Please help me with these questions please...

Bismuth-210 has a half life of 5.0 days if you had a sample of 60.00g of Bismuth-210 how much would be left after 15 days? (Show

Zielflug [23.3K]

Answer:

7.5 gm left

Explanation:

Bismuth-210 has a half life of 5 days

15 days is 15/5 = 3 half lives

since half the amount is left in 5 days or 1 half life

(1/2) x (1/2) x (1/2) the staring amount would be left in

3 half lives. so 1/8 is left

(1/8) x 60.0 = 7.5 gm left

5 0

3 years ago

Which statement about organic matter is false? A. Organic matter comes from organisms. B. Organic matter contains the element, c

siniylev [52]

B. Organic matter contains the element, carbon.

3 0

3 years ago

Read 2 more answers

Which of the following are acids by the Bronsted-Lowry Definition:

olga55 [171]

ANSWER IS (A)

EXPLANATION:

Bronsted-Lowry concept states that a substance is an acid if it can act as a H+ donor.

HCl in aqueous solution means that HCl is present in water, HCl + H2O --> H3O+ + Cl-. This reaction will take place, the H+ from HCl will be donated to H2O. So, HCl is a bronsted-lowry acid by definition.

However, Methanol (CH3OH) its written that it is liquid, i.e. pure methanol, CH3OH(l). It is both acidic as well as basic. when it is mixed with water then it behaves as an acid.

The last one ammonia in gas phase is also neutral because its not in water. if mixed in water it behaves as a base.

6 0

3 years ago

The table shows the number of reactants and products present during two separate chemical reactions.

finlep [7]

Answer:

Chemical reaction B, because the product is a compound

Explanation:

A synthesis or combination reaction is that reaction that involves combination of two or more reactants to form a single product. The two or more reactants are often elements that chemically combine to form a single compound.

In this question, two chemical reactions are involved in which chemical reaction A has 1 reactants and 3 products while chemical reaction B has 2 reactants and 1 product. Based on the explanation above, the reaction B correctly identifies the synthesis reaction because the single product is a compound.

4 0

3 years ago

Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid-fuel ro

melamori03 [73]

Answer: The mass of nickel (II) oxide and aluminium that must be used is 18.8 g and 4.54 g respectively.

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)