Answer the following questions: - Noon Academy

Answer the following questions:

Chemistry | Class 10 | ICSE | Selina

Answer the following questions:

a)Name the three classes in which elements are classified.

(b) Which was the first metal used by man?

Answer:

(a) Metals, non-metals, and metalloids are the three types of elements classified. Copper was the first metal that man used. Back then, copper was used to making weapons, utensils, and a variety of other items.

(b) Aluminum is the most plentiful metal in the earth’s crust, while oxygen is the most abundant non-metal in the crust.

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(B) molecular weight
(C) atomic weight
(D) equivalent weight

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(D) $\mathrm{H}_{2} \mathrm{SO}_{5}$

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If $A(-2,0), B(0,4)$ and $C(0, k)$ be three points such that area of a $A B C$ is 4 sq units, find the value of $k$ .

Find the value of $k$ for which the area of a ABC having vertices $A(2,-6), B(5,4)$ and $C(k, 4)$ is 35 sq units.

Find the value of $k$ for which the points $A(1,-1), B(2, k)$ and $C(4,5)$ are collinear.

Find the value of $k$ for which the points $P(5,5), Q(k, 1)$ and $R(11,7)$ are collinear.

Find the value of $k$ for which the points $A(3,-2), B(k, 2)$ and $C(8,8)$ are collinear.

Use determinants to show that the following points are collinear. $P(-2,5), Q(-6,-7)$ and $R(-5,-4)$

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