Astudent measures the range of sound frequencies that the human ear can hear by playing sounds for volunteers between 10 and 30,000 hertz and asking them to raise their hand if they were able to hear it. what type of variable is the independent variable in this experiment? a. categoric b. ordered c. continuous d. discrete

B. Ordered

Explanation:

Categorical Variable: A variable that has two or more categories is known as Categorical Variable. For example, Gender has two categorical variables i.e. Female or Male.

Ordered Variable: It is a categorical variable for which we can order them. For example, the Highest Education Level has variable Elementary School, High School, Some College, College Graduate. Here ordering is possible.

Continuous Variable: It is a variable that can not be count, it can be any value between the range. For example Height, Weight, etc.

Discrete variable: It is countable variable. It can be only certain values. For example Number of absent students in the class, etc.

Here, in the question, it will be ordered variable since here variable is the range of sound between 10 to 30,000 hertz.

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol

може ли да зареждате повече информация, моля