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viktelen [127]
3 years ago
13

Donna has observed that her father can control the speed of their grandfather clock by adjusting the height of the weight on the

end of the pendulum. Donna thinks that the pendulum will move faster when the weight is lowered, and wants to test her idea. Donna gets a stopwatch and measures the time it takes for the pendulum to swing twenty times when the weight is moved to its lowest position. Donna begins to move the pendulum up by 1 cm and continues to measure the time for twenty swings of the pendulum. 1. What is the independent variable? 2. What is the dependent variable?
Chemistry
1 answer:
adelina 88 [10]3 years ago
4 0

Answer:

1. Independent variable : pendulum's height

2. Dependent variable : Pendulum speed

Explanation:

In an experiment scientist uses such things to search for any cause and its effect. experimenters design the model in such a way that change in one of the item causes a change in another.

These are called variables which are independent variable and dependent variable. Independent variables can be changed by the experimenter while dependent variables are not controllable by the experimenter.

In the context, the hypothesis is when the pendulum's height is reduced, the clock will speed up.

1. Independent variable : height of the pendulum

2. Dependent variable : Pendulum speed

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You are making a 1L solution that you want to be buffered with ammonia and ammonium. However ammonia is a gas that is difficult
zloy xaker [14]

Answer:

54 grams ammonium chloride and 40 grams sodium hydroxide

Explanation:

A buffer is a solution that contains either a weak acid and its salt or a weak base and its salt, the solution is resistant to changes in pH. This means that, a buffer is an aqueous solution of either a weak acid and its conjugate base or a weak base and its conjugate acid.

A Buffer is used to maintain a stable pH in a solution, buffers can neutralize small quantities of additional acid of base. For any buffer solution, there is always a working pH range and a set amount of acid or base that can be neutralized before the pH will change. The amount of acid or base that can be added to a buffer before changing its pH is called its buffer capacity.

A good buffer mixture is supposed to have about equal concentrations of its both components. It is a rule of thumb therefore, that a buffer solution has generally lost its usefulness when one component of the buffer pair is less than about 10% of the other component.

The implication of this is that the ammonium chloride and sodium hydroxide should be of approximately the same concentration. If the masses are dissolved as shown in the answer, then we will have 1molL-1 of each component of the buffer in accordance with the rule of thumb stated above.

4 0
3 years ago
For the reaction below, initially the partial pressure of all 3 gases is 1.0atm. . 2NH3(g)--> N2(g) + 3H2(g) K, 0.83 1. When
erma4kov [3.2K]

Answer:

The reaction would shift toward the reactants

When the reaction reach equilibrium the partial pressure of NH3 will be greater than 1atm

Explanation:

For the reaction:

2NH₃(g) ⇄ N₂(g) + 3H₂(g)

Where K is defined as:

K = \frac{P_{N_{2}}*P_{H_2}^3}{P_{NH_3}^2} = 0.83

As initial pressures of all 3 gases is 1.0atm, reaction quotient, Q, is:

Q = \frac{1atm*{1atm}^3}{1atm^2} = 1

As Q > K, <em>the reaction will produce more NH₃ until Q = K consuming N₂ and H₂.</em>

Thus, there are true:

<h3>The reaction would shift toward the reactants</h3><h3>When the reaction reach equilibrium the partial pressure of NH3 will be greater than 1atm</h3>

<em />

4 0
3 years ago
Is this a redox reaction? give evidence (many points plz answer)<br> 2Mg + CO2 → 2MgO + C
Aleonysh [2.5K]

Answer:

\boxed{yeah}

Explanation:

CO_2 \:  is \: reduced \: to→C \: by \:  2M_g \: (the \: reducing \: agent): while \\ 2M_g \: is \: oxydized \: to→2M_gO \: by \:  CO_2 \: (the \: oxydizing \: agent)

6 0
2 years ago
How many significant figures are in 1.00 L
likoan [24]

Answer:

3 significant numbers

6 0
3 years ago
Magnesium metal (0.100 mol) and a volume of aqueous hydrochloric acid that contains 0.500 mol of HCl are combined and react to c
jok3333 [9.3K]

Answer:

2.24 L of hydrogen gas, measured at STP, are produced.

Explanation:

Given, Moles of magnesium metal, Mg = 0.100 mol

Moles of hydrochloric acid, HCl = 0.500 mol

According to the reaction shown below:-

Mg_{(s)} + 2HCl_{(aq)}\rightarrow MgCl_2_{(aq)} + H_2_{(g)}

1 mole of Mg reacts with 2 moles of HCl

0.100 mol of Mg reacts with 2*0.100 mol of HCl

Moles of HCl must react = 0.200 mol

Available moles of HCl = 0.500 moles

Limiting reagent is the one which is present in small amount. Thus, Mg is limiting reagent.

The formation of the product is governed by the limiting reagent. So,

1 mole of Mg on reaction forms 1 mole of H_2

0.100 mole of Mg on reaction forms 0.100 mole of H_2

Mole of H_2 = 0.100 mol

At STP,  

Pressure = 1 atm  

Temperature = 273.15 K

Volume = ?

Using ideal gas equation as:

PV=nRT

where,  

P is the pressure

V is the volume

n is the number of moles

T is the temperature  

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

1 atm × V L = 0.100 × 0.0821 L.atm/K.mol × 273.15 K  

<u>⇒V = 2.24 L</u>

2.24 L of hydrogen gas, measured at STP, are produced.

4 0
3 years ago
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