Which of the following is a monatomic cation?

a. fr+ < -- i believe this is correct.

b. nh4+

c. br-

d. oh-

A. Fr+

Explanation:

A monatomic ion is an ion consisting of exactly one atom. If an ion contains more than one atom, even if these are of the same element, it is called a polyatomic ion. For example, calcium carbonate consists of the monatomic ion Ca²⁺ and the polyatomic ion CO₃²⁻.

150.5 °C

Explanation:

From the question given above, the following data were obtained:

Initial volume (V₁) = 4 L

Initial temperature (T₁) = 35 °C

Final volume (V₂) = 5.5 L

Final temperature (T₂) =?

Next, we shall convert 35 °C to Kelvin temperature. This can be obtained as follow:

T(K) = T(°C) + 273

Initial temperature (T₁) = 35 °C

Initial temperature (T₁) = 35 °C + 273

Initial temperature (T₁) = 308 K

Next, we shall determine the final (i.e the new) temperature of air. This can be obtained as follow:

Initial volume (V₁) = 4 L

Initial temperature (T₁) = 308 K

Final volume (V₂) = 5.5 L

Final temperature (T₂) =?

V₁ / T₁ = V₂ / T₂

4 / 308 = 5.5 / T₂

Cross multiply

4 × T₂ = 308 × 5.5

4 × T₂ = 1694

Divide both side by 4

T₂ = 1694 / 4

T₂ = 423.5 K

Finally, we shall convert 423.5 K to celsius temperature. This can be obtained as follow:

T(°C) = T(K) – 273

T₂ = 423.5 K

T₂ = 423.5 – 273

T₂ = 150.5 °C

Thus, the new temperature of the air is 150.5 °C