it is covalent because it does not dissolve in water
Answer:
The empirical formula of a compound is Na2Cr2O7
Explanation:
Empirical formula is defined as the lowest ratio of elements present in any substance. In order to determine the empirical formula for a substance containing these elements we have to follow some steps.
1.In the first step, we have to divide the given mass of an element with its molecular mass to convert the mass to moles.

Similarly, the moles of Cr and O in that compound were calculated and found as 0.396 and 1.3875, respectively.
2. Then the next step is to determine the lowest moles and divide all the moles with that lowest mole. As here the lowest mole is 0.396. So on dividing the moles of Na, Cr and O with 0.396, we will obtain the ratio as 1:1:3.5.
3. As the ratio consists of a fractional number, we have to multiply it with the smallest possible integer to convert it to whole number. In this case, if we multiply it with 2 , we will get the ratio as 2:2:7.
Thus, the empirical formula for the compound can be written as Na2Cr2O7.
Answer:
28 g solute per 100 g of solution
Explanation:
28% mass means that in all your solution you have 28% of your solute, you could use grames/grames, ml/ml or whatever you want to. So if you are working with a 100 grams solution, 28 grams of that solution must be solute if you want a 28% mass. So, the correct answer is 28 g solute per 100 g of solution.
Answer:
A. Water
Explanation:
The formula for photosynthesis is carbon dioxide plus water which (with sunlight and chlorophyll) gets converted into glucose + oxygen, energy for the plant.
Without water, photosynthesis is unable to properly take place and plants are unable to produce the energy needed for them to continue maintaining life.