Answer:
a) T
b) T
c) F
d) F
e) T
f) T
g) T
h) F
I) F
j) F
k) F
l) F
Explanation:
The w/v concentration is obtained from, mass/volume. Hence;
%w/v= 50/1000= 5%
In the %w/w we have;
25g/100 g = 25% w/w
In combustion reaction, energy is given out hence it is exothermic.
Neutralization reaction yields a salt and water
% by mass of carbon is obtained from;
8× 12/114 × 100 = 84.1%
All the ionic substances mentioned have very low solubility in water.
One mole of a substance contains the Avogadro's number of each atom in the compound.
There are two iron atoms so one mole contains 2× 55.85 g of iron.
Some sulphates such as BaSO4 are insoluble in water.
Halides are soluble in water hence NaI is soluble in water.
The equation does not balance with the given coefficients because the number of atoms of each element on both sides differ.
The equation represents a decomposition of calcium carbonate as written.
Radioactive material obeys 1st order decay kinetics,
For 1st order reaction, we have
k =
where, k = rate constant of reaction
Given: Initial conc. 100, Final conc. = 6.25, t = 18.9 hours
∴ k =
= 0.1467 hours^(-1)
Now, for 1st order reactions: half life =
= 4.723 hours.
Answer:
D) winds that blow in the same direction at a consistent speed
Explanation:
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Alchemists advanced the tools and procedures for working with chemicals. Alchemists also developed methods for sorting out mixtures and cleansing chemicals. They designed equipment that is still in use today including beakers, flasks, tongs, funnels, and the mortar and pestle. Also, Alchemists backed to an unbelievable variety of what would later be acquainted as chemical industries: basic metallurgy, metalworking, the invention of inks, dyes, paints, and cosmetics, leather-tanning, and the preparation of extracts and liquors.