Please help me with this science

A student mixes chemicals A and B together and records the amount of time it takes for a color change to occur. The student repe

k0ka [10]

Answer:

It is mentioned that the student is mixing chemicals A and B and observes the time taken for the color to change. However, in the experiment, it is noticed that the student has repeated the procedure five times and each time he or she is modifying the concentration of chemical B. Thus, it is clear that the concentration of chemical B is the independent variable in the experiment. An independent variable is illustrated as the variable, which is controlled or modified in the experiment.

8 0

3 years ago

Coal can be used to generate hydrogen gas (a potential fuel) by thefollowing endothermic reaction.C(s) + H2O (g) <==> CO(g

SpyIntel [72]

Explanation:

Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.

This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.

For the given equation:

$C(s) + H_2O (g)\leftrightharpoons CO(g) + H_2(g)$

Given that reaction is an endothermic reaction.

For the given options:

a)Adding more C

If the concentration of C that is the reactant is increased, so according to the Le-Chatlier's principle, the equilibrium will shift in the direction where decrease of concentration of C takes place. Therefore, the equilibrium will shift in the right direction to wards the formation of hydrogen gas.

b) Adding more $H_2O$

If the concentration of water that is the reactant is increased, so according to the Le-Chatlier's principle, the equilibrium will shift in the direction where decrease of concentration of water takes place. Therefore, the equilibrium will shift in the right direction towards the formation of hydrogen gas.

c) Raising the temperature of the reaction mixture

If the temperature is increased,heat of the equilibrium mixture will also increase so according to the Le-Chatlier's principle , the equilibrium will shift in the direction where decrease in heat that is decrease in temperature occurs.

As, this is an endothermic reaction, forward reaction will decrease the temperature. Hence, the equilibrium will shift in the right direction that is towards the formation of hydrogen gas.

d) Increasing the volume of reaction mixture

If the volume of the container is increased, the pressure will decrease according to Boyle's Law. Now, according to the Le-Chatlier's principle, the equilibrium will shift in the direction where increase in pressure is taking place. As the number of moles of gas molecules is greater at the product side. So, the equilibrium will shift in the right direction that is towards the formation of hydrogen gas.

e) Adding a catalyst to reaction mixture

Role of catalyst is to attain the equilibrium quickly without disturbing the state of equilibrium. Hence, addition of catalyst will not change the equilibrium of the reaction.

f) Adding an inert gas to reaction mixture

Adding inert gas to the mixture at constant volume will not effect the equilibrium. Hence, addition of an inert gas will not change the equilibrium of the reaction.

6 0

3 years ago

Pls help asap!! plssss

kvv77 [185]

AgNO₃+NaCl⇒AgCl+NaNO₃

<h3>Further explanation</h3>

Double-Replacement reactions. Happens if there is an ion exchange between two ion compounds in the reactant to form two new ion compounds in the product

Reaction

AB + CD⇒AD + CB

So for the option :

1. synthesis/combination reaction

2. decomposition reaction

3. double replacement reaction

4. single replacement reaction

4 0

3 years ago

Crime scene investigators keep a wide variety of compounds on hand to help with identifying unknown substances they find in the

almond37 [142]

The powder could be acetaminophen, analgesic having chemical formula $C_{17}H_{21}NO_{4}$

<h3>What is an empirical formula?</h3>

A chemical formula showing the simplest ratio of elements in a compound rather than the total number of atoms in the molecule.

We are given:

Percentage of C = 67.31 %

Percentage of H = 6.978 %

Percentage of N = 4.617 %

Percentage of O = 21.10 %

Let the mass of the compound be 100 g. So, the percentages given are taken as mass.

Mass of C = 67.31 g

Mass of H = 6.978 g

Mass of N = 4.617 g

Mass of O = 21.10 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of carbon = $\frac{mass}{molar \;mass}$

Moles of carbon = $\frac{67.31g}{12g/mole}$

=5.60 moles

Moles of hydrogen = $\frac{mass}{molar \;mass}$

Moles of hydrogen = $\frac{6.978 g}{1 g/mole}$

=6.978 moles

Moles of nitrogen = $\frac{mass}{molar \;mass}$

Moles of nitrogen = $\frac{4.617 g}{14 g/mole}$

=0.329 moles

Moles of oxygen = $\frac{mass}{molar \;mass}$

Moles of oxygen = $\frac{21.10 g}{16 g/mole}$

=1.31 moles

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.329 moles.

We get the ratio of C : H : N : O = 17 : 21 : 1 : 4

The empirical formula for the given compound is $C_{17}H_{21}NO_{4}$ .

Learn more about the empirical formula here:

brainly.com/question/14044066

#SPJ1

3 0

2 years ago

Which of the following is converted into chemical energy during photosynthesis?

castortr0y [4]

Photosynthesis is commonly understood as converting light energy to chemical energy. So, C would be the correct answer.

6 0

3 years ago