What is the value of x, y and z in the following chemical equation?
xPbO(s) + C(s) → yPb(s) + zCO2(g)
x = 2, y = 2, z = 1
x = 2, y = 1, z = 1
x = 2, y = 1, z = 2
x = 1, y = 1, z = 2
To find the values of x, y, and z in the given chemical equation, we need to balance the equation by ensuring that the number of atoms of each element is the same on both the reactant and product sides. This adheres to the law of conservation of mass.
\(x\text{PbO(s)} + \text{C(s)} \rightarrow y\text{Pb(s)} + z\text{CO}_2\text{(g)}\)
On the reactant side, there is 1 C atom (from C(s)). On the product side, there is 1 C atom in \(\text{CO}_2\). So, the number of C atoms is already balanced if we assume \(z=1\). Let's start by assuming \(z=1\).
If \(z=1\), then on the product side, there are \(1 \times 2 = 2\) O atoms (from \(\text{CO}_2\)).
On the reactant side, there is 1 O atom in PbO. To have 2 O atoms on the reactant side, we need to multiply PbO by 2. So, \(x=2\).
Now that \(x=2\), on the reactant side, there are 2 Pb atoms (from \(2\text{PbO}\)).
On the product side, there is 1 Pb atom in Pb(s). To balance the Pb atoms, we need to multiply Pb(s) by 2. So, \(y=2\).
Substitute the values \(x=2\), \(y=2\), and \(z=1\) into the equation:
\(2\text{PbO(s)} + \text{C(s)} \rightarrow 2\text{Pb(s)} + \text{CO}_2\text{(g)}\)
Let's count the atoms on both sides:
All atoms are balanced.
Correct Option: A) x = 2, y = 2, z = 1
To find the distance of the end point from the initial point, we need to track Rahul's movements in the North-South and East-West directions separately. We can visualize this as a series of displacements on a 2D plane.
Thus, the end point is 20 km from the initial point.
Correct Option: C) 20 km
The question asks to identify the type of chemical reaction that human respiration represents. Respiration is a biological process where glucose is broken down in the presence of oxygen to produce carbon dioxide, water, and energy. We need to analyze the energy change associated with this reaction to classify it correctly.
D) exothermic reaction — Respiration involves the breakdown of glucose to release energy, which is used by the body for various functions. This release of energy, often as heat, classifies it as an exothermic reaction.
The question asks about a specific cricketing achievement by Jhulan Goswami on a particular date. To answer this, one needs to recall the details of this significant event in women's cricket history.
A) England is the correct answer. Jhulan Goswami achieved her record-breaking 250th ODI wicket against England on March 16, 2022, during the ICC Women's World Cup.
The question asks about a specific diplomatic gesture made by the Government of India as part of the Azadi Ka Amrit Mahotsav celebrations. This requires knowledge of recent international relations and cultural diplomacy initiatives.
A) Lycee Moderne Ampefiloha, Madagascar is the correct answer. The Government of India, as part of the Azadi Ka Amrit Mahotsav celebrations, donated 50 computers to this school in Madagascar, highlighting India's commitment to strengthening its partnership with African nations and supporting education.
To find the smaller of two consecutive even numbers whose sum is given, we can represent the numbers algebraically. Let the first even number be \(x\). Since the numbers are consecutive even numbers, the next even number will be \(x+2\). We then set up an equation where their sum equals the given value and solve for \(x\).
Let the smaller even number be \(x\).
Since the numbers are consecutive even numbers, the next even number will be \(x+2\).
The sum of these two consecutive even numbers is 842. So, we can write the equation:
\[ x + (x+2) = 842 \]Combine like terms:
\[ 2x + 2 = 842 \]Subtract 2 from both sides of the equation:
\[ 2x = 842 - 2 \]\[ 2x = 840 \]Divide by 2 to find the value of \(x\):
\[ x = \frac{840}{2} \]\[ x = 420 \]Since \(x\) represents the smaller even number, the smaller number is 420.
The smaller number is 420.
The larger number is \(x+2 = 420+2 = 422\).
Their sum is \(420 + 422 = 842\), which matches the given information.
Correct Option: B) 420 is the smaller of the two consecutive even numbers.
The question asks about the pH level at which tooth decay begins. This relates to the acidity of the mouth and its effect on tooth enamel. Understanding the pH scale and the composition of tooth enamel is key to answering this question.
A) pH below 5.5. This is the critical pH level at which the demineralization of tooth enamel begins, initiating the process of tooth decay.
This problem involves calculating the combined rate of filling and emptying to determine the net time taken to fill a cistern. We will find the individual rates of the tap and the hole, then combine them to find the effective filling rate, and finally calculate the total time.
C) 7.5 hours is the time taken to completely fill the empty cistern when both the tap and the hole are open.
The question asks for the incorporation year of the Steel Authority of India Ltd (SAIL). This requires knowledge of the historical establishment dates of major public sector undertakings in India.
Correct Option: A) 1973 is the correct year of incorporation for the Steel Authority of India Ltd (SAIL).
The question asks to identify which statement is NOT a change observed in children entering their teenage years (puberty). This requires knowledge of the common physical changes associated with puberty in both boys and girls.
A) Hair growth is seen in all parts of the body. This statement is incorrect because while hair growth increases in specific areas during puberty, it does not occur in literally all parts of the body for all individuals. For example, hair does not typically grow on the palms of the hands or soles of the feet.