A complex ore has the formula SiTiOx路2H2O. 903.67 g of this ore are roasted to expel the water and the resulting mass is 148.14 g. What is the value of x?

Use the following atomic/molecular weights: 28.09(Si), 47.88(Ti), 18.02(H2O).

Error tolerance: 卤0.01

A mole of a compound is composed of 6.02 x 1023 atoms of sodium, 35.45 g of chlorine, and 64.0 g of oxygen. The formula of the compound is
NaClO
NaClO2
Na(ClO2)2
NaClO3
NaClO4

Which of the following contains the greatest mass of oxygen?
1.0 mol O2
1.0 mol ozone (O3)
1.0 mole potassium chlorate
0.50 mol potassium dichromate
0.50 mol Na2S2O8

What is the ratio of oxygen atoms to hydrogen atoms in the mineral aluminate?
Formula: Al2(SO4)(OH)4路7H2O

Answer formats: XX:XX XX:X X:XX X:X

Example of answer format: 10:9

The atomic mass of Ga is about 69.72. There are only two naturally occurring isotopes, 69 & 71. The natural abundance of 69Ga must be approximately
30%
40%
50%
60%
70%

A certain compound has a MW of about 56 g/mol. All of the following are possible empirical formulas for this compound EXCEPT
CH2
CO
C3H4O
CH2O
CH2N

Place a check mark by all statements which are true concerning a chemical reaction.

The total mass of products equals the total mass of reactants.
The total moles of reactants must equal the total moles of products.
If a gas is evolved, the mass of products must be less than that of reactants.
The total number of atoms in the products must equal the total number of atoms in the reactants.
If the reactants are liquids and the products are gases, the density of the system decreases if the container is open to the atmosphere.
At least one of the products or reactants must be a solid.
Ratios of atoms in the products and reactants must be simple whole numbers.
Mass is conserved only in biochemical reactions.

What is the root-mean-square speed of a neon atom at 27掳C?
3.34 m/s
19.3 m/s
183 m/s
610 m/s

What is the pressure in a gas container that is connected to an open-end U-tube manometer if the pressure of the atmosphere is 772 torr and the level of mercury in the arm connect to the container is 8.60 cm higher than the level of mercury open to the atmosphere?
8.98 mm Hg
686 mm Hg
763 mm Hg
858 mm Hg

Rank the following in terms of increasing pressure, smallest (1) to largest (4).

– 355 torr
– 0.45 atm
– 0.524 atm
– 0.513 bar