red

Using formula of probability

$P(A) = \dfrac{Number\ of\ red\ color\ outcome}{Total\ number\ of\ colors\ in\ the\ spinner}$

Put the value into the formula

$P(A)=\dfrac{1}{4}$

We need to calculate the probability of odd number of the die

Using formula of probability

$P(B) = \dfrac{Number\ of\ odd\ digits\ outcome}{Total\ number\ of\ digits\ in\ the\ die}$

Put the value into the formula

$P(B)=\dfrac{3}{6}$

$P(B)=\dfrac{1}{2}$

We need to calculate the probability of spinning red with the spinner or rolling an odd number with the die

Using formula of probability of two events which is independent

$P(A\ and\ B)=P(A)\times P(B)$

Put the value into the formula

$P(A\ and\ B)=\dfrac{1}{4}\times\dfrac{1}{2}$

$P(A\ and\ B)=\dfrac{1}{8}$

Hence, The probability of spinning red with the spinner or rolling an odd number with the die is $\dfrac{1}{8}$

5 0

3 years ago

The concentration of a solution can be expressed in

puteri [66]

The concentration of a solution can be expressed in (4) <span>moles per liter~</span>

3 0

3 years ago

Read 2 more answers

Help I don't understand balancing equations

Semmy [17]

Answer:

Explanation: so I can help you with this I show you can you some examples that I’ve done in the past years

7 0

2 years ago

Consider the reaction of 19.0 g of zinc metal with excess silver nitrate to produce silver metal and zinc nitrate. The reaction

Alexeev081 [22]

Answer:

14.5 g silver

Explanation:

This is a problem using the stoichiometry of the reaction. First thing we need is the balanced equation:

Zn + 2 AgNO3 ----------------------- 2 Ag + Zn(NO3)2

We know that 14.6 g of Zn did not reacted, then we can calculate the amount of Zn reacted and do the calculation given the above reaction.

amount Zn reacted: 19.0 -14.6 g Zn = 4.4 g Zn

atomic weight of Zn: 65.37 g/mol

mol Zn reacted: 4.4 g Zn x ( 1 mol Zn/ 65.37 g Zn) = 0.067 mol Zn

We know from the balanced equation that moles of Ag are produced from 1 mol Zn therefore the mol of Ag produced are:

0.067 mol Zn x 2 mol Ag/ 1mol Zn = 0.135 mol Ag

and the mass of silver then will be given by multiplying by the atomic weight of silver:

0.135 mol Ag x 107.9 g/mol = 14.5 g Ag

4 0

3 years ago