What do you think are some of the most pressing environmental science issues

If the half life of iridium-182 is 15 years, how much of a 3 gram sample is left after 2 half-lives?

padilas [110]

Answer:

D. 0.75 grams

Explanation:

The data given on the iridium 182 are;

The half life of the iridium 182, $t_{(1/2)}$ = 15 years

The mass of the sample of iridium, N₀ = 3 grams

The amount left, N(t) after two half lives is given as follows;

$N(t) = N_0 \left (\dfrac{1}{2} \right )^{\dfrac{t}{t_{1/2}} }$

For two half lives, t = 2 × $t_{(1/2)}$

∴ t = 2 × 15 = 30

$\dfrac{t}{t_{(1/2)}} = \dfrac{30}{15} = 2$

$\therefore N(t) = 3 \times\left (\dfrac{1}{2} \right )^2 = 0.75$

∴ The amount left, N(t) = 0.75 grams

4 0

2 years ago

A cook places a pan of food on a hot stove and leaves it there. When the food is just about done cooking, which of the following

rjkz [21]

Answer:

C.

The pan will be the same temperature as the stove.

Explanation:

7 0

2 years ago

You decide to clean the bathroom. You notice that the shower is covered in a strange green slime . you try to get rid of this sl

Free_Kalibri [48]

The independent variable (IV) is the lemon juice mixture
The dependent variable (DV) is the appearance of the green slime on the shower
The control variable (CV) are time taken to spray, the amount of spray
The experimental group (EG) is the side of the shower sprayed with lemon juice mixture
The control group (CG) is the side of the shower sprayed with water.

INDEPENDENT VARIABLE

Independent variable is the variable of an experiment that is changed by the experimenter in order to bring about a change. It is the variable being tested in the experiment. In this case, the IV is the lemon juice mixture tested on the green slime on the shower.

DEPENDENT VARIABLE:

Dependent variable is the variable that is observed or measured in an experiment. It is also called responding variable. The DV in this case is the appearance of the green slime on the shower.

CONTROL VARIABLE:

Control variable is the variable that is kept constant throughout the experiment for all groups. The CV is the same for all the groups and they include: time taken to spray, the same amount of spray

CONTROL GROUP

Control group is the group that does not receive the independent variable or test in an experiment. In this case, the CG is the side of the shower sprayed with water.

EXPERIMENTAL GROUP:

Experimental group is the group of ab experiment that receives the experimental treatment or independent variable. In this case, the EG is the side of the shower sprayed with lemon juice mixture.

Therefore, the IV, DV, CV, EG and CG of this experiment are as follows:

The independent variable (IV) is the lemon juice mixture
The dependent variable (DV) is the appearance of the green slime on the shower
The control variable (CV) are time taken to spray, the amount of spray
The experimental group (EG) is the side of the shower sprayed with lemon juice mixture
The control group (CG) is the side of the shower sprayed with water.

Learn more: brainly.com/question/17498238?referrer=searchResults

7 0

2 years ago

Metals posses varying reduction potentials. Iron can reduce Cu+2 (aq) to copper metal. Silver can reduce Au+ (aq) to gold metal.

natta225 [31]

Answer: The true statement is iron can reduce $Au^+(aq)$ to gold metal

Explanation:

Single displacement reaction is defined as the reaction in which more reactive element displaces a less reactive element from its chemical reaction.

The reactivity of metal is determined by a series known as reactivity series. The metals lying above in the series are more reactive than the metals which lie below in the series.

$A+BC\rightarrow AC+B$